JP5573996B2 - Image encoding apparatus and method, recording medium, and program - Google Patents

Description

  The present invention relates to an image encoding apparatus and method, a recording medium, and a program, and more particularly to an image encoding apparatus and method, a recording medium, and a program that can suppress a reduction in encoding efficiency.

  In recent years, image information is handled as digital data, and MPEG (compressed by orthogonal transform such as discrete cosine transform and motion compensation is used for the purpose of efficient transmission and storage of information. A device conforming to a system such as Moving Picture Experts Group) is becoming popular in both information distribution at broadcasting stations and information reception in general households.

  In particular, MPEG2 (ISO (International Organization for Standardization) / IEC (International Electrotechnical Commission) 13818-2) is defined as a general-purpose image coding system, and includes both interlaced scanning images and progressive scanning images, as well as standard resolution images and This standard covers high-definition images and is currently widely used in a wide range of professional and consumer applications. By using the MPEG2 compression method, for example, a standard resolution interlaced scanning image having 720 × 480 pixels is 4 to 8 Mbps, and a high resolution interlaced scanning image having 1920 × 1088 pixels is 18 to 22 Mbps. (Bit rate) can be assigned to achieve a high compression rate and good image quality.

  MPEG2 was mainly intended for high-quality encoding suitable for broadcasting, but did not support encoding methods with a lower code amount (bit rate) than MPEG1, that is, a higher compression rate. With the widespread use of portable terminals, the need for such an encoding system is expected to increase in the future, and the MPEG4 encoding system has been standardized accordingly. Regarding the image coding system, the standard was approved as an international standard as ISO / IEC 14496-2 in December 1998.

  Furthermore, in recent years, the standardization of a standard called H.26L (ITU-T (ITU Telecommunication Standardization Sector) Q6 / 16 VCEG (Video Coding Experts Group)) has been advanced for the purpose of image coding for an initial video conference. H.26L is known to achieve higher encoding efficiency than a conventional encoding method such as MPEG2 or MPEG4, although a large amount of calculation is required for encoding and decoding. Also, as part of MPEG4 activities, standardization to achieve higher coding efficiency based on this H.26L and incorporating functions not supported by H.26L has been carried out as Joint Model of Enhanced-Compression Video Coding. It has been broken. As a standardization schedule, in March 2003, it became an international standard under the names of H.264 and MPEG4 Part 10 (AVC (Advanced Video Coding)).

  In addition, there is an adaptive loop filter (ALF (Adaptive Loop Filter)) as a next-generation video coding technique that has been recently examined (see, for example, Non-Patent Document 1). With this adaptive filter, optimal filter processing is performed for each frame, and block distortion that cannot be removed by the deblocking filter and distortion due to quantization can be reduced.

  However, since the image generally has various features locally, the optimum filter coefficient is different locally. In the method described in Non-Patent Document 1, since the same filter coefficient is applied to all the pixels in one frame, the image quality is improved in the entire frame, but there is a possibility that it is locally deteriorated.

  Therefore, a method of locally controlling the filter processing has been considered (see, for example, Non-Patent Document 2 and Non-Patent Document 3).

Yi-Jen Chiu and L. Xu, “Adaptive (Wiener) Filter for Video Compression,” ITU-T SG16 Contribution, C437, Geneva, April 2008. Takeshi. Chujoh, et al., “Block-based Adaptive Loop Filter” ITU-T SG16 Q6 VCEG Contribution, AI18, Germany, July, 2008 T. Chujoh, N. Wada and G. Yasuda, “Quadtree-based Adaptive Loop Filter,” ITU-T SG16 Q6 VCEG Contribution, VCEG-AK22 (r1), Japan, April, 2009

  However, no multi-slice is disclosed. Therefore, in the case of multi-slice, an ALF block for the entire frame is set for each slice, and unnecessary ALF blocks outside the slice area are set, which may unnecessarily reduce coding efficiency. It was.

  The present invention has been proposed in view of such a situation, and an object thereof is to suppress a reduction in coding efficiency.

One aspect of the present invention relates to slice control data for controlling adaptive filter processing on a slice to be processed of image data, and a quad included in the processing target slice when the adaptive filter processing is performed on the processing target slice. A generation unit that generates block control data for controlling whether to perform the adaptive filter processing for each pixel block of a tree structure, and the slice control data generated by the generation unit , or the slice control data and the block control It is an image coding apparatus provided with the encoding part which produces | generates an encoding stream using data, and the transmission part which transmits the said encoding stream produced | generated by the said encoding part.
It is determined whether the block is included in the processing target slice based on the position of the block obtained according to the block size of the block on which the adaptive filter processing is performed, and the block is included in the processing target slice. A determination unit that determines to perform the adaptive filter processing on the slice to be processed, wherein the generation unit is configured to determine the slice control data or the slice control data and the slice control data according to a determination result of the determination unit. The block control data can be generated.
The encoding unit may include the slice control data generated by the generation unit, or the slice control data and the block control data in the encoded stream as a predetermined syntax.
The encoding unit may include the slice control data in a slice header of the encoded stream.
The image processing apparatus may further include an adaptive filter unit that performs the adaptive filter process on the image data according to the slice control data and the block control data generated by the generation unit.
The image processing apparatus may further include a display control unit that displays the image subjected to the adaptive filter processing by the adaptive filter unit on a display.
A modulation unit that performs spread spectrum processing on the encoded stream generated by the encoding unit may be further provided, and the transmission unit may transmit the encoded stream that has been subjected to spread spectrum processing by the modulation unit.
When the end call and the power key are turned on by the user's operation, the power supply unit may be further started to be activated by supplying power from the battery pack to each processing unit.
The image processing apparatus further includes a signal processing unit that converts an image signal obtained by imaging the subject into Y, Cr, and Cb image data, and the generation unit generates the Y, Cr, and Cb images generated by the signal processing unit. For data, the slice control data and the block control data can be generated.
The image processing apparatus may further include a storage unit that stores Y, Cr, and Cb image data generated by the signal processing unit or an encoded stream generated by the encoding unit.
The transmission unit can transmit the encoded data read from the storage unit.

According to another aspect of the present invention, when generating slice control data for controlling adaptive filter processing on a slice to be processed of image data and performing the adaptive filter processing on the processing target slice, the processing target is further of generating the block control data for controlling whether to perform the adaptive filtering process for each pixel block of the quad-tree structure included in the slice, it generated the slice control data, or, the slice control data and the block control data used to generate a coded stream, a generated image coding method for transmitting the encoded stream.
It is determined whether the block is included in the processing target slice based on the position of the block obtained according to the block size of the block on which the adaptive filter processing is performed, and the block is included in the processing target slice. In this case, it is determined that the adaptive filter processing is performed on the processing target slice, and the slice control data, or the slice control data and the block control data can be generated according to the determination result.
The generated slice control data, or the slice control data and the block control data may be included in the encoded stream as a predetermined syntax.
The slice control data may be included in a slice header of the encoded stream.
The adaptive filter processing can be performed on the image data according to the generated slice control data and the block control data.
The adaptively filtered image can be displayed on a display.
The generated encoded stream can be subjected to a spread spectrum process, and the encoded stream subjected to the spread spectrum process can be transmitted.
When the end call and the power key are turned on by the user's operation, it is possible to start operation by supplying power from the battery pack to each processing unit.
An image signal obtained by imaging a subject is converted into Y, Cr, and Cb image data, and the slice control data and the block control data are generated for the generated Y, Cr, and Cb image data. Can do.
The generated Y, Cr, Cb image data or the generated encoded stream can be stored in the storage unit.
The encoded data read from the storage unit can be transmitted.

According to one aspect of the present invention, when the computer further performs slice control data for controlling adaptive filter processing on a slice to be processed of image data, and the adaptive filter processing on the slice to be processed , the processing target A generating unit that generates block control data for controlling whether to perform the adaptive filter processing for each pixel block having a quad tree structure included in a slice; and the slice control data generated by the generating unit , or the slice control Using the data and the block control data , a computer that records an encoding unit that generates an encoded stream and a program that functions as a transmission unit that transmits the encoded stream generated by the encoding unit is readable It is a recording medium.

According to another aspect of the present invention, when the computer performs slice control data for controlling adaptive filter processing on a slice to be processed of image data and the adaptive filter processing on the slice to be processed , the processing target A generating unit that generates block control data for controlling whether to perform the adaptive filter processing for each pixel block having a quad tree structure included in a slice; and the slice control data generated by the generating unit , or the slice control A program that functions as an encoding unit that generates an encoded stream by using data and the block control data, and a transmission unit that transmits the encoded stream generated by the encoding unit.

In one aspect of the present invention, when slice control data for controlling adaptive filter processing to a slice to be processed of image data is generated, and adaptive filter processing is performed on a slice to be processed, the slice control data is further included in the slice to be processed. block control data for controlling whether to perform adaptive filtering process for each pixel block of the quad-tree structure is generated, the generated slice control data, or, using a slice control data and block control data, the coded stream is generated Then, the generated encoded stream is transmitted.

  According to the present invention, an image can be encoded. In particular, a reduction in encoding efficiency can be suppressed.

It is a block diagram which shows the main structural examples of the image coding apparatus to which this invention is applied. It is a figure explaining variable block size motion prediction and compensation processing. It is a block diagram which shows the main structural examples of a control information generation part. It is a figure explaining an ALF block and a filter block flag. It is a figure explaining the example of multi-slice. It is a figure explaining the process of slice 0. FIG. It is a figure explaining the process of slice 1. FIG. It is a figure explaining the process of the slice 1 to which this invention is applied. It is a figure explaining the offset of an ALF block. It is a block diagram which shows the main structural examples of an adaptive filter process part. It is a flowchart explaining the example of the flow of an encoding process. It is a figure explaining the example of the syntax of a slice header. It is a figure explaining the example of the syntax of a slice header. It is a flowchart explaining the example of the flow of a control information generation process. It is a flowchart explaining the example of the flow of a block information generation process. It is a flowchart explaining the example of the flow of an adaptive filter process. It is a block diagram which shows the main structural examples of the image decoding apparatus to which this invention is applied. It is a flowchart explaining the example of the flow of a decoding process. It is a flowchart explaining the other example of the flow of a block information generation process. It is a figure explaining the example of the offset of the ALF block with respect to the change of a texture. It is a figure explaining the example of the mode of an offset. It is a figure explaining the example of the mode of a change of ALF block size. It is a block diagram which shows the other structural example of a control information generation part. It is a flowchart explaining the other example of the flow of a control information generation process. It is a figure explaining the other example of an ALF block and a filter block flag. It is a figure explaining the other example of an ALF block and a filter block flag. It is a figure explaining the mode of processing in the case of multi-slice. It is a figure explaining the example of the syntax of a slice header. It is a block diagram which shows the main structural examples of the personal computer to which this invention is applied. It is a block diagram which shows the main structural examples of the television receiver to which this invention is applied. It is a block diagram which shows the main structural examples of the mobile telephone to which this invention is applied. It is a block diagram which shows the main structural examples of the hard disk recorder to which this invention is applied. It is a block diagram which shows the main structural examples of the camera to which this invention is applied. It is a figure which shows the example of a macroblock.

Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described. The description will be given in the following order.
1. First Embodiment (Image Encoding Device)
2. Second embodiment (image decoding apparatus)
3. Third embodiment (variation of filter block flag generation processing)
4). Fourth embodiment (control information generator)
5. Fifth embodiment (QALF)
6). Sixth embodiment (personal computer)
7). Seventh embodiment (television receiver)
8). Eighth embodiment (mobile phone)
9. Ninth embodiment (hard disk recorder)
10. Tenth embodiment (camera)

<1. First Embodiment>
[Device Configuration]
FIG. 1 shows a configuration of an embodiment of an image encoding apparatus as an image processing apparatus to which the present invention is applied.

  An image encoding device 100 shown in FIG. It is an encoding device that compresses and encodes an image using an H.264 and MPEG4 Part 10 (Advanced Video Coding) (hereinafter referred to as H.264 / AVC) method, and further employs an adaptive loop filter.

  In the example of FIG. 1, the image encoding device 100 includes an A / D (Analog / Digital) conversion unit 101, a screen rearrangement buffer 102, a calculation unit 103, an orthogonal conversion unit 104, a quantization unit 105, and a lossless encoding unit 106. And a storage buffer 107. In addition, the image coding apparatus 100 includes an inverse quantization unit 108, an inverse orthogonal transform unit 109, a calculation unit 110, and a deblock filter 111. Furthermore, the image coding apparatus 100 includes a control information generation unit 112, an adaptive filter processing unit 113, and a frame memory 114. In addition, the image encoding device 100 includes an intra prediction unit 115, a motion compensation unit 116, a motion prediction unit 117, and a predicted image selection unit 118. Furthermore, the image encoding device 100 includes a rate control unit 119.

  The A / D conversion unit 101 performs A / D conversion on the input image, outputs it to the screen rearrangement buffer 102, and stores it. The screen rearrangement buffer 102 rearranges the stored frame images in the display order in the order of frames for encoding in accordance with the GOP (Group of Picture) structure.

  The calculation unit 103 subtracts the prediction image from the intra prediction unit 115 selected by the prediction image selection unit 118 or the prediction image from the motion compensation unit 116 from the image read from the screen rearrangement buffer 102, and the difference between them. Information is output to the orthogonal transform unit 104. The orthogonal transform unit 104 performs orthogonal transform such as discrete cosine transform and Karhunen-Loeve transform on the difference information from the operation unit 103, and outputs the transform coefficient. The quantization unit 105 quantizes the transform coefficient output from the orthogonal transform unit 104.

  The quantized transform coefficient that is output from the quantization unit 105 is input to the lossless encoding unit 106. The lossless encoding unit 106 compresses the quantized transform coefficient by performing lossless encoding such as variable-length encoding or arithmetic encoding.

  The lossless encoding unit 106 acquires information indicating intra prediction from the intra prediction unit 115 and acquires information indicating inter prediction mode from the motion prediction unit 117. Note that information indicating intra prediction is hereinafter also referred to as intra prediction mode information. In addition, information indicating an information mode indicating inter prediction is hereinafter also referred to as inter prediction mode information.

  The lossless encoding unit 106 further acquires control information of adaptive filter processing performed in the adaptive filter processing unit 113 from the control information generation unit 112.

  The lossless encoding unit 106 encodes the quantized transform coefficient, encodes control information for adaptive filter processing, information indicating intra prediction, information indicating inter prediction mode, a quantization parameter, and the like. As part of the header information in (multiplex). The lossless encoding unit 106 supplies the encoded data to the accumulation buffer 107 for accumulation.

  For example, the lossless encoding unit 106 performs lossless encoding processing such as variable length encoding or arithmetic encoding. Examples of variable length coding include H.264. CAVLC (Context-Adaptive Variable Length Coding) defined in H.264 / AVC format. Examples of arithmetic coding include CABAC (Context-Adaptive Binary Arithmetic Coding).

  The accumulation buffer 107 temporarily retains the data supplied from the lossless encoding unit 106, and at a predetermined timing, the H.264 buffer. As a compressed image encoded by the H.264 / AVC format, for example, it is output to a recording device or a transmission path (not shown) in the subsequent stage.

  Further, the transform coefficient quantized by the quantization unit 105 is also input to the inverse quantization unit 108. The inverse quantization unit 108 inversely quantizes the quantized transform coefficient by a method corresponding to the quantization by the quantization unit 105, and supplies the obtained transform coefficient to the inverse orthogonal transform unit 109.

  The inverse orthogonal transform unit 109 performs inverse orthogonal transform on the supplied transform coefficient by a method corresponding to the orthogonal transform process by the orthogonal transform unit 104. The output subjected to inverse orthogonal transform is supplied to the calculation unit 110. The calculation unit 110 adds the predicted image supplied from the predicted image selection unit 118 to the inverse orthogonal transform result supplied from the inverse orthogonal transform unit 109, that is, the restored difference information, and locally decoded image (Decoded image) is obtained. The addition result is supplied to the deblocking filter 111.

  The deblocking filter 111 removes block distortion of the decoded image. The deblocking filter 111 supplies the distortion removal result to the control information generation unit 112 and the adaptive filter processing unit 113.

  The control information generation unit 112 acquires the decoded image supplied from the deblocking filter 111 and the current input image read from the screen rearrangement buffer 102, and uses the adaptive filter performed by the adaptive filter processing unit 113 from them. Control information is generated. Although details will be described later, the control information includes a filter coefficient, an ALF block size, a filter block flag, an offset value of the ALF block, and the like.

  The control information generation unit 112 supplies the generated control information to the adaptive filter processing unit 113. The control information generation unit 112 also supplies the generated control information to the lossless encoding unit 106. As described above, the control information is subjected to lossless compression processing by the lossless encoding unit 106 and is included (multiplexed) in the image compression information. That is, the control information is sent to the image decoding apparatus together with the image compression information.

  The adaptive filter processing unit 113 is supplied from the deblocking filter 111 using information such as a filter coefficient, an ALF block size, a filter block flag, and an offset value included in the control information supplied from the control information generating unit 112. Filter processing is performed on the decoded image. As this filter, for example, a Wiener Filter is used. Of course, filters other than the Wiener filter may be used. The adaptive filter processing unit 113 supplies the filter processing result to the frame memory 114 and accumulates it as a reference image.

  The frame memory 114 outputs the stored reference image to the motion compensation unit 116 and the motion prediction unit 117 at a predetermined timing.

  In this image encoding device 100, for example, an I picture, a B picture, and a P picture from the screen rearrangement buffer 102 are supplied to the intra prediction unit 115 as images to be intra predicted (also referred to as intra processing). In addition, the B picture and the P picture read from the screen rearrangement buffer 102 are supplied to the motion prediction unit 117 as images to be inter predicted (also referred to as inter processing).

  The intra prediction unit 115 performs intra prediction processing for all candidate intra prediction modes based on the intra-predicted image read from the screen rearrangement buffer 102 and the reference image supplied from the frame memory 114, and performs prediction. Generate an image.

  In the intra prediction unit 115, information on the intra prediction mode applied to the block / macroblock is transmitted to the lossless encoding unit 106 and encoded as part of header information in the image compression information. In the H.264 image information encoding method, an intra 4 × 4 prediction mode, an intra 8 × 8 prediction mode, and an intra 16 × 16 prediction mode are defined for the luminance signal, and regarding the color difference signal, For each macroblock, it is possible to define a prediction mode independent of the luminance signal. For the intra 4 × 4 prediction mode, one intra prediction mode is defined for each 4 × 4 luminance block. For the intra 8 × 8 prediction mode, one intra prediction mode is defined for each 8 × 8 luminance block. For the intra 16 × 16 prediction mode and the color difference signal, one prediction mode is defined for each macroblock.

  The intra prediction unit 115 calculates a cost function value for the intra prediction mode in which the predicted image is generated, and selects an intra prediction mode in which the calculated cost function value gives the minimum value as the optimal intra prediction mode. The intra prediction unit 115 supplies the predicted image generated in the optimal intra prediction mode to the predicted image selection unit 118.

  The motion prediction unit 117 uses the image information (input image) supplied from the screen rearrangement buffer 102 and the image information (decoded image) serving as a reference frame supplied from the frame memory 114 for the image to be inter-coded. Obtain the motion vector. The motion prediction unit 117 supplies motion vector information indicating the calculated motion vector to the lossless encoding unit 106. This motion vector information is subjected to lossless compression processing by the lossless encoding unit 106 and is included in the image compression information. That is, the motion vector information is sent to the image decoding device together with the image compression information.

  The motion prediction unit 117 also supplies the motion vector information to the motion compensation unit 116.

  The motion compensation unit 116 performs motion compensation processing according to the motion vector information supplied from the motion prediction unit 117, and generates inter prediction image information. The motion compensation unit 116 supplies the generated predicted image information to the predicted image selection unit 118.

  The predicted image selection unit 118 supplies the output of the intra prediction unit 115 to the calculation unit 103 in the case of an image to be subjected to intra coding, and outputs the output of the motion compensation unit 116 to the calculation unit 103 in the case of an image to be subjected to inter coding. Supply.

  Based on the compressed image stored in the storage buffer 107, the rate control unit 119 controls the quantization operation rate of the quantization unit 105 so that overflow or underflow does not occur.

  In MPEG (Moving Picture Experts Group) 2, the unit of motion prediction / compensation processing is a motion compensation block, and each motion compensation block can have independent motion vector information. The size of the motion compensation block is 16 × 16 pixels in the frame motion compensation mode, and 16 × 8 pixels in each of the first field and the second field in the field motion compensation mode.

  On the other hand, in AVC (Advanced Video Coding), as shown in the upper side of FIG. 2, one macro block composed of 16 × 16 pixels is converted into 16 × 16, 16 × 8, 8 × 16, or 8 × 8. It is possible to divide each of the partitions into independent motion vector information. Further, as shown in the lower side of FIG. 2, the 8 × 8 partition is divided into 8 × 8, 8 × 4, 4 × 8, and 4 × 4 subpartitions, and independent motion vector information is obtained. It is possible to have. Motion prediction / compensation processing is performed in units of this motion compensation block.

  FIG. 3 is a block diagram illustrating a main configuration example of the control information generation unit 112.

  As described above, the control information generation unit 112 generates control information used in the adaptive filter (ALF (Adaptive Loop Filter)) that is a loop filter performed in the adaptive filter processing unit 113. The control information generation unit 112 generates, for example, a filter coefficient, an ALF block size, a filter block flag, and an ALF block offset value as the control information.

  The control information generation unit 112 includes a filter coefficient calculation unit 131 and a block information generation unit 132.

  The filter coefficient calculation unit 131 acquires the decoded image supplied from the deblocking filter 111 and the current input image read from the screen rearrangement buffer 102, and from these, the adaptive filter processing unit 113 performs each frame. Calculate the ALF filter coefficients to be performed.

  The block information generation unit 132 determines the ALF block size based on the decoded image supplied from the deblocking filter 111 and the filter coefficient calculated by the filter coefficient calculation unit 131, arranges the ALF block, and sets the ALF block. An appropriate offset value is obtained, the ALF block is moved, and a filter block flag is generated for each ALF block in the processing target slice.

  Here, the ALF block and the filter block flag will be described. FIG. 4 is a diagram for explaining the ALF block and the filter block flag.

  As described above, in the adaptive filter, a filter coefficient is set for each frame. That is, optimal filter processing is performed on a frame basis. However, in general, the frame image is not uniform as a whole and has various features locally. Therefore, the optimum filter coefficient is locally different. Therefore, as described above, in the filter processing using the filter coefficient determined for each frame, the image quality is improved in the entire frame, but there is a possibility that it may be deteriorated locally.

  In view of this, a BALF (Block based Adaptive Loop Filter) has been considered in which filter processing is not performed in a region where image quality locally deteriorates.

  A frame 151 in FIG. 4A shows a decoded image after the deblocking filter process. As shown in FIG. 4B, the block information generation unit 132 adds a plurality of ALF blocks 152, each of which is a control unit of adaptive filter processing performed locally, to the entire area of the frame 151. Arrange them without gaps so that they are spread. The block information generation unit 132 uses a predetermined position of the frame 151 as a reference point, and determines an arrangement position of each ALF block 152 using the reference point as a reference.

  Here, “arrangement” is to determine (specify or set) the control target area (position) of each control block. That is, each control block is set to be assigned to different partial areas of the image (frame 151). Therefore, the data is not actually superimposed (synthesized).

  The area where the ALF block 152 is arranged may not be the same as the area of the frame 151 but includes at least the entire area of the frame. As a result, the area of the frame 151 is divided by the area (a plurality of areas) of each ALF block 152.

  The block information generation unit 132 determines the horizontal size (double arrow 153) and the vertical size (double arrow 154) of the ALF block 152. For the ALF block size, for example, one of 8 × 8, 16 × 16, 24 × 24, 32 × 32, 48 × 48, 64 × 64, 96 × 96, or 128 × 128 is designated for each slice. can do. Information specifying the size of the ALF block is referred to as a block size index.

  If the block size is determined, the frame size is fixed, so the number of ALF blocks per frame is also determined.

  As illustrated in FIG. 4C, the block information generation unit 132 sets a filter block flag 155 that controls whether to perform filter processing for each ALF block 152. For example, a filter block flag 155 having a value “1” is generated for a region where the image quality is improved by the adaptive filter, and a filter block flag 155 having a value “0” is generated for a region where the image quality is deteriorated by the adaptive filter. Generated. In the filter block flag 155, the value “1” is a value indicating that the filtering process is performed, and the value “0” is a value indicating that the filtering process is not performed.

  The adaptive filter processing unit 113 controls adaptive filter processing based on the value of the filter block flag 155. For example, the adaptive filter processing unit 113 performs the filtering process only on the area of the ALF block 152 in which the value of the filter block flag 155 is “1”, and the area of the ALF block 152 in which the value of the filter block flag 155 is “0”. Do not filter.

  The ALF block size and the filter block flag described above are included in the slice header of the image compression information, and are sent from the image coding apparatus 100 to the image decoding apparatus. One or more filter block flags corresponding to the number of ALF blocks 152 are included in the slice header in the raster scan order, for example.

  Therefore, as the ALF block size is smaller, finer filter control is possible, and a more appropriate ALF filter is possible. However, if the size of the ALF block is reduced, the bit amount of the filter block flag increases. That is, as the size of the ALF block is smaller, the encoding efficiency of the image compression information is reduced. Thus, the performance of the adaptive filter and the coding efficiency of the image compression information are in a trade-off relationship.

  The number of ALF blocks is calculated as in the following equation (1).

In Formula (1), N _ALFBLOCK indicates the number of ALF blocks. N _MBw represents the number of macroblocks in the horizontal direction of the picture, and N _MBh represents the number of _macrobooks in the vertical direction of the picture. Further, N _SIZE indicates the size of one side of the ALF block. Floor [x] is a function that rounds off the decimal point of x to an integer.

  By the way, in H.264 / AVC, one frame can be divided into a plurality of slices, and image compression information can be output for each slice. FIG. 5 is a diagram illustrating an example of multi-slice. In the example of FIG. 5, the frame 151 is divided into three slices, slice 0, slice 1, and slice 2.

  By outputting the image compression information in units of slices smaller than such a frame, the image encoding device 100 can generate and output the image compression information at shorter intervals. That is, an image decoding apparatus that decodes the compressed image information can start decoding the compressed image information earlier. That is, the delay time from when an image is input to when the encoding process and the decoding process are performed and the image is output can be shortened.

  Non-patent document 2 describing BALF does not disclose this multi-slice. That is, only the setting of the ALF block for the entire frame is described. In order to generate the filter block flag, a deblocked decoded image is required. Therefore, if the filter block flag for the entire frame is generated at a time, it is necessary to wait until an image is encoded for all slices in the frame (until a decoded image subjected to deblocking filtering is obtained). . In this case, the delay time increases for this reason, and the meaning of performing processing in units of slices is lost.

  Therefore, in the case of multi-slice, it is desirable to set an ALF block for each slice and generate a filter block flag in order to suppress an increase in delay time. However, as described above, the ALF block is set for the entire frame. That is, an ALF block for the entire frame is set for each slice, and there is a possibility that an unnecessary ALF block outside the slice area is set.

  For example, when the slice 0 is processed as shown in FIG. 6A in the example of FIG. 5, the ALF block 152 for the entire frame 151 is processed with respect to the area of the slice 0 shown by the frame 161 as shown in FIG. 6B. Is set.

  Similarly, for example, in the case of processing slice 1 as shown in FIG. 7A in the example of FIG. 5, as shown in FIG. 7B, for the region of slice 1 shown by the frame 162, the entire frame 151 is processed. An ALF block 152 is set.

  6B and 7B, the ALF block 152 indicated by hatching is a block outside the area of slice 0 or slice 1, and is an unnecessary block for processing of the area of slice 0 or slice 1.

  As described above, the filter block flag 155 is set in each ALF block. That is, in the case of multi-slice, an unnecessary filter block flag is generated, which may increase the data amount of the image compression information and reduce the encoding efficiency.

  Therefore, the block information generation unit 132 of the control information generation unit 112 in FIG. 3 generates an ALF block and a filter block flag including the region of the slice to be processed in order to suppress such a reduction in encoding efficiency.

  For example, when the slice 1 is processed as illustrated in FIG. 8A in the example of FIG. 5, the block information generation unit 132 performs the processing on the area of slice 1 indicated by the frame 162 as illustrated in FIG. 8B. Only the ALF block 152 including the area is set, and the filter block flag is generated only for the ALF block 152.

  In this way, only the filter block flag necessary for each slice is added to the image compression information. As described above, the filter block flag for the entire frame is generated for each slice. Thus, since the bit amount of the filter block flag is reduced, the reduction in coding efficiency is suppressed. In addition, since image compression information including control information is generated for each slice, the image decoding apparatus can start image decoding processing in units of slices, compared to a case where a filter block flag is generated for each frame. An increase in delay time can be suppressed.

  At this time, as shown in FIG. 8B, the ALF block 152 including the end portion of the slice 1 area indicated by the frame 162 (that is, the boundary of the slice) is part of the slice 1 area. Therefore, the filtering process is performed. In other words, it is necessary to perform the filtering process even though the slice 1 region exists only in a part of the region.

  As shown in FIG. 8B, when the position of the boundary of the slice and the position of the boundary of the ALF block 152 are shifted from each other, the number of ALF blocks including such a boundary of the slice increases, and as a result, the filter for the slice 1 The number of filter block flag bits (ALF block number) required for processing increases.

  For example, as shown in FIG. 9A, when filtering the slice 1 area of the frame 151, the positional relationship between the ALF block arranged for the entire frame 151 and the slice 1 area indicated by the frame 162. Is as shown in FIG. 9B.

  In this case, the number of filter block flags (ALF blocks including the slice 1 area) necessary for the filter processing on slice 1 is 39.

  In the state of FIG. 9B, for example, the position of the ALF block 152 is moved upward as indicated by the arrow 163, and the upper boundary of the slice 1 and the boundary of the ALF block 152 are made to coincide. At this time, the positional relationship between the ALF block 152 and the frame 162 is as shown in FIG. 9C.

  In this case, the number of filter block flags (ALF blocks including the area of slice 1) necessary for the filter processing on slice 1 is 28.

  In this way, by controlling to move the position of the ALF block, the block information generation unit 132 can reduce the number of bits of the necessary filter block flag. As described above, since the filter block flag is also added to the image compression information, it is possible to suppress an increase in encoding efficiency.

  In addition, in the case of an ALF block including a slice boundary as described above, data for the next slice must be generated, dummy data must be generated, filter processing becomes complicated, and delay time is increased. May increase. Since the block information generation unit 132 performs control so as to move the position of the ALF block as described above, the number of ALF blocks including the boundary of the slice is reduced, and as a result, the filtering process becomes easier and the delay time is reduced. The increase can be suppressed.

  Furthermore, the image quality of the slice boundary portion may deteriorate due to image processing such as synthesis with the next slice or generation of dummy data, and the effect of the filter processing may be reduced. Since the block information generation unit 132 performs control so that the position of the ALF block is moved as described above, the number of ALF blocks including the boundary of the slice is reduced, and as a result, the reduction of the filter processing effect is suppressed. Can do.

  Returning to FIG. 3, the block information generating unit 132 includes a processing target slice area specifying unit 141, an ALF block setting unit 142, an offset processing unit 143, a processing target ALF block area specifying unit 144, a determining unit 145, and a filter block flag generating unit. 146.

  The processing target slice area specifying unit 141 specifies the position in the entire frame of the area of the processing target slice supplied as a decoded image.

  The ALF block setting unit 142 determines the ALF block size and sets a plurality of ALF blocks 152 in the entire frame. The ALF block setting unit 142 determines a position of each ALF block 152 using a predetermined position of the frame as a reference point, and arranges the ALF block 152 so as to cover the frame area without any gap. This reference point can be set at an arbitrary position in the frame. For example, the pixel may be the upper left pixel of the frame, the upper right end, the lower right end, the lower left end, or the center of the frame.

  Since the size of the area of the entire frame is determined in advance, the ALF block setting unit 142 can specify the number of ALF blocks of the entire frame from the determined ALF block size.

  The offset processing unit 143 updates the position of the ALF block 152 arranged by the ALF block setting unit 142 as appropriate. The offset processing unit 143 moves all the ALF blocks 152 so that the boundaries of the ALF blocks 152 are aligned with the ends of the slices. First, the offset processing unit 143 improves the filter processing result from the initial arrangement position determined based on the reference point (for example, the position where the boundary of the ALF block 152 is aligned with the end of the processing target slice (destination)). ) To obtain an offset value indicating the movement distance and the movement direction. Since the processing target slice area specifying unit 141 specifies the position of the processing target slice, the offset processing unit 143 determines an offset value (destination) based on the position information.

  It should be noted that the “end” of the processing target slice serving as a reference for determining the destination may be any side of the outer shape of the processing target slice. For example, in the example of FIG. 9C, the boundary of the ALF block 152 is aligned with the upper end of the processing target slice (slice 1). The offset processing unit 143 may be able to select an optimum side for aligning the boundary of the ALF block 152 from each side of the outline of the processing target slice.

  When the offset value is obtained, the offset processing unit 143 moves all the ALF blocks 152 arranged in the frame by the offset value. Subsequent processing is performed based on the ALF block 152 in which the position is updated.

  The processing target ALF block area specifying unit 144 selects ALF blocks to be processed one by one from the ALF blocks 152 set by the ALF block setting unit 142 and appropriately moved by the offset processing unit 143, and the selected processing Specify the location of the target ALF block area.

  The determination unit 145 determines whether the region of the processing target ALF block includes the region of the processing target slice. The filter block flag generation unit 146 generates a filter block flag for the ALF block determined by the determination unit 145 as “including the area of the slice to be processed”. The filter block flag generation unit 146 performs adaptive filter processing on the region of the processing target ALF block using the filter coefficient calculated by the filter coefficient calculation unit 131, and the image quality of the filter processing result is improved from before the processing. The value of the filter block flag is determined depending on whether or not it exists.

  The filter block flag generation unit 146 outputs control information such as a filter block flag, an ALF block size, and an offset value.

  FIG. 10 is a block diagram illustrating a main configuration example of the adaptive filter processing unit 113 in FIG.

  The adaptive filter processing unit 113 performs filter processing on the decoded image supplied from the deblocking filter 111 using the control information supplied from the control information generating unit 112.

  As illustrated in FIG. 9, the adaptive filter processing unit 113 includes a control unit 171, an adaptive filter 172, and a selection unit 173.

  The control unit 171 controls the adaptive filter 172 and the selection unit 173. For example, the control unit 171 acquires control information from the control information generation unit 112. In addition, the control unit 171 supplies the filter coefficient included in the acquired control information to the adaptive filter 172 and sets it. Further, the control unit 171 specifies the position of the region of the ALF block to be processed based on the ALF block size and the offset value included in the control information. Further, the control unit 171 controls the adaptive filter 172 based on the value of the filter block flag included in the control information, performs filter processing on the area of each ALF block as necessary, and controls the operation of the selection unit 173. To do.

  The adaptive filter 172 filters the region specified as the processing target ALF block by the control unit 171 of the decoded image supplied from the deblocking filter 111 using the filter coefficient set by the control unit 171. The adaptive filter 172 supplies the filter processing result to the selection unit 173.

  The selection unit 173 is controlled by the control unit 171, and the decoded image (decoded image not subjected to adaptive filter processing) supplied from the deblocking filter 111 and the decoded image (decoded image subjected to adaptive filter processing) supplied from the adaptive filter 172. Image) is supplied to the frame memory 114 and stored as a reference image.

  That is, the adaptive filter processing unit 113 indicates that the decoded image supplied from the deblocking filter 111 is subjected to the filter processing by the filter block flag (region determined to improve the image quality by the filter processing). Only filter.

[Process flow]
Next, the flow of processing using each unit configured as described above will be described. First, an example of the flow of encoding processing performed by the image encoding device 100 will be described with reference to the flowchart of FIG.

  In step S101, the A / D conversion unit 101 performs A / D conversion on the input image. In step S102, the screen rearrangement buffer 102 stores the A / D converted image, and rearranges the picture from the display order to the encoding order.

  In step S103, the calculation unit 103 calculates the difference between the image rearranged by the process in step S102 and the predicted image. The predicted image is supplied from the motion compensation unit 116 in the case of inter prediction, and from the intra prediction unit 115 in the case of intra prediction, to the calculation unit 103 via the predicted image selection unit 118, respectively.

  The difference data has a smaller data amount than the original image data. Therefore, the data amount can be compressed as compared with the case where the image is encoded as it is.

  In step S104, the orthogonal transform unit 104 performs orthogonal transform on the difference information generated by the process in step S103. Specifically, orthogonal transformation such as discrete cosine transformation and Karhunen-Loeve transformation is performed, and transformation coefficients are output. In step S105, the quantization unit 105 quantizes the transform coefficient. At the time of this quantization, the rate is controlled as described in the process of step S119 described later.

  The difference information quantized as described above is locally decoded as follows. That is, in step S106, the inverse quantization unit 108 inversely quantizes the transform coefficient quantized by the quantization unit 105 with characteristics corresponding to the characteristics of the quantization unit 105. In step S <b> 107, the inverse orthogonal transform unit 109 performs inverse orthogonal transform on the transform coefficient inversely quantized by the inverse quantization unit 108 with characteristics corresponding to the characteristics of the orthogonal transform unit 104.

  In step S108, the calculation unit 110 adds the predicted image input via the predicted image selection unit 118 to the locally decoded difference information, and outputs the locally decoded image (for input to the calculation unit 103). Corresponding image). In step S <b> 109, the deblocking filter 111 filters the image output from the calculation unit 110. Thereby, block distortion is removed.

  When the above processing is performed for one slice, in step S110, the control information generation unit 112 generates control information used for adaptive filter processing. Details of the control information generation process will be described later.

  When the control information such as the filter coefficient, the ALF block size, the filter block flag, and the offset value is generated by the process in step S110, the adaptive filter processing unit 113 uses the control information in step S111 to perform step S109. The adaptive filter process is performed on the decoded image that has been deblocked by the above process. Details of the adaptive filter processing will be described later.

  In step S112, the frame memory 114 stores the image subjected to the adaptive filter processing in step S111.

  In step S113, the intra prediction unit 115 performs an intra prediction process in the intra prediction mode. In step S114, the motion prediction unit 117 and the motion compensation unit 116 perform inter motion prediction / compensation processing in the inter prediction mode.

  In step S115, the predicted image selection unit 118 selects either the predicted image generated by the intra prediction process or the predicted image generated by the inter motion prediction / compensation process, according to the prediction mode of the processing target frame. Select one. The predicted image selection unit 118 supplies the selected predicted image to the calculation unit 103 and the calculation unit 110. As described above, this predicted image is used for the calculations in step S103 and step S108.

  In step S116, the lossless encoding unit 106 encodes the quantized transform coefficient output from the quantization unit 105. That is, the difference image is subjected to lossless encoding such as variable length encoding and arithmetic encoding, and is compressed. At this time, the lossless encoding unit 106 also encodes the control information generated in step S110, the intra prediction mode information in the intra prediction process in step S113, the inter prediction mode in the inter motion prediction / compensation process in step S114, and the like. To do.

  In step S117, the lossless encoding unit 106 embeds (describes) encoded metadata such as control information in a slice header. For example, embedding (description) of control information in a slice header is performed based on the syntax as shown in FIGS. This metadata is read and used at the time of image decoding. Thus, by including (multiplexing) the metadata necessary for the decoding process in the slice header, the decoding process can be executed in a unit smaller than the frame unit, and an increase in delay time can be suppressed.

  In step S118, the accumulation buffer 107 accumulates the difference image as a compressed image. The compressed image stored in the storage buffer 107 is appropriately read and transmitted to the decoding side via the transmission path.

  In step S119, the rate control unit 119 controls the rate of the quantization operation of the quantization unit 105 based on the compressed image stored in the storage buffer 107 so that overflow or underflow does not occur.

  Next, an example of the flow of control information generation processing executed by the control information generation unit 112 in step S110 of FIG. 11 will be described with reference to the flowchart of FIG.

  When the control information generation process is started, the filter coefficient calculation unit 131 of the control information generation unit 112 receives the input image supplied from the screen rearrangement buffer 102 and the deblock supplied from the deblock filter 111 in step S131. A filter coefficient is calculated using the decoded image after filtering. For example, the filter coefficient calculation unit 131 determines the filter coefficient value so that the residual between the input image and the decoded image is minimized.

  When the filter coefficient is calculated, the block information generation unit 132 generates block information including an ALF block size, an offset value, and a filter block flag in step S132. Details of the block information generation processing will be described later. When the block information is generated, the process returns to step S110 in FIG. 11 and the processes after step S111 are executed.

  Note that the filter coefficient calculation performed in step S131 may be performed in units of frames. In this case, the process in step S131 is performed for a predetermined slice in the frame (for example, a slice whose identification number has a predetermined value (for example, “0”) or a slice that is processed first in the frame). It may be performed only in step 1, and the value may be used in other slices. An arbitrary image can be used for calculating the filter coefficient. For example, it may be calculated based on a past frame image.

  Next, an example of the flow of block information generation processing executed in step S132 of FIG. 14 will be described with reference to the flowchart of FIG.

  When the block information generation process is started, the processing target slice area specifying unit 141 specifies the area of the processing target slice in step S151.

  In order to know the area of the slice to be processed, it is known by knowing the macroblock contained in the slice and then knowing the pixels contained in the macroblock. The processing target slice area specifying unit 141 obtains the first macroblock address of the slice from the slice header.

  Here, the head macroblock address is a number assigned to the macroblock in the raster scan order from the upper left of the screen. As shown in FIG. 5, the macro block address at the upper left of the image (frame 151) is 0. Since slice 0 starts from the upper left of the frame 151, the macroblock address of the first macroblock 156-1 of slice 0 is 0. According to this order, the macroblock address of the last macroblock 156-2 of slice 0 is set to E0. Similarly to slice 0, the macroblock address of the first macroblock 157-1 of slice 1 is S1, and the macroblock address of the last macroblock 157-2 is E1. Furthermore, the macroblock address of the first macroblock 158-1 of slice 2 is set to S2, and the macroblock address of the last macroblock 158-2 is set to E2.

  When the slice is decoded, one macroblock address is added every time decoding processing of one macroblock is completed, and eventually the final macrobook of the slice is reached. A flag which is the last macroblock of the slice is set in the last macroblock. As a result, all the macroblock addresses held by the slice can be known. That is, from the first macro block address to the last macro block address.

  By the way, the image size of one frame is indicated by the number of macroblocks in the sequence parameter set (SPS (Sequence Parameter Set)) of the AVC stream (image compression information). pic_height_in_map_units_minus1 indicates the number of macroblocks in the vertical direction of the image. pic_width_in_mbs_minus1 indicates the number of macroblocks in the horizontal direction of the image.

  Therefore, the position of the macro block from the macro block address is expressed by the following equations (2) and (3).

mbx = macro block address% pic_width_in_mbs_minus1 (2)
mby = floor [macro block address / pic_width_in_mbs_minus1] (3)

  In Expression (2) and Expression (3), mbx indicates the number of the macroblock from the left, and mby indicates the number of the macroblock from the top. Further, floor [z] rounds down the decimal part of z to an integer, and A% B indicates the remainder obtained by dividing A by B.

  If the size of the macroblock is determined to be 16 × 16 pixels, the vertical and horizontal positions of the upper left pixel of the macroblock are (16 × mbx, 16 × mby) and are included in the macroblock. The pixel is a pixel included in a range of 16 pixels downward from the pixel position at the upper left and 16 pixels rightward. Up to this point, all the pixels of the slice are known. That is, the area of the processing target slice is specified.

  In step S152 in FIG. 15, the ALF block setting unit 142 determines the ALF block size. In step S153, the ALF block setting unit 142 determines the number of ALF blocks in the frame. Since the image size of the frame is determined in advance, when the ALF block size is determined, the number of ALF blocks (number of ALF blocks in the frame) necessary to spread the ALF blocks with the upper left of the frame as the reference point is also calculated. be able to. Since the set values for the vertical size (number of pixels) and the horizontal size (number of pixels) of the ALF block are prepared in advance, the ALF block setting unit 142 determines the size of each ALF block and the ALF block according to the set values. The number is determined and an ALF block is placed on the decoded image.

  The number of ALF blocks is calculated by the following formulas (4) and (5).

num_alf_block_x = floor [(16 × (pic_width_in_mbs_minus1 + 1) + (alf_block_size−1))
/ Alf_block_size] (4)
num_alf_block_y = floor [(16 × (pic_height_in_map_units_minus1 + 1)
+ (Alf_block_size−1)) / alf_block_size] (5)

  In Expression (4) and Expression (5), num_alf_block_x and num_alf_block_y are the horizontal and vertical numbers of ALF blocks included in the image, respectively. Alf_block_size indicates the size of one side of the ALF block. Here, for simplification of description, the ALF block is assumed to be a square. Of course, the vertical size and the horizontal size of the ALF block may be different from each other.

  In step S154, the offset processing unit 143 obtains the offset value of the ALF block 152 so that the boundary of the ALF block 152 is aligned with the end of the processing target slice. In step S155, the offset processing unit 143 moves the ALF block 152 according to the offset value calculated by the process in step S154. By this movement, the boundary of the ALF block 152 coincides with the end of the slice to be processed. The following processing is performed using the appropriately moved ALF block 152.

  In step S156, the processing target ALF block area specifying unit 144 determines a processing target ALF block. In step S157, the processing target ALF block area specifying unit 144 specifies the area of the processing target ALF block.

  The position of the i-th ALF block is expressed by the following equations (6) and (7).

alf_block_x = i% (num_alf_block_x−1) (6)
alf_block_y = floor [i / (num_alf_block_x−1)] (7)

  In Expression (6) and Expression (7), alf_block_x and alf_block_y indicate the number of the i-th ALF block in the horizontal direction and the vertical direction, respectively. The position of the upper left pixel of the i-th ALF block is a position obtained by multiplying each of alf_block_x and alf_block_y by alf_block_size. That is, the horizontal direction is 16 × alf_block_x, and the vertical direction is 16 × alf_block_y. Therefore, the area of the i-th ALF block is a range of alf_block_size × alf_block_size from the upper left pixel.

  In step S158, the determination unit 145 determines whether or not the area of the processing target slice is included in the area of the processing target ALF block specified as described above.

  If it is determined that the area of the processing target slice is included in the area of the processing target ALF block, the process proceeds to step S159. In step S159, the filter block flag generation unit 146 generates a filter block flag for the ALF block because the processing target ALF block is an ALF block necessary for the processing target slice. In step S160, the filter block flag generation unit 146 outputs the generated filter block flag.

  When the process of step S160 ends, the process proceeds to step S161. If it is determined in step S158 that the area of the processing target slice is not included in the area of the processing target ALF block, the ALF block is unnecessary for the processing target slice, and the process proceeds to step S161.

  In step S161, the processing target ALF block area specifying unit 144 determines whether or not all intra-frame ALF blocks have been processed. If it is determined that processing has not been performed, the process returns to step S156 to process a new ALF block. Repeat the process after that. Each time the loop processing is repeated, the processing target ALF block area specifying unit 144 performs raster scanning from the ALF block as the processing target ALF block, for example, from the upper left ALF block as a processing target ALF block. Select one by one in order.

  If it is determined in step S161 that all the intra-frame ALF blocks have been processed, the block information generation process ends, the process returns to step S132 in FIG. 14, the control information generation process ends, and the process proceeds to step S110 in FIG. Returning, the process after step S111 is performed.

  In the above description, when the ALF block is arranged so as to cover the frame image area, the upper left corner of the frame is used as the origin, but the position of the origin is arbitrary. For example, it may be the lower left, lower right, upper right, or center of the frame. However, the position of the origin and the way of arranging the ALF blocks need to be determined in advance so as to be common to the encoding process and the decoding process.

  In the above description, the order in which the processing target ALF blocks are selected is described as the raster scan order from the upper left, but the selection order and the start position are arbitrary.

  Next, an example of the flow of adaptive filter processing executed in step S111 in FIG. 11 will be described with reference to the flowchart in FIG.

  When the adaptive filter process is started, the decoded image of the processing target slice is supplied to the adaptive filter 172 and the selection unit 173. In step S171, the control unit 171 specifies the area of the processing target slice. As in the case of the process of step S151 in FIG. 12, the control unit 171 acquires the head macroblock address of the slice in the slice header, detects a flag indicating the last macroblock, and determines the last macroblock address from the head macroblock address. The area up to the macro block address is specified as the area of the processing target slice.

  In step S 172, the control unit 171 acquires the filter coefficient generated by the control information generation unit 112 and sets the filter coefficient in the adaptive filter 172. In step S173, the control unit 171 acquires the ALF block size determined by the control information generation unit 112, and sets (places) the ALF block having the ALF block size over the entire frame area.

  In step S174, the control unit 171 acquires the offset value generated by the control information generation unit 112, and appropriately moves the position of the ALF block set in step S173 according to the offset value (updates the position).

  In step S175, the control unit 171 selects one of the unprocessed ALF blocks from the ALF block group appropriately moved as described above as the processing target ALF block as in the case of step S156 in FIG. decide. The selection order of the ALF blocks is determined in advance and is the same as the selection order in the control information generation unit 112.

  In step S176, the control unit 171 specifies the determined area of the processing target ALF block as in the case of step S157 in FIG.

  In step S177, the control unit 171 determines whether the region of the processing target slice is included in the region of the processing target ALF block, as in the case of step S158 of FIG. If it is determined that it is included, the process proceeds to step S178.

  In step S178, the control unit 171 acquires the filter block flag of the processing target ALF block generated by the control information generation unit 112. Since the control information generation unit 112 generates the filter block flag as described above, actually, the filter block flag is supplied only for the ALF block including the area of the processing target slice. Since the processing order of the ALF block is common to the control information generation unit 112, the filter block flag is supplied in the processing order of the ALF block. Therefore, the control unit 171 can acquire (adopt) the filter block flag of the processing target ALF block by acquiring (adopting) the filter block flag in the supply order.

  Note that the supply timing of the filter block flag and the acquisition timing of the filter block flag by the control unit 171 do not have to coincide with each other. That is, the control unit 171 temporarily holds the filter block flag supplied from the control information generation unit 112, for example, in a built-in buffer or the like, and reads the filter block flag from the buffer in the process of step S178. Also good. Even in this case, the control unit 171 simply sets the reading order of the filter block flag to be the same as the order supplied from the control information generating unit 112, that is, the order of accumulation in the buffer. A filter block flag can be obtained.

  In step S179, the control unit 171 determines whether or not the value of the filter block flag is 1. When the value of the filter block flag is 1 and it is instructed to perform the filter process on the area of the processing target ALF block, the process proceeds to step S180. In step S180, the adaptive filter 172 is controlled by the control unit 171 to perform filter processing on the processing target ALF block. When the process of step S180 ends, the process proceeds to step S181. In this case, the selection unit 173 selects the output of the adaptive filter 172 under the control of the control unit 171 in step S181 and outputs it to the frame memory 114. That is, the decoded image (partial region) that has been subjected to the filter process is accumulated in the frame memory 114. When the process of step S181 ends, the process proceeds to step S182.

  In step S179, when the value of the filter block flag is 0, and it is instructed not to perform the filter process for the area of the processing target ALF block, the process of step S180 is omitted, and the process proceeds to step S181. In this case, the selection unit 173 is controlled by the control unit 171 to select the output of the deblocking filter 111 and outputs it to the frame memory 114 in step S181. That is, the decoded image (part of the region) that has not been filtered is accumulated in the frame memory 114. When the process of step S181 ends, the process proceeds to step S182.

  If it is determined in step S177 that the area of the processing target slice is not included in the area of the processing target ALF block, the processing target ALF block is an ALF block unrelated to the processing target slice. The process of step S181 is omitted, and the process proceeds to step S182.

  In step S182, the control unit 171 determines whether or not all intra-frame ALF blocks have been processed. If it is determined that there is an unprocessed ALF block, the process returns to step S175, and the subsequent processing is repeated for the new process target ALF block. Each time this loop processing is repeated, the control unit 171 selects ALF blocks from the group of ALF blocks spread in the frame area as processing target ALF blocks one by one in the raster scan order from the upper left ALF block. .

  If it is determined in step S182 that all of the ALF blocks in the frame have been processed, the adaptive filter process is terminated, the process returns to step S111 in FIG. 11, and the processes after step S112 are performed.

  As described above, the adaptive filter processing unit 113 adjusts the position of the ALF block 152 based on the offset value set so that the filter processing result is improved, for example, to align the boundary of the ALF block 152 with the end of the slice. Move. Thereby, the adaptive filter processing unit 113 can reduce the number of ALF blocks including the boundary of the slice. As a result, the image encoding device 100 can facilitate the filtering process and suppress an increase in the delay time. Furthermore, the image encoding device 100 can suppress a reduction in the effect of the filter processing.

  Further, the control information generation unit 112 generates an offset value for moving the ALF block 152 so that the boundary of the ALF block 152 is aligned with the edge of the slice, thereby adding a filter added to the image compression information. The number of bits of the block flag can be reduced. As a result, the image encoding device 100 can suppress a decrease in encoding efficiency.

  In addition, the control information generation unit 112 generates the offset value, so that the adaptive filter processing unit 113 moves the ALF blocks so as to reduce the number of ALF blocks including the slice boundaries as described above. it can.

  Note that by performing the adaptive filter processing as described above, the adaptive filter processing unit 113 can filter blocks of some ALF blocks in the frame that are necessary for the processing target slice among the plurality of slices formed in the frame. Based on the flag, it is possible to appropriately execute the filtering process on the processing target slice. As a result, the adaptive filter processing unit 113 can reduce block distortion that cannot be removed by the deblocking filter and distortion due to quantization of the processing target slice.

  The arrangement method (initial arrangement position) of the ALF block is predetermined. Therefore, in a state where the ALF blocks are arranged so as to be spread over the entire frame (initial state), the position of each ALF block can be easily obtained from the ALF block size. Therefore, as before, when filter block flags are generated for all ALF blocks in a frame and the ALF block is not moved, the position of the area corresponding to each filter block flag can be easily specified.

  However, for example, in the case of a multi-slice in which a plurality of slices are configured in a frame, it is conceivable to control the filter processing for the processing target slice using the filter block flags of some ALF blocks in the frame. In such a case, the position of the region corresponding to the filter block flag to be used differs depending on the position of the region of the processing target slice (that is, whether the processing target slice is a plurality of slices in the frame).

  In addition, as described above, the ALF block may be moved according to the offset value.

  However, the conventional technique does not specify the position of the processing target slice or the filter block flag. Therefore, the control by the filter block flag generated in the control information generation unit 112 does not work properly, and the adaptive filter processing may not be performed properly.

  As described above, the adaptive filter processing unit 113 identifies the position of the area of the slice to be processed, which is a partial area in the frame, and the position of the area corresponding to the filter block flag of the partial ALF block in the frame. Therefore, adaptive filter processing can be performed correctly. That is, since the filter block flag that does not affect the processing target slice of the ALF block that does not include the processing target slice area becomes unnecessary, the adaptive filter processing unit 113 suppresses the reduction in the encoding efficiency of the image compression information. be able to.

  Further, as described above, the control information generation unit 112 generates the filter block flag only for the ALF block including the region of the processing target slice, and thus suppresses the generation of an unnecessary filter block flag and encodes the image compression information. Reduction of the conversion efficiency can be suppressed.

  Furthermore, as described above, the adaptive filter processing unit 113 uses the same method as the control information generation unit 112 to specify the position of the region of the processing target slice and the position of the region corresponding to the filter block flag. It can be done easily.

  Further, the lossless encoding unit 106 adds block information including an ALF block size, an offset value, and a filter block flag to the encoded data (for example, embeds it in a slice header), thereby decoding the encoded data. Also in the apparatus, similar to the case of the adaptive filter processing unit 113, filter processing based on block information can be performed. For example, ALF blocks can be moved to reduce the number of ALF blocks that include slice boundaries.

  Here, “add” indicates that block information is associated with encoded data in an arbitrary form. For example, it may be described as a syntax of encoded data or may be described as user data. Further, block information may be linked to encoded data as metadata. That is, “addition” includes “embedding”, “description”, “multiplexing”, “concatenation”, and the like.

  By performing the encoding process with the block information generation process and the adaptive filter process as described above, the image encoding apparatus 100 can more appropriately perform local control of the filter process at the time of encoding or decoding. it can.

<2. Second Embodiment>
[Device Configuration]
Next, an image decoding apparatus corresponding to the image encoding apparatus 100 described in the first embodiment will be described. FIG. 17 is a block diagram illustrating a configuration example of an embodiment of an image decoding device as an image processing device to which the present invention has been applied.

  The image decoding device 200 decodes the image compression information output from the image encoding device 100 and generates a decoded image.

  The image decoding apparatus 200 includes a storage buffer 201, a lossless decoding unit 202, an inverse quantization unit 203, an inverse orthogonal transform unit 204, a calculation unit 205, and a deblocking filter 206. Further, the image decoding apparatus 200 includes an adaptive filter processing unit 207. Furthermore, the image decoding apparatus 200 includes a screen rearrangement buffer 208 and a D / A (Digital / Analog) conversion unit 209. In addition, the image decoding device 200 includes a frame memory 210, an intra prediction unit 211, a motion compensation unit 212, and a selection unit 213.

  The accumulation buffer 201 accumulates transmitted image compression information. The lossless decoding unit 202 decodes the information supplied from the accumulation buffer 201 and encoded by the lossless encoding unit 106 in FIG. 1 by a method corresponding to the encoding method of the lossless encoding unit 106.

  When the macroblock is intra-coded, the lossless decoding unit 202 decodes the intra prediction mode information stored in the header portion of the image compression information and transmits the information to the intra prediction unit 211. If the macroblock is inter-coded, the lossless decoding unit 202 decodes the motion vector information stored in the header portion of the image compression information and transfers the information to the motion compensation unit 212.

  Further, the lossless decoding unit 202 extracts and decodes control information for adaptive filter (control information generated by the control information generation unit 112) from the slice header of the image compression information, and decodes the information to the adaptive filter processing unit 207. To supply.

  The inverse quantization unit 203 inversely quantizes the image decoded by the lossless decoding unit 202 by a method corresponding to the quantization method of the quantization unit 105 in FIG. The inverse orthogonal transform unit 204 performs inverse orthogonal transform on the output of the inverse quantization unit 203 by a method corresponding to the orthogonal transform method of the orthogonal transform unit 104 in FIG.

  The calculation unit 205 adds the predicted image supplied from the selection unit 213 to the difference information subjected to inverse orthogonal transform, and generates a decoded image. The deblocking filter 206 removes block distortion of the decoded image generated by the addition process.

  The adaptive filter processing unit 207 is an image supplied from the deblocking filter 206 based on information such as a filter coefficient, an ALF block size, an offset value, and a filter block flag included in the control information supplied from the lossless decoding unit 202. Filter processing for. The adaptive filter processing unit 207 performs the same adaptive filter processing as the adaptive filter processing unit 113 in FIG. As a result, the adaptive filter processing unit 207 can reduce block distortion that cannot be removed by the deblocking filter 206 and distortion due to quantization.

  The adaptive filter processing unit 207 supplies the filtered image to the frame memory 210, accumulates it as reference image information, and outputs it to the screen rearrangement buffer 208.

  The screen rearrangement buffer 208 rearranges images. That is, the order of frames rearranged for the encoding order by the screen rearrangement buffer 102 in FIG. 1 is rearranged in the original display order. The D / A conversion unit 209 performs D / A conversion on the image supplied from the screen rearrangement buffer 208 and outputs it. For example, the D / A conversion unit 209 outputs an output signal obtained by D / A conversion to a display (not shown) to display an image.

  The intra prediction unit 211 generates a prediction image based on the information supplied from the lossless decoding unit 202 and outputs the generated prediction image to the selection unit 213 when the frame is intra-coded. .

  When the frame is inter-encoded, the motion compensation unit 212 performs motion compensation processing on the reference image information stored in the frame memory 210 based on the motion vector information supplied from the lossless decoding unit 202. Do.

  When the macroblock is an intra-coded block, the selection unit 213 connects to the intra prediction unit 211 and supplies the image supplied from the intra prediction unit 211 to the calculation unit 205 as a predicted image. When the macroblock is inter-coded, the selection unit 213 connects to the motion compensation unit 212 and supplies the image supplied from the motion compensation unit 212 to the calculation unit 205 as a predicted image.

[Process flow]
An example of the flow of decoding processing executed by the image decoding device 200 will be described with reference to the flowchart of FIG.

  In step S201, the accumulation buffer 201 accumulates the transmitted image. In step S202, the lossless decoding unit 202 decodes the compressed image supplied from the accumulation buffer 201. That is, the I picture, P picture, and B picture encoded by the lossless encoding unit 106 in FIG. 1 are decoded.

  At this time, motion vector information, reference frame information, prediction mode information (information indicating an intra prediction mode or an inter prediction mode), and the like are also decoded.

  That is, when the prediction mode information is intra prediction mode information, the prediction mode information is supplied to the intra prediction unit 211. When the prediction mode information is inter prediction mode information, motion vector information and reference frame information corresponding to the prediction mode information are supplied to the motion compensation unit 212.

  In step S202, the lossless decoding unit 202 extracts control information for adaptive filter processing from the slice header of the image compression information and decodes it. The decoded control information is supplied to the adaptive filter processing unit 207.

  In step S204, the inverse quantization unit 203 inversely quantizes the transform coefficient decoded in step S202 with a characteristic corresponding to the characteristic of the quantization unit 105 in FIG. In step S205, the inverse orthogonal transform unit 204 performs inverse orthogonal transform on the transform coefficient inversely quantized by the process in step S204 with characteristics corresponding to the characteristics of the orthogonal transform unit 104 in FIG. As a result, the difference information corresponding to the input of the orthogonal transform unit 104 (output of the calculation unit 103) in FIG. 1 is decoded.

  In step S206, the calculation unit 205 adds the prediction image selected in the process of step S212 described later to the difference information. As a result, the original image is decoded. In step S207, the deblocking filter 206 filters the image output from the calculation unit 205. Thereby, block distortion is removed.

  In step S208, the adaptive filter processing unit 207 further performs adaptive filter processing on the image that has been subjected to deblocking filter processing. This adaptive filter processing is the same as the processing performed by the adaptive filter processing unit 113 in FIG. That is, this adaptive filter process is performed in the same manner as described with reference to the flowchart of FIG. 16 except that the control information supplied from the lossless decoding unit 202 is used. However, the control information supplied from the lossless decoding unit 202 is also generated by the control information generation unit 112 in FIG. 1 and is substantially used by the adaptive filter processing unit 113 in FIG. 1. This is equivalent to the control information supplied by the user.

  By this adaptive filter processing, it is possible to reduce block distortion and quantization distortion that could not be removed by deblocking filter processing.

  In step S209, the frame memory 210 stores the filtered image.

  When the intra prediction mode information is supplied, the intra prediction unit 211 performs an intra prediction process in the intra prediction mode in step S210. When inter prediction mode information is supplied, the motion compensation unit 212 performs inter prediction mode motion compensation processing in step S211.

  In step S212, the selection unit 213 selects a predicted image. That is, one of the prediction image generated by the intra prediction unit 211 or the prediction image generated by the motion compensation unit 212 is selected, and the selected prediction image is supplied to the calculation unit 205.

  For example, in the case of an intra-coded image, the selection unit 213 selects the prediction image generated by the intra prediction unit 211 and supplies the selected prediction image to the calculation unit 205. In the case of an inter-coded image, the selection unit 213 selects the predicted image generated by the motion compensation unit 212 and supplies the selected prediction image to the calculation unit 205.

  In step S213, the screen rearrangement buffer 208 performs rearrangement. That is, the order of frames rearranged for encoding by the screen rearrangement buffer 102 of the image encoding device 100 in FIG. 1 is rearranged in the original display order.

  In step S214, the D / A converter 209 D / A converts the image from the screen rearrangement buffer 208. This image is output to a display (not shown), and the image is displayed.

  As described above, in the image decoding device 200, the lossless decoding unit 202 extracts and decodes the control information supplied from the image encoding device 100, and the adaptive filter processing unit 207 uses the control information to decode the image code. The adaptive filter processing is performed in the same manner as the adaptive filter processing unit 113 of the conversion apparatus 100.

  That is, the adaptive filter processing unit 207 moves the position of the ALF block based on the offset value so that the boundary of the ALF block is aligned with the end of the slice. Thereby, the adaptive filter processing unit 207 can reduce the number of ALF blocks including slice boundaries. As a result, the image decoding apparatus 200 can make the filtering process easier and suppress an increase in delay time. Furthermore, the image decoding apparatus 200 can suppress a reduction in the effect of the filter processing.

  In addition, by performing adaptive filter processing as described above, the adaptive filter processing unit 207 allows filter blocks of some ALF blocks in the frame that are necessary for the processing target slice among the plurality of slices formed in the frame. Based on the flag, it is possible to appropriately execute the filtering process on the processing target slice. As a result, the adaptive filter processing unit 207 can reduce block distortion that cannot be removed by the deblocking filter and distortion due to quantization of the slice to be processed.

  That is, as in the case of the adaptive filter processing unit 113, the adaptive filter processing unit 207 appropriately executes filter processing on the processing target slice based on the filter block flag supplied only for the ALF block necessary for the processing target slice. can do.

  Therefore, the image decoding apparatus 200 can more appropriately perform local control of filter processing at the time of encoding or decoding.

<3. Third Embodiment>
[Other examples of ALF blocks to be processed]
In the above, the control information generation unit 112 generates a filter block flag for all ALF blocks including even a region of the processing target slice, and the adaptive filter processing unit 113 includes an ALF including the region of the processing target slice. It has been described that all blocks are filtered.

  However, for example, if the ALF block includes only one pixel of the processing target slice, the filter processing hardly affects the image quality of the processing target slice. As described above, even if the filtering process is performed on the ALF block having a small area ratio of the processing target slice, a sufficient effect cannot be obtained, and the processing (load) may be wasted.

  Thus, only ALF blocks that include a predetermined percentage or more of the area of the processing target slice may be set as processing targets. The predetermined ratio serving as the threshold is arbitrary. Further, this value may be determined in advance or may be variable according to the content of the image.

[Process flow]
An example of the flow of block information generation processing in this case will be described with reference to the flowchart of FIG. The flowchart of FIG. 19 corresponds to the flowchart of FIG.

  That is, as shown in FIG. 19, in this case as well, the block information generation process is performed basically in the same manner as described with reference to FIG.

  Therefore, the configuration of the control information generation unit 112 in this case is the same as that in FIG.

  Each process of step S351 thru | or step S357 of FIG. 19 is performed similarly to each process of step S151 thru | or step S157 of FIG.

  However, in the case of FIG. 19, when the area of the processing target ALF block is specified, in step S358, the determination unit 145 determines whether or not a predetermined ratio or more of the area of the processing target ALF block is the area of the processing target slice. Determine whether.

  When a predetermined ratio or more of the area of the processing target ALF block is the area of the processing target slice, the process proceeds to step S359. In step S358, if the area of the processing target slice included in the area of the processing target ALF block is less than the predetermined ratio, the process proceeds to step S361.

  Each process of step S359 thru | or step S361 is performed similarly to each process of step S159 thru | or step S161 of FIG.

  As described above, the condition for generating the filter block flag can be further limited to a substantially useful range as compared with the case of the first embodiment. Thereby, the image coding apparatus 100 and the image decoding apparatus 200 can further suppress a reduction in coding efficiency.

  In the above, the processing unit of the encoding process and the decoding process using the adaptive filter is the slice unit. However, the present invention is not limited to this, and any data unit smaller than the frame unit may be used.

<4. Fourth Embodiment>
[Other examples of control information update]
In the above description, it has been explained that the local control of the filter processing at the time of encoding or decoding is performed more appropriately by moving the ALF block so as to align with the edge of the slice. Other methods may be used for more appropriate control. For example, the ALF block may be moved to another destination, or the ALF block size may be updated. Furthermore, the filter coefficient may be optimized in accordance with the control information update.

[Other movement examples]
The ALF block may be moved based on the texture change (image content). FIG. 20 is a diagram for explaining an example of the offset of the ALF block with respect to the texture change.

  For example, as shown in FIG. 20A, it is assumed that there are texture regions (region 401 and region 402) having different characteristics in the frame 400 of the image to be encoded. As shown in FIG. 20A, the region 401 is a vertical striped texture, and the region 402 is a horizontal striped texture. Therefore, the optimum filter characteristics for the region 401 and the region 402 are different from each other.

  When the ALF block 404 is arranged in such a frame 400, for example, as shown in FIG. 20B, the texture boundary 403 (tangent line between the region 401 and the region 402) and the boundary between the ALF block 404 (the boundary 404A and the boundary 404B). ) May be off. In such a case, the ALF block including the texture boundary 403 includes images having different characteristics in the region. That is, the ALF block including the texture boundary 403 is greatly different from the ALF block including only the region 401 and the ALF block including only the region 402 in this way, and the image quality may be strongly deteriorated by the filter processing. There is.

  For example, if the filter coefficient is matched with the texture characteristics of the area 401 and only the ALF block including the area 401 is filtered, the ALF block including the texture boundary 403 by the part of the area 402 not corresponding to the filter coefficient. There was a risk that the image quality of the image would be reduced. Conversely, the same applies to the case where the filter coefficient is matched with the texture characteristics of the region 402 and only the ALF block including the region 402 is subjected to the filtering process.

  From the above, it has been impossible to perform filtering on the ALF block including the texture boundary 403.

  Therefore, as shown in FIG. 20C, the control information generation unit moves the ALF block, calculates an offset value so that the boundary 404B of the ALF block matches the boundary 403 of the texture, and the adaptive filter processing unit Based on the offset value, the ALF block may be moved so that the boundary 404B of the ALF block matches the boundary 403 of the texture.

  By doing so, as shown in FIG. 20C, the number of ALF blocks including the texture boundary 403 in the region can be reduced. Thereby, the image encoding device or the image decoding device can control the local filter processing so that a better filter result can be obtained.

[Example of single slice movement]
In the first embodiment, the case of multi-slice has been described, but the movement of the ALF block may be performed in the case of a single slice. For example, in FIG. 21A, the ALF block 404 is arranged with respect to the area of the frame indicated by the frame 411 using the upper left pixel 412 of the area as a reference point. In this arrangement, when a good value cannot be obtained as a result of the filter processing, the control information generation unit may move the ALF block 404 as shown in FIG. 21B.

  In the example of FIG. 21B, the ALF block 404 is aligned with the right end of the frame 411. As described above, by moving the position of the ALF block, the image encoding device or the image decoding device can perform local filter processing control so as to obtain a better filter result. Note that the destination (destination) in this case is arbitrary as long as a good value is obtained as a result of the filtering process.

[Update block size]
Further, the ALF block size may be updated. For example, when there is a horizontally long region made of the same texture as in the frame 420 shown in FIG. 22A, each ALF block is a plurality of ALF blocks 421 each having a square shape as shown in FIG. 22B. Since the texture is included, the effect of the filter processing may be reduced.

  Therefore, as shown in FIG. 22C, the control information generation unit may update the ALF block size according to the content of the image such as the texture structure. In the example of FIG. 22C, each ALF block 422 is set to a horizontally long rectangle in accordance with the texture structure. By doing in this way, the image coding apparatus or the image decoding apparatus can control local filter processing so that a better filter result can be obtained.

[Device Configuration]
FIG. 23 is a block diagram illustrating another configuration example of the control information generation unit 112.

  In this case, the control information generation unit 112 includes a setting unit 431, a generation unit 432, a calculation unit 433, and a determination unit 434.

  The setting unit 431 sets a filter coefficient, an ALF block size, and an offset value. The setting method of these parameters is arbitrary. For example, the setting is performed in the same manner as the method described in the first embodiment. In addition, candidate values may be prepared in advance. However, in any case, a plurality of parameters (candidate values or combinations thereof) are prepared.

  The setting unit 431 selects values one by one from a plurality of candidate values, and sets the filter coefficient, the vertical size and horizontal size of the ALF block, and the offset value.

  The generation unit 432 generates a filter block flag for each ALF block using each parameter set by the setting unit 431.

  The calculation unit 433 performs filter processing using each parameter set in the setting unit 431 while controlling using the filter block flag generated in the generation unit 432, and calculates a cost value for determining the filter processing result. To do.

  The setting unit 431 changes the value of each parameter, and the generation unit 432 and the calculation unit 433 perform processing, whereby a plurality of cost values based on different setting patterns are calculated.

  The determining unit 434 compares the plurality of cost values and adopts the setting pattern when the best result is obtained, determines the filter coefficient, the vertical and horizontal sizes of the ALF block, and the offset value, and outputs them. To do. The determination unit 434 also outputs the filter block flag at that time.

[Process flow]
Next, another example of the flow of control information generation processing will be described with reference to the flowchart of FIG. This control information generation process corresponds to the example described with reference to the flowchart of FIG. That is, this control information generation process is executed in step S110 of FIG.

  When the control information generation process is started, the setting unit 431 sets the filter coefficient, the vertical size and horizontal size of the ALF block, and the offset value in step S431. A plurality of candidate values for each parameter are generated or prepared. The setting unit 431 creates one setting pattern (a combination of values) by selecting each parameter value from a plurality of candidate values.

  When the value of each parameter is set, the generation unit 432 determines a processing target ALF block in step S432, and in step S433, the value of each processing target ALF block is determined from the value of each parameter set in step S431. Identify the area. The method for specifying this region is the same as the method described above in the first embodiment.

  In step S434, the generation unit 432 generates a filter block flag for the processing target ALF block. The method for generating the filter block flag is the same as the method described above in the first embodiment. When the filter block flag having the value “0” or the value “1” is generated, the generation unit 432 determines whether or not all intra-frame ALF blocks have been processed in step S435. If it is determined that there is an unprocessed ALF block, the process returns to step S432, and the subsequent processing is repeated.

  If it is determined in step S435 that all intra-frame ALF blocks have been processed, the process proceeds to step S436.

  In step S436, the calculation unit 433 calculates the cost value of the filter processing result. The cost function is calculated using, for example, the following equation (8) based on Lagrange's undetermined coefficient method.

J = D + λ × R (8)

  Here, J is a cost value, D is a distortion amount, R is a bit amount, and λ is an empirically obtained coefficient, which is often dependent on a quantization parameter at the time of encoding and a picture type. The cost value J is calculated using this equation.

  In step S437, the calculation unit 433 determines whether cost values have been calculated for all setting patterns. For example, it is determined that there are unselected candidate values for each parameter such as filter coefficients, ALF block vertical and horizontal sizes, and offset values, and cost values are not calculated for all setting patterns. In this case, the process returns to step S431, and the subsequent processing is repeated for the new setting pattern.

  As described above, Steps S431 to S437 are repeated, and if it is determined in Step S437 that the cost value has been calculated for all setting patterns, the process proceeds to Step S438.

  In step S438, the determination unit 434 compares the obtained plurality of cost values J, specifies a setting pattern that minimizes the cost value J, and sets the filter coefficient, the vertical and horizontal sizes of the ALF block, and the offset value. The setting pattern is determined.

  When the filter coefficient, the vertical size and horizontal size of the ALF block, and the offset value are determined, the determination unit 434 outputs these values in step S439.

  When the filter coefficient, the vertical size and horizontal size of the ALF block, and the offset value are output, the control information generation process ends, the process returns to step S110 in FIG. 11, and the processes after step S111 are performed.

  In this way, the control information generation unit 112 can optimize the values of control information such as filter coefficients, ALF block vertical and horizontal sizes, and offset values by calculating the cost value J. Of course, the value of the filter block flag can also be optimized.

  Thereby, the image coding apparatus 100 can perform local control of the filter process at the time of encoding more appropriately. In addition, the image encoding device 100 can encode each parameter of the control information determined in this way as in the case of the first embodiment, and include it in the slice header of the image compression information.

  By doing in this way, the image decoding apparatus 200 can perform an adaptive filter process using each of these parameters by performing a decoding process similarly to the case of the first embodiment. That is, the image encoding device 100 can cause the image decoding device 200 to more appropriately perform local control of the filter processing at the time of decoding. That is, the image decoding apparatus 200 can more appropriately perform local control of the filtering process at the time of decoding by performing the filtering process using the control information determined as described above by the image encoding apparatus 100. it can.

<5. Fifth embodiment>
[Description of QALF]
As shown in Non-Patent Document 3, the ALF block may have a quadtree structure. This technique is called QALF (Quad tree-based Adaptive Loop Filter). The quad tree structure is a hierarchical structure in which the area of one ALF block in the upper hierarchy in the lower hierarchy is divided into four.

  FIG. 25 shows an example in which ALF block division is expressed by a quadtree structure with a maximum number of layers of 3, and a filter block flag is designated for each ALF block.

  FIG. 25A shows layer 0, which is an ALF block that is the root of a quadtree structure. In the quad tree structure, each ALF block has a block partitioning flag indicating whether or not it is divided into four in the lower hierarchy. The value of the block partitioning flag of the ALF block shown in FIG. 25A is “1”. That is, this ALF block is divided into four in the lower hierarchy (layer 1). FIG. 25B shows the layer 1. That is, four ALF blocks are formed in layer 1.

  When the block partitioning flag is “0”, it is not divided into four in lower layers. That is, there is no further division, and a filter block flag is generated for the ALF block. That is, the ALF block whose block partitioning flag is “0” also has a filter block flag. “0” on the left of “0-1” shown in FIG. 25B indicates the block partitioning flag of the ALF block, and “1” on the right indicates the filter block flag of the ALF block.

  Two ALF blocks whose layer partitioning flag of layer 1 is “1” are further divided into four in a lower hierarchy (layer 2). FIG. 25C shows the layer 2. That is, 10 ALF blocks are formed in layer 2.

  Similarly, a filter block flag is also assigned to an ALF block whose block partitioning flag is “0” in layer 2. In FIG. 25C, the block partitioning flag of one ALF block is “1”. That is, the ALF block is divided into four in the lower hierarchy (layer 3). FIG. 25D shows the layer 3. That is, 13 ALF blocks are formed in layer 3.

  By forming a quad tree as shown in FIG. 25, the configuration of the ALF block finally becomes as shown in FIG. As described above, in the quadtree structure, the size of the ALF block is different for each hierarchy. That is, ALF blocks can have different sizes within a frame by adopting a quadtree structure.

  Control of the filter block flag in each ALF block is the same as in the case of the first embodiment. That is, the filter processing is not performed on the area of the ALF block (the hatched portion in FIG. 26) whose filter block flag value is “0”.

  The problem that the coding efficiency may be reduced in the case of multi-slice occurs when an ALF block is set in a slice area smaller than a frame. Therefore, the same problem occurs in QALF in which the expression of the ALF block is improved.

  FIG. 27 shows an example in which the area of slice 1 in FIG. 5 is encoded using the QALF technique. Here, the QALF block 511 is an ALF block formed in a quad tree structure, and the area of the bold line 521 indicates the area of the slice 1. In the case of FIG. 27, there are many QALF blocks 511 including slice boundaries (thick lines 521).

  Therefore, if the filtering process is performed as it is in the past, the encoding efficiency may be reduced, the filtering process may be complicated, the delay time may be increased, and the effect of the filtering process may be reduced. is there.

  Similarly to the case of BALF described in the first embodiment, the QALF block indicated by the hatched pattern in FIG. 27 is an unnecessary ALF block because it does not include the slice 1 region.

  If the filter block flag is also given to this unnecessary ALF block as in the prior art, the image compression information is unnecessarily increased, which may deteriorate the coding efficiency.

  In the case of QALF, the image coding apparatus 100 moves the QALF block 511 in the same manner as in the case of BALF described in the first to fourth embodiments, and obtains a better filter result. Can be made. For example, the image encoding device 100 embeds control information in a slice header based on a syntax as shown in FIG. As a result, the control information is also transmitted to the image decoding apparatus 200 as in the case of BALF.

  That is, the image encoding device 100 and the image decoding device 200 can more appropriately perform local control of filter processing at the time of encoding or decoding.

  Also, the image coding apparatus 100 suppresses generation of unnecessary filter block flags and does not include them in the slice header by the same method as in the case of BALF described in the first to fourth embodiments. It can also be done.

  That is, the image coding apparatus 100 and the image decoding apparatus 200 can recognize that the block with the diagonal line pattern illustrated in FIG. 27 does not include the slice (slice 1 in FIG. 27). Therefore, the image coding apparatus 100 generates a filter block flag only for the ALF block having the quad tree structure including the slice and supplies the generated filter block flag to the image decoding apparatus 200 together with the image compression information, thereby eliminating unnecessary filter blocks. The generation of the flag can be suppressed, and the decrease in encoding efficiency can be suppressed.

<6. Sixth Embodiment>
[Personal computer]
The series of processes described above can be executed by hardware or can be executed by software. In this case, for example, a personal computer as shown in FIG. 29 may be configured.

  29, the CPU 601 of the personal computer 600 executes various processes according to a program stored in a ROM (Read Only Memory) 602 or a program loaded from a storage unit 613 to a RAM (Random Access Memory) 603. The RAM 603 also appropriately stores data necessary for the CPU 601 to execute various processes.

  The CPU 601, ROM 602, and RAM 603 are connected to each other via a bus 604. An input / output interface 610 is also connected to the bus 604.

  The input / output interface 610 includes an input unit 611 including a keyboard and a mouse, a display including a CRT (Cathode Ray Tube) and an LCD (Liquid Crystal Display), an output unit 612 including a speaker, a hard disk, and the like. A communication unit 614 including a storage unit 613 and a modem is connected. The communication unit 614 performs communication processing via a network including the Internet.

  A drive 615 is connected to the input / output interface 610 as necessary, and a removable medium 621 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory is appropriately mounted, and a computer program read from them is loaded. It is installed in the storage unit 613 as necessary.

  When the above-described series of processing is executed by software, a program constituting the software is installed from a network or a recording medium.

  For example, as shown in FIG. 29, the recording medium is distributed to distribute the program to the user separately from the apparatus main body, and includes a magnetic disk (including a flexible disk) on which the program is recorded, an optical disk ( It only consists of removable media 621 consisting of CD-ROM (compact disc-read only memory), DVD (including digital versatile disc), magneto-optical disc (including MD (mini disc)), or semiconductor memory. Rather, it is composed of a ROM 602 storing a program and a hard disk included in the storage unit 613, which is distributed to the user in a state of being incorporated in the apparatus main body in advance.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  Further, in the present specification, the step of describing the program recorded on the recording medium is not limited to the processing performed in chronological order according to the described order, but may be performed in parallel or It also includes processes that are executed individually.

  Further, in the present specification, the system represents the entire apparatus composed of a plurality of devices (apparatuses).

  In addition, in the above description, the configuration described as one device (or processing unit) may be divided and configured as a plurality of devices (or processing units). Conversely, the configurations described above as a plurality of devices (or processing units) may be combined into a single device (or processing unit). Of course, a configuration other than that described above may be added to the configuration of each device (or each processing unit). Furthermore, if the configuration and operation of the entire system are substantially the same, a part of the configuration of a certain device (or processing unit) may be included in the configuration of another device (or other processing unit). . That is, the embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

  For example, the image encoding device 100 and the image decoding device 200 described above can be applied to any electronic device. Examples thereof will be described below.

<7. Seventh Embodiment>
[Television receiver]
FIG. 30 is a block diagram illustrating a main configuration example of a television receiver using the image decoding device 200 to which the present invention has been applied.

  A television receiver 1000 illustrated in FIG. 30 includes a terrestrial tuner 1013, a video decoder 1015, a video signal processing circuit 1018, a graphic generation circuit 1019, a panel drive circuit 1020, and a display panel 1021.

  The terrestrial tuner 1013 receives a broadcast wave signal of analog terrestrial broadcasting via an antenna, demodulates it, acquires a video signal, and supplies it to the video decoder 1015. The video decoder 1015 performs a decoding process on the video signal supplied from the terrestrial tuner 1013 and supplies the obtained digital component signal to the video signal processing circuit 1018.

  The video signal processing circuit 1018 performs predetermined processing such as noise removal on the video data supplied from the video decoder 1015 and supplies the obtained video data to the graphic generation circuit 1019.

  The graphic generation circuit 1019 generates video data of a program to be displayed on the display panel 1021, image data by processing based on an application supplied via a network, and the generated video data and image data to the panel drive circuit 1020. Supply. The graphic generation circuit 1019 generates video data (graphics) for displaying a screen used by the user for selecting an item and superimposing it on the video data of the program. A process of supplying data to the panel drive circuit 1020 is also appropriately performed.

  The panel drive circuit 1020 drives the display panel 1021 based on the data supplied from the graphic generation circuit 1019 and causes the display panel 1021 to display a program video and the various screens described above.

  The display panel 1021 includes an LCD (Liquid Crystal Display) or the like, and displays a program video or the like according to control by the panel drive circuit 1020.

  The television receiver 1000 also includes an audio A / D (Analog / Digital) conversion circuit 1014, an audio signal processing circuit 1022, an echo cancellation / audio synthesis circuit 1023, an audio amplification circuit 1024, and a speaker 1025.

  The terrestrial tuner 1013 acquires not only the video signal but also the audio signal by demodulating the received broadcast wave signal. The terrestrial tuner 1013 supplies the acquired audio signal to the audio A / D conversion circuit 1014.

  The audio A / D conversion circuit 1014 performs A / D conversion processing on the audio signal supplied from the terrestrial tuner 1013 and supplies the obtained digital audio signal to the audio signal processing circuit 1022.

  The audio signal processing circuit 1022 performs predetermined processing such as noise removal on the audio data supplied from the audio A / D conversion circuit 1014, and supplies the obtained audio data to the echo cancellation / audio synthesis circuit 1023.

  The echo cancellation / voice synthesis circuit 1023 supplies the voice data supplied from the voice signal processing circuit 1022 to the voice amplification circuit 1024.

  The audio amplifying circuit 1024 performs D / A conversion processing and amplification processing on the audio data supplied from the echo cancellation / audio synthesizing circuit 1023, adjusts to a predetermined volume, and then outputs the audio from the speaker 1025.

  Furthermore, the television receiver 1000 also includes a digital tuner 1016 and an MPEG decoder 1017.

  The digital tuner 1016 receives a broadcast wave signal of a digital broadcast (terrestrial digital broadcast, BS (Broadcasting Satellite) / CS (Communications Satellite) digital broadcast) via an antenna, demodulates, and MPEG-TS (Moving Picture Experts Group). -Transport Stream) and supply it to the MPEG decoder 1017.

  The MPEG decoder 1017 cancels the scramble applied to the MPEG-TS supplied from the digital tuner 1016, and extracts a stream including program data to be played back (viewing target). The MPEG decoder 1017 decodes the audio packet constituting the extracted stream, supplies the obtained audio data to the audio signal processing circuit 1022, decodes the video packet constituting the stream, and converts the obtained video data into the video This is supplied to the signal processing circuit 1018. Also, the MPEG decoder 1017 supplies EPG (Electronic Program Guide) data extracted from the MPEG-TS to the CPU 1032 via a path (not shown).

  The television receiver 1000 uses the above-described image decoding device 200 as the MPEG decoder 1017 for decoding video packets in this way. Note that MPEG-TS transmitted from a broadcasting station or the like is encoded by the image encoding device 100.

  As in the case of the image decoding apparatus 200, the MPEG decoder 1017 moves the position of the ALF block based on the offset value so as to align the boundary of the ALF block with the end of the slice. As a result, the MPEG decoder 1017 can reduce the number of ALF blocks including slice boundaries. As a result, the MPEG decoder 1017 can more appropriately perform local control of filter processing.

  The video data supplied from the MPEG decoder 1017 is subjected to predetermined processing in the video signal processing circuit 1018 as in the case of the video data supplied from the video decoder 1015, and the generated video data in the graphic generation circuit 1019. Are appropriately superimposed and supplied to the display panel 1021 via the panel drive circuit 1020, and the image is displayed.

  The audio data supplied from the MPEG decoder 1017 is subjected to predetermined processing in the audio signal processing circuit 1022 as in the case of the audio data supplied from the audio A / D conversion circuit 1014, and an echo cancellation / audio synthesis circuit 1023. Are supplied to the audio amplifier circuit 1024 through which D / A conversion processing and amplification processing are performed. As a result, sound adjusted to a predetermined volume is output from the speaker 1025.

  The television receiver 1000 also includes a microphone 1026 and an A / D conversion circuit 1027.

  The A / D conversion circuit 1027 receives a user's voice signal captured by a microphone 1026 provided in the television receiver 1000 for voice conversation, and performs A / D conversion processing on the received voice signal. The obtained digital audio data is supplied to the echo cancellation / audio synthesis circuit 1023.

  When the audio data of the user (user A) of the television receiver 1000 is supplied from the A / D conversion circuit 1027, the echo cancellation / audio synthesis circuit 1023 performs echo cancellation on the audio data of the user A. The voice data obtained by combining with other voice data is output from the speaker 1025 via the voice amplifier circuit 1024.

  The television receiver 1000 further includes an audio codec 1028, an internal bus 1029, an SDRAM (Synchronous Dynamic Random Access Memory) 1030, a flash memory 1031, a CPU 1032, a USB (Universal Serial Bus) I / F 1033, and a network I / F 1034. .

  The A / D conversion circuit 1027 receives a user's voice signal captured by a microphone 1026 provided in the television receiver 1000 for voice conversation, and performs A / D conversion processing on the received voice signal. The obtained digital audio data is supplied to the audio codec 1028.

  The audio codec 1028 converts the audio data supplied from the A / D conversion circuit 1027 into data of a predetermined format for transmission via the network, and supplies the data to the network I / F 1034 via the internal bus 1029.

  The network I / F 1034 is connected to the network via a cable attached to the network terminal 1035. For example, the network I / F 1034 transmits the audio data supplied from the audio codec 1028 to another device connected to the network. In addition, the network I / F 1034 receives, for example, audio data transmitted from another device connected via the network via the network terminal 1035, and receives the audio data via the internal bus 1029 to the audio codec 1028. Supply.

  The audio codec 1028 converts the audio data supplied from the network I / F 1034 into data of a predetermined format, and supplies it to the echo cancellation / audio synthesis circuit 1023.

  The echo cancellation / speech synthesis circuit 1023 performs echo cancellation on the speech data supplied from the speech codec 1028, and synthesizes speech data obtained by combining with other speech data via the speech amplification circuit 1024. And output from the speaker 1025.

  The SDRAM 1030 stores various data necessary for the CPU 1032 to perform processing.

  The flash memory 1031 stores a program executed by the CPU 1032. The program stored in the flash memory 1031 is read by the CPU 1032 at a predetermined timing such as when the television receiver 1000 is activated. The flash memory 1031 also stores EPG data acquired via digital broadcasting, data acquired from a predetermined server via a network, and the like.

  For example, the flash memory 1031 stores MPEG-TS including content data acquired from a predetermined server via a network under the control of the CPU 1032. The flash memory 1031 supplies the MPEG-TS to the MPEG decoder 1017 via the internal bus 1029, for example, under the control of the CPU 1032.

  The MPEG decoder 1017 processes the MPEG-TS as in the case of the MPEG-TS supplied from the digital tuner 1016. In this way, the television receiver 1000 receives content data including video and audio via the network, decodes it using the MPEG decoder 1017, displays the video, and outputs audio. Can do.

  The television receiver 1000 also includes a light receiving unit 1037 that receives an infrared signal transmitted from the remote controller 1051.

  The light receiving unit 1037 receives infrared light from the remote controller 1051 and outputs a control code representing the content of the user operation obtained by demodulation to the CPU 1032.

  The CPU 1032 executes a program stored in the flash memory 1031 and controls the overall operation of the television receiver 1000 according to a control code supplied from the light receiving unit 1037. The CPU 1032 and each part of the television receiver 1000 are connected via a path (not shown).

  The USB I / F 1033 transmits and receives data to and from a device external to the television receiver 1000 connected via a USB cable attached to the USB terminal 1036. The network I / F 1034 is connected to the network via a cable attached to the network terminal 1035, and transmits / receives data other than audio data to / from various devices connected to the network.

  By using the image decoding apparatus 200 as the MPEG decoder 1017, the television receiver 1000 can more appropriately perform local control of filtering processing for broadcast wave signals received via an antenna and content data obtained via a network. Can be done.

<8. Eighth Embodiment>
[Mobile phone]
FIG. 31 is a block diagram illustrating a main configuration example of a mobile phone using an image encoding device and an image decoding device to which the present invention is applied.

  A mobile phone 1100 shown in FIG. 31 includes a main control unit 1150, a power supply circuit unit 1151, an operation input control unit 1152, an image encoder 1153, a camera I / F unit 1154, an LCD control, which are configured to control each unit in an integrated manner. Section 1155, image decoder 1156, demultiplexing section 1157, recording / reproducing section 1162, modulation / demodulation circuit section 1158, and audio codec 1159. These are connected to each other via a bus 1160.

  The mobile phone 1100 includes an operation key 1119, a CCD (Charge Coupled Devices) camera 1116, a liquid crystal display 1118, a storage unit 1123, a transmission / reception circuit unit 1163, an antenna 1114, a microphone (microphone) 1121, and a speaker 1117.

  When the end call and the power key are turned on by the user's operation, the power supply circuit unit 1151 starts up the mobile phone 1100 in an operable state by supplying power from the battery pack to each unit.

  The mobile phone 1100 transmits and receives voice signals, e-mails and image data, and images in various modes such as a voice call mode and a data communication mode based on the control of the main control unit 1150 including a CPU, a ROM, a RAM, and the like. Various operations such as shooting or data recording are performed.

  For example, in the voice call mode, the mobile phone 1100 converts the voice signal collected by the microphone (microphone) 1121 into digital voice data by the voice codec 1159, performs spectrum spread processing by the modulation / demodulation circuit unit 1158, and transmits and receives The unit 1163 performs digital / analog conversion processing and frequency conversion processing. The cellular phone 1100 transmits the transmission signal obtained by the conversion process to a base station (not shown) via the antenna 1114. The transmission signal (voice signal) transmitted to the base station is supplied to the mobile phone of the other party via the public telephone line network.

  Further, for example, in the voice call mode, the cellular phone 1100 amplifies the received signal received by the antenna 1114 by the transmission / reception circuit unit 1163, further performs frequency conversion processing and analog-digital conversion processing, and performs spectrum despreading processing by the modulation / demodulation circuit unit 1158. Then, the audio codec 1159 converts it into an analog audio signal. The cellular phone 1100 outputs an analog audio signal obtained by the conversion from the speaker 1117.

  Further, for example, when transmitting an e-mail in the data communication mode, the mobile phone 1100 receives e-mail text data input by operating the operation key 1119 in the operation input control unit 1152. The cellular phone 1100 processes the text data in the main control unit 1150 and displays it on the liquid crystal display 1118 as an image via the LCD control unit 1155.

  In addition, the mobile phone 1100 generates e-mail data in the main control unit 1150 based on text data received by the operation input control unit 1152, user instructions, and the like. The cellular phone 1100 performs spread spectrum processing on the e-mail data by the modulation / demodulation circuit unit 1158 and digital / analog conversion processing and frequency conversion processing by the transmission / reception circuit unit 1163. The cellular phone 1100 transmits the transmission signal obtained by the conversion process to a base station (not shown) via the antenna 1114. The transmission signal (e-mail) transmitted to the base station is supplied to a predetermined destination via a network and a mail server.

  Further, for example, when receiving an e-mail in the data communication mode, the mobile phone 1100 receives and amplifies the signal transmitted from the base station by the transmission / reception circuit unit 1163 via the antenna 1114, and further performs frequency conversion processing and Analog-digital conversion processing. The cellular phone 1100 performs spectrum despreading processing on the received signal by the modulation / demodulation circuit unit 1158 to restore the original e-mail data. The cellular phone 1100 displays the restored e-mail data on the liquid crystal display 1118 via the LCD control unit 1155.

  Note that the mobile phone 1100 can also record (store) the received e-mail data in the storage unit 1123 via the recording / playback unit 1162.

  The storage unit 1123 is an arbitrary rewritable storage medium. The storage unit 1123 may be, for example, a semiconductor memory such as a RAM or a built-in flash memory, a hard disk, or a removable disk such as a magnetic disk, a magneto-optical disk, an optical disk, a USB memory, or a memory card. It may be media. Of course, other than these may be used.

  Furthermore, for example, when transmitting image data in the data communication mode, the mobile phone 1100 generates image data with the CCD camera 1116 by imaging. The CCD camera 1116 has an optical device such as a lens and a diaphragm and a CCD as a photoelectric conversion element, images a subject, converts the intensity of received light into an electrical signal, and generates image data of the subject image. The CCD camera 1116 encodes the image data by the image encoder 1153 via the camera I / F unit 1154 and converts the encoded image data into encoded image data.

  The cellular phone 1100 uses the above-described image encoding device 100 as the image encoder 1153 that performs such processing. Accordingly, the image encoder 1053 can more appropriately perform local control of the filter processing, as in the case of the image encoding device 100.

  At the same time, the cellular phone 1100 converts the sound collected by the microphone (microphone) 1121 during imaging by the CCD camera 1116 from analog to digital at the audio codec 1159 and further encodes it.

  The cellular phone 1100 multiplexes the encoded image data supplied from the image encoder 1153 and the digital audio data supplied from the audio codec 1159 in a demultiplexing unit 1157 using a predetermined method. The cellular phone 1100 performs spread spectrum processing on the multiplexed data obtained as a result by the modulation / demodulation circuit unit 1158 and digital / analog conversion processing and frequency conversion processing by the transmission / reception circuit unit 1163. The cellular phone 1100 transmits the transmission signal obtained by the conversion process to a base station (not shown) via the antenna 1114. A transmission signal (image data) transmitted to the base station is supplied to a communication partner via a network or the like.

  When image data is not transmitted, the mobile phone 1100 can also display the image data generated by the CCD camera 1116 on the liquid crystal display 1118 via the LCD control unit 1155 without using the image encoder 1153.

  Further, for example, when receiving data of a moving image file linked to a simple homepage or the like in the data communication mode, the mobile phone 1100 transmits a signal transmitted from the base station to the transmission / reception circuit unit 1163 via the antenna 1114. Receive, amplify, and further perform frequency conversion processing and analog digital conversion processing. The cellular phone 1100 restores the original multiplexed data by subjecting the received signal to spectrum despreading processing by the modulation / demodulation circuit unit 1158. In the cellular phone 1100, the demultiplexing unit 1157 separates the multiplexed data and divides it into encoded image data and audio data.

  The cellular phone 1100 generates reproduced moving image data by decoding the encoded image data in the image decoder 1156, and displays it on the liquid crystal display 1118 via the LCD control unit 1155. Thereby, for example, the moving image data included in the moving image file linked to the simple homepage is displayed on the liquid crystal display 1118.

  The cellular phone 1100 uses the above-described image decoding device 200 as the image decoder 1156 that performs such processing. Therefore, as in the case of the image decoding device 200, the image decoder 1156 sets the position of the ALF block so that the boundary of the ALF block is aligned with the end of the slice based on the offset value supplied from the image encoding device 100. It is moved and adaptive filter control processing (and filter processing) is performed. As a result, the image decoder 1156 can more appropriately perform local control of the filter processing.

  At this time, the cellular phone 1100 simultaneously converts digital audio data into an analog audio signal in the audio codec 1159 and outputs the analog audio signal from the speaker 1117. Thereby, for example, audio data included in the moving image file linked to the simple homepage is reproduced.

  As in the case of e-mail, the mobile phone 1100 can record (store) the data linked to the received simplified home page in the storage unit 1123 via the recording / playback unit 1162. .

  Further, the mobile phone 1100 can analyze the two-dimensional code captured by the CCD camera 1116 and acquire information recorded in the two-dimensional code in the main control unit 1150.

  Further, the cellular phone 1100 can communicate with an external device by infrared rays at the infrared communication unit 1181.

  By using the image encoding device 100 as the image encoder 1153, the cellular phone 1100 can more appropriately perform local control of filter processing on encoded data generated by encoding image data generated by the CCD camera 1116, for example. It can be carried out.

  In addition, the cellular phone 1100 can more appropriately perform local control of filter processing on moving image file data linked to, for example, a simple homepage by using the image decoding device 200 as the image decoder 1156. .

  In the above description, the mobile phone 1100 is described as using the CCD camera 1116. However, instead of the CCD camera 1116, an image sensor (CMOS image sensor) using a CMOS (Complementary Metal Oxide Semiconductor) is used. May be. Also in this case, the mobile phone 1100 can capture an image of a subject and generate image data of the image of the subject, as in the case where the CCD camera 1116 is used.

  In the above description, the mobile phone 1100 has been described. For example, PDA (Personal Digital Assistants), a smartphone, an UMPC (Ultra Mobile Personal Computer), a netbook, a notebook personal computer, and the like. As long as the device has a communication function, the image encoding device 100 and the image decoding device 200 can be applied to any device as in the case of the mobile phone 1100.

<9. Ninth Embodiment>
[Hard Disk Recorder]
FIG. 32 is a block diagram illustrating a main configuration example of a hard disk recorder using the image encoding device and the image decoding device to which the present invention is applied.

  A hard disk recorder (HDD recorder) 1200 shown in FIG. 32 receives audio data and video data of a broadcast program included in a broadcast wave signal (television signal) transmitted from a satellite or a ground antenna received by a tuner. This is an apparatus for storing in a built-in hard disk and providing the stored data to the user at a timing according to the user's instruction.

  The hard disk recorder 1200 can extract, for example, audio data and video data from broadcast wave signals, appropriately decode them, and store them in a built-in hard disk. Also, the hard disk recorder 1200 can acquire audio data and video data from other devices via a network, for example, decode them as appropriate, and store them in a built-in hard disk.

  Further, the hard disk recorder 1200, for example, decodes audio data and video data recorded on the built-in hard disk, supplies them to the monitor 1260, displays the image on the screen of the monitor 1260, and displays the sound from the speaker of the monitor 1260. Can be output. Further, the hard disk recorder 1200 decodes audio data and video data extracted from a broadcast wave signal acquired via a tuner, or audio data and video data acquired from another device via a network, for example. The image can be supplied to the monitor 1260, the image can be displayed on the screen of the monitor 1260, and the sound can be output from the speaker of the monitor 1260.

  Of course, other operations are possible.

  As illustrated in FIG. 32, the hard disk recorder 1200 includes a reception unit 1221, a demodulation unit 1222, a demultiplexer 1223, an audio decoder 1224, a video decoder 1225, and a recorder control unit 1226. The hard disk recorder 1200 further includes an EPG data memory 1227, a program memory 1228, a work memory 1229, a display converter 1230, an OSD (On Screen Display) control unit 1231, a display control unit 1232, a recording / playback unit 1233, a D / A converter 1234, And a communication unit 1235.

  In addition, the display converter 1230 includes a video encoder 1241. The recording / playback unit 1233 includes an encoder 1251 and a decoder 1252.

  The receiving unit 1221 receives an infrared signal from a remote controller (not shown), converts it into an electrical signal, and outputs it to the recorder control unit 1226. The recorder control unit 1226 is constituted by, for example, a microprocessor and executes various processes according to a program stored in the program memory 1228. At this time, the recorder control unit 1226 uses the work memory 1229 as necessary.

  The communication unit 1235 is connected to a network and performs communication processing with other devices via the network. For example, the communication unit 1235 is controlled by the recorder control unit 1226, communicates with a tuner (not shown), and mainly outputs a channel selection control signal to the tuner.

  The demodulator 1222 demodulates the signal supplied from the tuner and outputs the demodulated signal to the demultiplexer 1223. The demultiplexer 1223 separates the data supplied from the demodulation unit 1222 into audio data, video data, and EPG data, and outputs them to the audio decoder 1224, the video decoder 1225, or the recorder control unit 1226, respectively.

  The audio decoder 1224 decodes the input audio data and outputs it to the recording / playback unit 1233. The video decoder 1225 decodes the input video data and outputs it to the display converter 1230. The recorder control unit 1226 supplies the input EPG data to the EPG data memory 1227 for storage.

  The display converter 1230 encodes the video data supplied from the video decoder 1225 or the recorder control unit 1226 into, for example, NTSC (National Television Standards Committee) video data by the video encoder 1241 and outputs the encoded video data to the recording / reproducing unit 1233. The display converter 1230 converts the screen size of the video data supplied from the video decoder 1225 or the recorder control unit 1226 into a size corresponding to the size of the monitor 1260, and converts the video data to NTSC video data by the video encoder 1241. Then, it is converted into an analog signal and output to the display control unit 1232.

  The display control unit 1232 superimposes the OSD signal output from the OSD (On Screen Display) control unit 1231 on the video signal input from the display converter 1230 under the control of the recorder control unit 1226, and displays it on the monitor 1260 display. Output and display.

  The monitor 1260 is also supplied with the audio data output from the audio decoder 1224 after being converted into an analog signal by the D / A converter 1234. The monitor 1260 outputs this audio signal from a built-in speaker.

  The recording / playback unit 1233 includes a hard disk as a storage medium for recording video data, audio data, and the like.

  For example, the recording / reproducing unit 1233 encodes the audio data supplied from the audio decoder 1224 by the encoder 1251. The recording / playback unit 1233 encodes the video data supplied from the video encoder 1241 of the display converter 1230 by the encoder 1251. The recording / playback unit 1233 combines the encoded data of the audio data and the encoded data of the video data by a multiplexer. The recording / playback unit 1233 amplifies the synthesized data by channel coding, and writes the data to the hard disk via the recording head.

  The recording / playback unit 1233 plays back the data recorded on the hard disk via the playback head, amplifies it, and separates it into audio data and video data by a demultiplexer. The recording / playback unit 1233 uses the decoder 1252 to decode the audio data and the video data. The recording / playback unit 1233 performs D / A conversion on the decoded audio data and outputs it to the speaker of the monitor 1260. In addition, the recording / playback unit 1233 performs D / A conversion on the decoded video data and outputs it to the display of the monitor 1260.

  The recorder control unit 1226 reads the latest EPG data from the EPG data memory 1227 based on the user instruction indicated by the infrared signal from the remote controller received via the receiving unit 1221, and supplies it to the OSD control unit 1231. To do. The OSD control unit 1231 generates image data corresponding to the input EPG data, and outputs the image data to the display control unit 1232. The display control unit 1232 outputs the video data input from the OSD control unit 1231 to the display of the monitor 1260 for display. As a result, an EPG (electronic program guide) is displayed on the display of the monitor 1260.

  Also, the hard disk recorder 1200 can acquire various data such as video data, audio data, or EPG data supplied from other devices via a network such as the Internet.

  The communication unit 1235 is controlled by the recorder control unit 1226, acquires encoded data such as video data, audio data, and EPG data transmitted from another device via the network, and supplies the encoded data to the recorder control unit 1226. To do. For example, the recorder control unit 1226 supplies the encoded data of the acquired video data and audio data to the recording / playback unit 1233 and stores it in the hard disk. At this time, the recorder control unit 1226 and the recording / playback unit 1233 may perform processing such as re-encoding as necessary.

  Also, the recorder control unit 1226 decodes the acquired encoded data of video data and audio data, and supplies the obtained video data to the display converter 1230. Similar to the video data supplied from the video decoder 1225, the display converter 1230 processes the video data supplied from the recorder control unit 1226, supplies the processed video data to the monitor 1260 via the display control unit 1232, and displays the image. .

  In accordance with the image display, the recorder control unit 1226 may supply the decoded audio data to the monitor 1260 via the D / A converter 1234 and output the sound from the speaker.

  Further, the recorder control unit 1226 decodes the encoded data of the acquired EPG data, and supplies the decoded EPG data to the EPG data memory 1227.

  The hard disk recorder 1200 as described above uses the image decoding device 200 as a decoder incorporated in the video decoder 1225, the decoder 1252, and the recorder control unit 1226. Therefore, the decoder incorporated in the video decoder 1225, the decoder 1252, and the recorder control unit 1226, as in the case of the image decoding apparatus 200, matches the boundary of the ALF block to the end of the slice based on the offset value. Move the position of the ALF block. Thereby, the video decoder 1225, the decoder 1252, and the decoder built in the recorder control unit 1226 can more appropriately perform local control of the filter processing.

  Accordingly, the hard disk recorder 1200 more appropriately performs local control of filter processing on, for example, video data received via the tuner or the communication unit 1235 and video data recorded on the hard disk of the recording / playback unit 1233. be able to.

  The hard disk recorder 1200 uses the image encoding device 100 as the encoder 1251. Therefore, the encoder 1251 can suppress a reduction in the effect due to local control of the filter processing, as in the case of the image encoding device 100.

  Therefore, the hard disk recorder 1200 can more appropriately perform local control of filter processing for encoded data to be recorded on the hard disk, for example.

  In the above description, the hard disk recorder 1200 for recording video data and audio data on the hard disk has been described. Of course, any recording medium may be used. For example, even in a recorder to which a recording medium other than a hard disk such as a flash memory, an optical disk, or a video tape is applied, the image encoding device 100 and the image decoding device 200 are applied as in the case of the hard disk recorder 1200 described above. Can do.

<10. Tenth Embodiment>
[camera]
FIG. 33 is a block diagram illustrating a main configuration example of a camera using an image encoding device and an image decoding device to which the present invention has been applied.

  The camera 1300 shown in FIG. 33 images a subject and displays an image of the subject on the LCD 1316 or records it on the recording medium 1333 as image data.

  The lens block 1311 causes light (that is, an image of the subject) to enter the CCD / CMOS 1312. The CCD / CMOS 1312 is an image sensor using CCD or CMOS, converts the intensity of received light into an electric signal, and supplies it to the camera signal processing unit 1313.

  The camera signal processing unit 1313 converts the electrical signal supplied from the CCD / CMOS 1312 into Y, Cr, and Cb color difference signals, and supplies them to the image signal processing unit 1314. The image signal processing unit 1314 performs predetermined image processing on the image signal supplied from the camera signal processing unit 1313 or encodes the image signal with the encoder 1341 under the control of the controller 1321. The image signal processing unit 1314 supplies encoded data generated by encoding the image signal to the decoder 1315. Further, the image signal processing unit 1314 acquires display data generated in the on-screen display (OSD) 1320 and supplies it to the decoder 1315.

  In the above processing, the camera signal processing unit 1313 appropriately uses a DRAM (Dynamic Random Access Memory) 1318 connected via the bus 1317, and image data or a code obtained by encoding the image data as necessary. The digitized data or the like is held in the DRAM 1318.

  The decoder 1315 decodes the encoded data supplied from the image signal processing unit 1314 and supplies the obtained image data (decoded image data) to the LCD 1316. In addition, the decoder 1315 supplies the display data supplied from the image signal processing unit 1314 to the LCD 1316. The LCD 1316 appropriately synthesizes the image of the decoded image data supplied from the decoder 1315 and the image of the display data, and displays the synthesized image.

  Under the control of the controller 1321, the on-screen display 1320 outputs display data such as menu screens and icons composed of symbols, characters, or graphics to the image signal processing unit 1314 via the bus 1317.

  The controller 1321 executes various processes based on a signal indicating the content instructed by the user using the operation unit 1322, and also via the bus 1317, an image signal processing unit 1314, a DRAM 1318, an external interface 1319, an on-screen display. 1320, media drive 1323, and the like are controlled. The FLASH ROM 1324 stores programs and data necessary for the controller 1321 to execute various processes.

  For example, the controller 1321 can encode the image data stored in the DRAM 1318 or decode the encoded data stored in the DRAM 1318 instead of the image signal processing unit 1314 or the decoder 1315. At this time, the controller 1321 may be configured to perform encoding / decoding processing by a method similar to the encoding / decoding method of the image signal processing unit 1314 or the decoder 1315, or the image signal processing unit 1314 or the decoder 1315 is compatible. The encoding / decoding process may be performed by a method that is not performed.

  For example, when the start of image printing is instructed from the operation unit 1322, the controller 1321 reads out image data from the DRAM 1318 and supplies it to the printer 1334 connected to the external interface 1319 via the bus 1317. Let it print.

  Further, for example, when image recording is instructed from the operation unit 1322, the controller 1321 reads the encoded data from the DRAM 1318 and supplies it to the recording medium 1333 mounted on the media drive 1323 via the bus 1317. Remember.

  The recording medium 1333 is an arbitrary readable / writable removable medium such as a magnetic disk, a magneto-optical disk, an optical disk, or a semiconductor memory. Of course, the recording medium 1333 may be of any kind as a removable medium, and may be a tape device, a disk, or a memory card. Of course, a non-contact IC card or the like may be used.

  Further, the media drive 1323 and the recording medium 1333 may be integrated and configured by a non-portable storage medium such as a built-in hard disk drive or SSD (Solid State Drive).

  The external interface 1319 is composed of, for example, a USB input / output terminal, and is connected to the printer 1334 when printing an image. In addition, a drive 1331 is connected to the external interface 1319 as necessary, and a removable medium 1332 such as a magnetic disk, an optical disk, or a magneto-optical disk is appropriately mounted, and a computer program read from them is loaded as necessary. Installed in the FLASH ROM 1324.

  Furthermore, the external interface 1319 has a network interface connected to a predetermined network such as a LAN or the Internet. For example, the controller 1321 can read the encoded data from the DRAM 1318 in accordance with an instruction from the operation unit 1322 and supply the encoded data to the other device connected via the network from the external interface 1319. In addition, the controller 1321 acquires encoded data and image data supplied from another device via the network via the external interface 1319, holds the data in the DRAM 1318, or supplies it to the image signal processing unit 1314. Can be.

  The camera 1300 as described above uses the image decoding device 200 as the decoder 1315. Therefore, the decoder 1315 moves the position of the ALF block based on the offset value so as to align the boundary of the ALF block with the end of the slice, as in the case of the image decoding device 200. Thereby, the decoder 1315 can perform local control of the filter processing more appropriately.

  Therefore, for example, the camera 1300 performs a filtering process on image data generated in the CCD / CMOS 1312, encoded data of video data read from the DRAM 1318 or the recording medium 1333, and encoded data of video data acquired via the network. It is possible to more appropriately perform local control.

  The camera 1300 uses the image encoding device 100 as the encoder 1341. Therefore, the encoder 1341 can more appropriately perform local control of the filter processing, as in the case of the image encoding device 100.

  Therefore, for example, the camera 1300 can more appropriately perform local control of filter processing on encoded data recorded in the DRAM 1318 or the recording medium 1333 or encoded data provided to another device.

  Note that the decoding method of the image decoding device 200 or the image decoding device 400 may be applied to the decoding process performed by the controller 1321. Similarly, the encoding method of the image encoding device 100 may be applied to the encoding process performed by the controller 1321.

  The image data captured by the camera 1300 may be a moving image or a still image.

  Of course, the image encoding device 100 and the image decoding device 200 can also be applied to devices and systems other than the devices described above.

  The size of the macroblock is not limited to 16 × 16 pixels. For example, the present invention can be applied to macroblocks of any size such as 32 × 32 pixels shown in FIG.

  In the above description, the flag information or the like is described as being multiplexed (description) into the bitstream, but in addition to multiplexing, for example, a flag and image data (or bitstream) may be transmitted (recorded). Good. There may be a form in which the flag and the image data (or bit stream) are connected (added).

  Concatenation (addition) indicates a state in which image data (or bit stream) and a flag are linked to each other (a state in which correspondence is established), and the physical positional relationship is arbitrary. For example, the image data (or bit stream) and the flag may be transmitted through different transmission paths. Further, the image data (or bit stream) and the flag may be recorded on different recording media (or different recording areas in the same recording medium). Note that the unit for linking the image data (or bit stream) and the flag is arbitrary, and may be set, for example, in encoding processing units (one frame, multiple frames, etc.).

  DESCRIPTION OF SYMBOLS 100 Image coding apparatus, 112 Control information generation part, 113 Adaptive filter process part, 132 Block information generation part, 141 Process target slice area | region identification part, 142 ALF block setting part, 143 Offset process part, 144 Process target ALF block area | region identification Unit, 145 determination unit, 146 filter block flag generation unit, 171 control unit, 172 adaptive filter, 173 selection unit, 200 image decoding device, 202 lossless decoding unit, 207 adaptive filter processing unit, 431 setting unit, 432 generation unit, 433 Calculation unit, 434 determination unit

Claims (24)

When performing the adaptive filter processing on the slice to be processed and the slice control data for controlling the adaptive filter processing on the slice to be processed of the image data, for each pixel block having a quadtree structure included in the slice to be processed A generating unit that generates block control data for controlling whether to perform the adaptive filter processing;
The slice control data generated by the generating unit, or by using the slice control data and the block control data, a coding unit for generating an encoded stream,
An image encoding device comprising: a transmission unit that transmits the encoded stream generated by the encoding unit. It is determined whether the block is included in the processing target slice based on the position of the block obtained according to the block size of the block on which the adaptive filter processing is performed, and the block is included in the processing target slice. A determination unit that determines to perform the adaptive filter processing on the processing target slice,
The generation unit generates the slice control data or the slice control data and the block control data according to a determination result of the determination unit.
The image encoding device according to claim 1. The encoding unit includes the slice control data or the slice control data and the block control data generated by the generation unit in the encoded stream as a predetermined syntax.
The image encoding device according to claim 1. The encoding unit includes the slice control data in a slice header of the encoded stream
The image encoding device according to claim 3. An adaptive filter unit that performs the adaptive filter process on the image data according to the slice control data and the block control data generated by the generation unit is further provided.
The image encoding device according to claim 1. The image processing apparatus further includes a display control unit that displays the image subjected to the adaptive filter processing by the adaptive filter unit on a display
The image encoding device according to claim 5. A modulation unit that performs spread spectrum processing on the encoded stream generated by the encoding unit;
The transmission unit transmits the encoded stream that has been subjected to spread spectrum processing by the modulation unit.
The image encoding device according to claim 1. And a power supply unit that is activated by supplying power from the battery pack to each processing unit when the end call and the power key are turned on by a user operation.
The image encoding device according to claim 1. A signal processing unit that converts an image signal obtained by imaging the subject into image data of Y, Cr, and Cb;
The generation unit generates the slice control data and the block control data for Y, Cr, and Cb image data generated by the signal processing unit.
The image encoding device according to claim 1. The image processing apparatus further includes a storage unit that stores Y, Cr, and Cb image data generated by the signal processing unit or an encoded stream generated by the encoding unit.
The image encoding device according to claim 9. The transmission unit transmits the encoded data read from the storage unit
The image encoding device according to claim 10. When generating slice control data for controlling adaptive filter processing to a slice to be processed of image data, and performing the adaptive filter processing on the slice to be processed, further, a quad tree structure included in the slice to be processed Generating block control data for controlling whether to perform the adaptive filter processing for each pixel block;
Using the generated slice control data, or the slice control data and the block control data, generate an encoded stream,
Transmit the generated encoded stream
Image coding method. It is determined whether the block is included in the processing target slice based on the position of the block obtained according to the block size of the block on which the adaptive filter processing is performed, and the block is included in the processing target slice. If it is determined that the adaptive filter processing is performed on the processing target slice,
According to the determination result, the slice control data, or the slice control data and the block control data are generated.
The image encoding method according to claim 12. The generated slice control data, or the slice control data and the block control data are included in the encoded stream as a predetermined syntax.
The image encoding method according to claim 12. The slice control data is included in the slice header of the encoded stream
The image encoding method according to claim 14. The adaptive filter processing is performed on the image data according to the generated slice control data and the block control data.
The image encoding method according to claim 12. Displaying the adaptive filtered image on a display
The image encoding method according to claim 16. The generated encoded stream is subjected to spread spectrum processing,
Transmit the encoded stream that has undergone the spread spectrum processing
The image encoding method according to claim 12. When the end call and the power key are turned on by the user's operation, power is supplied to each processing unit from the battery pack to start the operation.
The image encoding method according to claim 12. An image signal obtained by imaging a subject is converted into Y, Cr, Cb image data,
The slice control data and the block control data are generated for the generated Y, Cr, and Cb image data.
The image encoding method according to claim 12. The generated Y, Cr, Cb image data or the generated encoded stream is stored in the storage unit.
The image encoding method according to claim 20. Transmit the encoded data read from the storage unit
The image encoding method according to claim 21. Computer
When performing the adaptive filter processing on the slice to be processed and the slice control data for controlling the adaptive filter processing on the slice to be processed of the image data, for each pixel block having a quadtree structure included in the slice to be processed A generating unit that generates block control data for controlling whether to perform the adaptive filter processing;
An encoding unit that generates an encoded stream using the slice control data generated by the generation unit, or the slice control data and the block control data;
A transmission unit for transmitting the encoded stream generated by the encoding unit;
A computer-readable recording medium on which a program that functions as a computer is recorded. Computer
When performing the adaptive filter processing on the slice to be processed and the slice control data for controlling the adaptive filter processing on the slice to be processed of the image data, for each pixel block having a quadtree structure included in the slice to be processed A generating unit that generates block control data for controlling whether to perform the adaptive filter processing;
An encoding unit that generates an encoded stream using the slice control data generated by the generation unit, or the slice control data and the block control data;
A transmission unit for transmitting the encoded stream generated by the encoding unit;
Program to make it work.

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