WO2013145174A1

WO2013145174A1 - Video encoding method, video decoding method, video encoding device, and video decoding device

Info

Publication number: WO2013145174A1
Application number: PCT/JP2012/058209
Authority: WO
Inventors: 隆志渡辺; 孝幸伊東; 山影　朋夫; 昭行谷沢
Original assignee: 株式会社東芝
Priority date: 2012-03-28
Filing date: 2012-03-28
Publication date: 2013-10-03

Abstract

According to an embodiment, a video encoding method includes encoding first filter coefficient information indicating a filter coefficient for each of one or more filters included in a first filter set specified for a decoded image. The video encoding method includes encoding filter switching information indicating whether to apply the first filter set or a second filter set specified for a pixel block to be processed in the decoded image when a loop filter process is applied to the pixel block to be processed, after the first filter coefficient information is encoded. The video encoding method includes encoding second filter coefficient information indicating a filter coefficient for each of one or more filters included in the second filter set when the second filter set is applied to the pixel block to be processed, after the first filter coefficient information is encoded.

Description

Moving picture coding method, moving picture decoding method, moving picture coding apparatus, and moving picture decoding apparatus

Embodiments relate to a moving image encoding technique and a decoding technique.

2. Description of the Related Art There is known a moving picture coding apparatus capable of setting a filter in units of LCU (Large Coding Unit) in a picture. This moving image encoding apparatus is also called an LCU base encoder. Here, LCU means a pixel block treated as a coding unit. Filter information corresponding to each LCU is encoded and signaled to the video decoding device. Regarding encoding of filter information corresponding to each LCU, for example, an encoding mode for newly encoding the filter information itself, an encoding mode for encoding information referring to the already encoded filter information, and the like are prepared. Is done. On the other hand, a picture-based encoder that sets a filter in units of pictures is also known.

Since the LCU base encoder can encode the filter information in units of LCUs, the delay associated with the encoding process can be reduced. On the other hand, according to the LCU base encoder, filters are optimized in units of LCUs, so it is necessary to set a large number of filters in a picture. Therefore, the overhead of encoded data tends to increase.

The picture-based encoder optimizes the filter for each picture. Therefore, according to the picture-based encoder, the total number of filters to be set is easily reduced as compared with the LCU-based encoder, and the overhead of encoded data is likely to be smaller than that of the LCU-based encoder. On the other hand, the picture-based encoder cannot set a filter until the encoding process for all the LCUs in the picture is completed. Therefore, the delay accompanying the encoding process is larger than that of the LCU-based encoder.

The embodiment is intended to reduce the overhead of encoded data. In addition, one of the purposes of the embodiment is to reduce the delay associated with the encoding process.

According to the embodiment, the moving image encoding method encodes first filter coefficient information indicating each filter coefficient of one or more filters included in a first filter set set for a decoded image. Including that. The moving image encoding method includes a first filter set and a second filter set set for the pixel block to be processed when loop filter processing is applied to the pixel block to be processed in the decoded image. It includes encoding the filter switching information indicating which is applied after the first filter coefficient information is encoded. When the second filter set is applied to the pixel block to be processed, the moving image encoding method uses the second filter coefficient indicating each filter coefficient of one or more filters included in the second filter set. Encoding the information after the first filter coefficient information is encoded. The moving image encoding method generates a pixel block in a reference image by applying one of the first filter set and the second filter set to the pixel block to be processed based on the filter switching information. Including that.

1 is a block diagram illustrating a moving image encoding apparatus according to a first embodiment. The block diagram which illustrates the loop filter information generation part of FIG. FIG. 2 is a block diagram illustrating a loop filter processing unit in FIG. 1. Explanatory drawing of the syntax structure of a picture base encoder. Explanatory drawing of the syntax structure of a LCU base encoder. Explanatory drawing of the syntax structure which the moving image encoding device and moving image decoding device which concern on 1st Embodiment use. The figure which illustrates the syntax which the moving image encoder which concerns on 1st Embodiment uses in order to encode 1st filter coefficient information. The figure which illustrates the syntax which the moving image encoder which concerns on 1st Embodiment uses in order to encode filter switching information and 2nd filter coefficient information. The figure which illustrates the syntax which the moving image encoder which concerns on 1st Embodiment uses in order to encode filter switching information and 2nd filter coefficient information. The figure which illustrates the syntax which the moving image encoder which concerns on 1st Embodiment uses in order to encode filter switching information and 2nd filter coefficient information. The figure which illustrates the syntax which the moving image encoder which concerns on 1st Embodiment uses in order to encode filter switching information and 2nd filter coefficient information. 6 is a flowchart illustrating a part of an encoding process performed by the moving image encoding apparatus according to the first embodiment. 1 is a block diagram illustrating a moving image decoding apparatus according to a first embodiment. The block diagram which illustrates the moving picture coding device concerning a 2nd embodiment. The block diagram which illustrates the moving picture decoding device concerning a 2nd embodiment. The block diagram which illustrates the animation coding device concerning a 3rd embodiment. The block diagram which illustrates the video decoding device concerning a 3rd embodiment. The block diagram which illustrates the video decoding device concerning a 4th embodiment. FIG. 10 is a block diagram illustrating a moving image encoding apparatus according to a fifth embodiment. The block diagram which illustrates the moving picture decoding device concerning a 5th embodiment.

Hereinafter, embodiments will be described with reference to the drawings. Hereinafter, the same or similar elements as those already described are denoted by the same or similar reference numerals, and redundant description is basically omitted.

In the following description, the filter process may be a process of multiply-adding the pixel values of the pixel to be processed and one or more peripheral pixels using a plurality of filter coefficients, but is not limited thereto. For example, the filtering process may be only a process of adding one filter coefficient (also called an offset value) to the pixel value of the pixel to be processed. Alternatively, the filtering process may be a process of adding a single filter coefficient (also referred to as an offset value) after performing a product-sum operation on pixel values of the processing target pixel and one or more neighboring pixels using a plurality of filter coefficients. Good.

(First embodiment)
(Moving picture encoding device)
As illustrated in FIG. 1, the moving picture coding apparatus according to the first embodiment includes a moving picture coding unit 1000 and a coding control unit 111. The moving image encoding unit 1000 includes a predicted image generation unit 101, a subtraction unit 102, a transform / quantization unit 103, an entropy encoding unit 104, an inverse quantization / inverse transform unit 105, an addition unit 106, A loop filter information generation unit 107, a loop filter processing unit 108, a first filter setting unit 109, and a first filter buffer 110 are provided. The encoding control unit 111 controls the operation of each unit of the moving image encoding unit 1000.

The predicted image generation unit 101 generates the predicted image 11 by performing the prediction process of the input image 10 in units of pixel blocks, for example. The input image 10 includes a plurality of pixel signals and is acquired from the outside of the moving image encoding device. The prediction process may be a general process such as a temporal inter-screen prediction process using motion compensation and a spatial intra-screen prediction process using encoded pixels in the screen. For example, the predicted image generation unit 101 may perform a prediction process on the input image 10 based on a loop filter processed image 19 described later. The predicted image generation unit 101 outputs the predicted image 11 to the subtraction unit 102 and the addition unit 106.

The subtraction unit 102 acquires the input image 10 from the outside of the moving image encoding device, and inputs the predicted image 11 from the predicted image generation unit 101. The subtraction unit 102 subtracts the prediction image 11 from the input image 10 to generate a prediction error image 12. The subtraction unit 102 outputs the prediction error image 12 to the transform / quantization unit 103.

The transform / quantization unit 103 receives the prediction error image 12 from the subtraction unit 102. The transform / quantization unit 103 performs transform processing on the prediction error image 12 to generate transform coefficients. Further, the transform / quantization unit 103 quantizes the transform coefficient to generate a quantized transform coefficient. The transform / quantization unit 103 outputs the quantized transform coefficient to the entropy coding unit 104 and the inverse quantization / inverse transform unit 105. Here, the transformation process is typically orthogonal transformation such as Discrete Cosine Transform (DCT). Note that the conversion process is not limited to DCT, and may be, for example, wavelet conversion, independent component analysis, or the like. The quantization process is performed based on the quantization parameter set by the encoding control unit 111.

The entropy encoding unit 104 receives the quantized transform coefficient from the transform / quantization unit 103, receives the filter switching information 14 and the second filter coefficient information 15 from the loop filter information generation unit 107, and receives from the first filter buffer 110. The first filter coefficient information 13 is input, and the encoding parameter is input from the encoding control unit 111. The encoding parameters may include, for example, prediction mode information, motion information, encoded block division information, quantization parameters, and the like.

The entropy coding unit 104 performs entropy coding (for example, Huffman coding, arithmetic coding) on the quantized transform coefficient, the first filter coefficient information 13, the filter switching information 14, the second filter coefficient information 15, and the coding parameter according to the syntax. Encoded data 17 is generated. Details of the syntax used by the entropy encoding unit 104 will be described later. The entropy encoding unit 104 outputs the encoded data 17 to the outside of the moving image encoding apparatus (for example, a communication system, a storage system, etc.). The encoded data 17 is decoded by a moving picture decoding apparatus described later.

The inverse quantization / inverse transform unit 105 inputs the quantized transform coefficient from the transform / quantization unit 103. The inverse quantization / inverse transform unit 105 generates transform coefficients by inverse quantization of the quantized transform coefficients. Further, the inverse quantization / inverse transform unit 105 generates a prediction error image by performing an inverse transform process on the transform coefficient. The inverse quantization / inverse transform unit 105 outputs the prediction error image to the addition unit 106. Basically, the inverse quantization / inverse transform unit 105 performs the inverse process of the transform / quantization unit 103. That is, the inverse quantization is performed based on the quantization parameter set by the encoding control unit 111. Further, the inverse transform process is determined by the transform process performed by the transform / quantization unit 103. The inverse transform process is, for example, inverse DCT (Inverse DCT; IDCT), inverse wavelet transform, or the like.

The addition unit 106 receives the prediction image 11 from the prediction image generation unit 101 and inputs the prediction error image from the inverse quantization / inverse conversion unit 105. The adding unit 106 adds the prediction error image to the prediction image to generate a (local) decoded image 16. Adder 106 outputs decoded image 16 to loop filter information generator 107 and loop filter processor 108.

Here, the loop filter information generation unit 107 and the loop filter processing unit 108 perform processing in units of pixel blocks. The pixel block is typically handled as a coding unit. The pixel block is, for example, H.264. It corresponds to a macroblock in H.264 / AVC, an LCU in HEVC (High Efficiency Video Coding), and the like. In the following description, for convenience, it is assumed that the pixel block corresponds to an LCU. However, the present embodiment is applicable even when the pixel block does not correspond to an LCU.

The loop filter information generation unit 107 acquires the input image 10 in units of pixel blocks from the outside of the video encoding device, inputs the decoded image 16 in units of pixel blocks from the addition unit 106, and receives the first image from the first filter buffer 110. The filter coefficient information 13 is input.

The loop filter information generation unit 107 generates filter setting information 18 corresponding to the pixel block to be processed based on the input image 10 and the decoded image 16. In addition, the loop filter information generation unit 107 generates second filter coefficient information 15 corresponding to the pixel block to be processed based on the filter setting information 18. Furthermore, the loop filter information generation unit 107 generates filter switching information 14 corresponding to the pixel block to be processed based on the input image 10, the first filter coefficient information 13, the second filter coefficient information 15, and the decoded image 16. .

Here, the first filter coefficient information 13 is information indicating each filter coefficient of one or more filters included in the first filter set set in units of pictures. The filter switching information 14 is information indicating which of the first filter set and the second filter set is applied when the loop filter process is applied to the corresponding pixel block. The second filter coefficient information 15 is information indicating each filter coefficient of one or more filters included in the second filter set set in pixel block units. The filter setting information 18 means information necessary for setting a filter coefficient for a pixel block to be processed.

The loop filter information generation unit 107 outputs the filter switching information 14 and the second filter coefficient information 15 to the entropy encoding unit 104 and the loop filter processing unit 108. The loop filter information generation unit 107 outputs the filter setting information 18 to the first filter setting unit 109.

Specifically, as illustrated in FIG. 2, the loop filter information generation unit 107 includes a filter setting information generation unit 112, a second filter setting unit 113, and a filter switching information generation unit 114.

The filter setting information generation unit 112 acquires the input image 10 from the outside of the video encoding device in units of pixel blocks, and inputs the decoded image 16 from the addition unit 106 in units of pixel blocks. The filter setting information generation unit 112 generates filter setting information 18 corresponding to the pixel block to be processed based on the input image 10 and the decoded image 16. The filter setting information generation unit 112 outputs the filter setting information 18 to the first filter setting unit 109 and the second filter setting unit 113.

For example, when the loop filter processing unit 108 performs, for example, a two-dimensional Wiener filter process, the filter information generation unit 112 sets a filter indicating a correlation matrix based on the input image 10 in units of pixel blocks and the decoded image 16 in units of pixel blocks. Information 18 is generated. The Wiener filter is a so-called pixel restoration filter and can minimize the residual sum of squares between the input image 10 and the loop filter processed image 19.

The second filter setting unit 113 receives the filter setting information 18 from the filter setting information generation unit 112. The second filter setting unit 112 sets the filter coefficient of each of the one or more filters included in the second filter set applicable to the pixel block to be processed based on the filter setting information 18, thereby Two filter coefficient information 15 is generated. The second filter setting unit 113 outputs the second filter coefficient information 15 to the entropy encoding unit 104, the loop filter processing unit 108, and the filter switching information generation unit 114.

For example, when the loop filter processing unit 108 performs, for example, a two-dimensional Wiener filter process, the second filter setting unit 113 regards the correlation matrix indicated by the filter setting information 18 as simultaneous equations and solves the simultaneous equations, Second filter coefficient information 15 can be generated.

The filter switching information generation unit 114 acquires the input image 10 from the outside of the video encoding device in units of pixel blocks, inputs the decoded image 16 from the addition unit 106 in units of pixel blocks, and receives the first image from the first filter buffer 110. The filter coefficient information 13 is input, and the second filter coefficient information 15 is input from the second filter setting unit 113.

The filter switching information generation unit 114 determines which of the first filter set and the second filter set is applied to the pixel block to be processed based on the input image 10 and the decoded image 16. The filter switching information generation unit 114 can use, for example, the encoding cost represented by the following mathematical formula (1) in order to determine the filter set to be applied, but is not limited to this, and any technique can be used. The filter switching information generation unit 114 generates filter switching information 14 based on the determination result. The filter switching information generation unit 114 outputs the filter switching information 14 to the entropy encoding unit 104 and the loop filter processing unit 108.

In Equation (1), Cost represents coding cost, D represents residual sum of squares, λ represents a coefficient, and R represents a code amount. When the loop filter processing unit 108 performs, for example, two-dimensional Wien filter processing, by applying a filter set to the pixel block to be processed, the input image 10 and the loop filter in the pixel block as described above. The residual sum of squares with the processed image 19 can be minimized. Therefore, the residual sum of squares when the second filter set is applied does not become larger than the residual sum of squares when the first filter set is applied if the influence of the filter coefficient calculation accuracy is sufficiently small. On the other hand, since the first filter coefficient information 13 is encoded in units of pictures, when the first filter set is applied to a pixel block, information indicating the filter coefficient itself is newly encoded for the pixel block. do not have to. Therefore, in general, the code amount when the first filter set is applied is not larger than the code amount when the second filter set is applied. That is, according to the above formula (1), the trade-off between the residual sum of squares and the code amount can be taken into account in the determination of the filter set applied to the pixel block.

The filter switching information 14 is obtained by applying a loop filter process to the corresponding pixel block in addition to information indicating which of the first filter set and the second filter set is applied to the corresponding pixel block. It may further include information indicating whether or not. That is, the filter switching information 14 includes information indicating whether or not the loop filter processing is applied to the corresponding pixel block, and the first filter set and the second filter set when the loop filter processing is applied. Information indicating which is applied.

Generally, since the first filter set is set in units of pictures, there is a risk that the residual sum of squares may be increased for some pixel blocks in the picture. In such a case, the residual sum of squares when the loop filter process is not applied is smaller than the residual sum of squares when the first filter set is applied. Further, when the loop filter process is not applied, it is not necessary to encode the filter coefficient information, so that the code amount does not increase compared to the case where the first filter set or the second filter set is applied. Therefore, the encoding cost when the loop filter processing is not applied may be smaller than the encoding cost when the first filter set is applied and the encoding cost when the second filter set is applied. is there. In such a case, the filter switching information generation unit 114 may generate filter switching information 14 indicating that the loop filter process is not applied to the pixel block.

The loop filter processing unit 108 inputs the decoded image 16 from the addition unit 106 in units of pixel blocks, receives the filter switching information 14 and the second filter coefficient information 15 from the loop filter information generation unit 107, and receives from the first filter buffer 110. First filter coefficient information 13 is input.

The loop filter processing unit 108 applies either one of the first filter set and the second filter set based on the filter switching information 14 corresponding to the pixel block to be processed. Specifically, the loop filter processing unit 108 performs a loop filter process on the pixel block to be processed using the first filter coefficient information 13 or the second filter coefficient information 15, so that the pixels in the loop filter processed image 19 are processed. Generate a block. As described above, if the filter switching information 14 indicates that the loop filter process is not applied to the pixel block to be processed, the loop filter processing unit 108 omits the loop filter process for the pixel block to be processed.

The loop filter processed image 19 may be stored in a storage unit (not shown) (for example, a buffer) accessible by the predicted image generation unit 101. The loop filter processed image 19 is read as a reference image by the predicted image generation unit 101 as necessary, and is used for the prediction process.

Specifically, as illustrated in FIG. 3, the loop filter processing unit 108 includes a switch 115 and a filter application unit 116.

The switch 115 receives the first filter coefficient information 13 from the first filter buffer 110, and receives the filter switching information 14 and the second filter coefficient information 15 corresponding to the pixel block to be processed from the loop filter information generation unit 108. The switch 115 selects one of the first filter coefficient information 13 and the second filter coefficient information 15 based on the filter switching information 14, and selects the selected filter coefficient information (hereinafter referred to as selected filter coefficient information). ) To the filter application unit 116. That is, if the filter switching information 14 indicates that the first filter set is applied to the pixel block to be processed, the switch 115 selects the first filter coefficient information 13. On the other hand, if the filter switching information 14 indicates that the second filter set is applied to the pixel block to be processed, the switch 115 selects the second filter coefficient information 15. If the filter switching information 14 indicates that the loop filter processing is not applied to the pixel block to be processed, the switch 115 selects neither the first filter coefficient information 13 nor the second filter coefficient information 15.

The filter application unit 116 inputs the decoded image 16 from the addition unit 106 in units of pixel blocks, and inputs selection filter coefficient information from the switch 115. The filter application unit 116 generates a pixel block in the loop filter processed image 19 by performing filter processing on the pixel block to be processed based on the selected filter coefficient information. The filter application unit 116 outputs the loop filter processed image 19 to the predicted image generation unit 101. If the filter switching information 14 indicates that the loop filter process is not applied to the pixel block to be processed as described above, the filter application unit 116 directly uses the pixel block in the loop filter processed image 19 as it is. Use as

The first filter setting unit 109 receives the filter setting information 18 from the loop filter information setting unit 107. The first filter setting unit 109 collects filter setting information 18 corresponding to, for example, all pixel blocks in a picture, and sets filter coefficients of the first filter set for subsequent pictures based on the collected filter setting information 18. Set. The first filter setting unit 109 stores filter coefficient information indicating the set filter coefficient in the first filter buffer 110. The subsequent picture may be a picture immediately after the picture to be processed in the encoding order, or may be a picture that is two or more pictures after.

For example, when the loop filter processing unit 108 performs a two-dimensional Wine filter process, the first filter setting unit 109 collects filter setting information 18 corresponding to all or some of the pixel blocks in the picture. Then, the first filter setting unit 109 integrates the correlation matrix by calculating the element sum of the correlation matrix indicated by the collected filter setting information 18. The loop filter information 108 can set filter coefficient information for subsequent pictures by regarding the integrated correlation matrix as simultaneous equations and solving the simultaneous equations.

However, the first filter setting unit 109 does not necessarily need to set the filter coefficient information for the subsequent picture based on the filter setting information 18 of the pixel block in the current picture. For example, the first filter setting unit 109 may be able to refer to default filter coefficient information. Then, the first filter setting unit 109 may store default filter coefficient information in the first filter buffer 110 without depending on the filter setting information 18.

The filter coefficient information stored in the first filter buffer 110 is converted into first filter coefficient information 13 by the entropy encoding unit 104, the loop filter information generation unit 107, and the loop filter processing unit 108 in the encoding process for subsequent pictures. Read out. The first filter buffer 110 may store filter coefficient information for a plurality of filter sets at the same time. In such a case, the first filter coefficient information 13 of the current picture corresponds to, for example, the level of the quantization parameter set for the picture from the filter coefficient information of the plurality of filter sets stored in the first filter buffer. May be selected.

In short, the first filter coefficient information 13 is typically set based on the filter setting information 18 of the LCU in the preceding picture. Thus, the first filter set does not necessarily minimize the residual sum of squares for the entire current picture. However, generally, since the correlation of image characteristics between pictures is high, the first filter coefficient information 13 set based on the filter setting information 18 of the LCU in the preceding picture is generally a residual even for the current picture. Suboptimal filtering that reduces the sum of squares can be realized.

The encoding control unit 111 performs encoding block division control, generated code amount feedback control, quantization control, mode control, and the like for the moving image encoding unit 1000. The encoding control unit 111 outputs the encoding parameter to the entropy encoding unit 104.

Hereinafter, the syntax used by the entropy encoding unit 104 will be described. In the following description, a syntax structure including a sequence level syntax, a picture level syntax, a slice level syntax, and an LCU level syntax is assumed.

For example, the upper layer syntax information relating to the entire moving image such as the vertical and horizontal sizes of the image is encoded in the sequence level syntax SPS (Sequence Parameter Set). Syntax information necessary for decoding at the picture level is encoded in PPS (Picture Parameter Set) or APS (Adaptation Parameter Set) of picture level syntax. Syntax information necessary for decoding at the slice level is encoded in the slice header of the slice level syntax. In the LCU level syntax, for example, syntax information such as quantization transform coefficients and prediction mode information of each LCU is encoded.

FIG. 4 shows a syntax structure according to the first comparative example. The syntax structure of FIG. 4 is disclosed in WD5 (Working Draft 5) of HEVC. According to the syntax structure of FIG. 4, the filter coefficient information is set in units of pictures and is encoded in APS with picture level syntax. Also, filter application information indicating whether or not a filter is applied in each LCU is collectively encoded in a slice header of slice level syntax. That is, the syntax structure of FIG. 4 is used by a so-called picture-based encoder. According to the syntax structure of FIG. 4, filter coefficient information that minimizes the residual sum of squares can be set for each picture. On the other hand, since the filter coefficient information cannot be set until the encoding process of all the LCUs is completed, the delay until the encoded data is output is large.

FIG. 5 shows a syntax structure according to the second comparative example. The syntax structure of FIG. 5 is disclosed in Non-Patent Document 2. According to the syntax structure of FIG. 5, the filter coefficient information is set for each LCU, and is encoded for each LCU in the LCU level syntax. However, when the filter is not applied to the LCU and when referring to already encoded filter coefficient information in the same slice, the encoding of the filter coefficient information can be omitted. Further, it indicates whether or not a filter is applied in each LCU. Further, when a filter is applied, filter application information indicating whether the filter is an encoded filter or a new filter in the same slice. In the LCU level syntax, each LCU is encoded. That is, the syntax structure of FIG. 5 is used by a so-called LCU-based encoder. According to the syntax structure of FIG. 5, it is possible to set filter coefficient information that minimizes the residual sum of squares in units of LCUs. Furthermore, since encoded data can be sequentially output every time encoding processing in units of LCU is completed, delay can be reduced. On the other hand, since the filters are optimized on an LCU basis, the set filters are diversified, and the overhead of filter coefficient information is likely to increase.

The entropy encoding unit 104 uses, for example, the syntax structure shown in FIG. According to the syntax structure of FIG. 6, the first filter coefficient information 13 is set for each picture and is encoded in the APS of the picture level syntax. The filter switching information 14 is set for each LCU, and is encoded for each LCU in the LCU level syntax. The second filter coefficient information 15 is also set for each LCU, and is encoded for each LCU in the LCU level syntax. However, when at least the second filter set is not applied to the LCU, the encoding of the second filter coefficient information 15 can be omitted.

As described above, the first filter coefficient information 13 is set for the following picture by the first filter setting unit 109. In other words, the first filter coefficient information 13 is stored in the first filter buffer 110 before the encoding process for the first LCU of each picture starts. Therefore, according to the syntax structure of FIG. 6, the encoded data 17 can be sequentially output every time the encoding process in units of LCU is completed as in the LCU base encoder, so that the delay can be reduced.

Further, according to the syntax structure of FIG. 6, the first filter set may be applied instead of the second filter set based on, for example, the above-described tradeoff between the residual sum of squares and the code amount. Therefore, since the total number of second filter sets to be set is reduced as compared with the LCU-based encoder, the overhead of the encoded data 17 can be reduced. Furthermore, as described above, if the sub-optimal first filter set is set based on the preceding picture, the possibility that the first filter set is applied to the LCU in the current picture increases. The overhead of the encoded data 17 is likely to be reduced.

The entropy encoding unit 104 can use, for example, the syntax shown in FIG. 7 to encode the first filter coefficient information 13. FIG. 7 illustrates information related to loop filter processing in the APS illustrated in FIG.

In FIG. 7, aps_id is identification information for specifying an APS that is referenced in a layer below the slice level. For example, by encoding aps_id in the slice header, the slice can refer to any one of the already encoded APSs.

In FIG. 6, the APS in which the first filter coefficient information 13 is encoded and the encoded data of the LCU that can refer to the first filter coefficient information 13 are depicted as being continuous. However, since the first filter coefficient information 13 that can be referred to by a given LCU is uniquely specified by using aps_id, the APS in which the first filter coefficient information 13 is encoded and the first filter coefficient information 13 are referred to. There is no need to continuously encode the encoded data of possible LCUs. In addition, if a plurality of APSs are encoded in units of pictures, the first filter coefficient information 13 that can be referred to can be adaptively switched in units of slices.

In FIG. 7, picture_based_filter_flag is information indicating whether or not the first filter coefficient information 13 is encoded in the current APS. If picture_based_filter_flag is 1, information on the first filter set including the first filter coefficient information 13 is encoded in the current APS.

Picture_based_filter_num_information is information indicating the total number of filters included in the first filter set. In FIG. 7, the total number of filters included in the first filter set is represented as PictureBasedFilterNum. As described above, the first filter set can include one or more filters. The picture_based_filter_num_information may be obtained by encoding the total number of filters included in the first filter set, or may be obtained by subtracting 1 from the total number of filters included in the first filter set. It may be converted into one. Alternatively, if the total number of filters included in the first filter set is determined in advance, encoding of picture_based_filter_num_information can be omitted. In any case, a design is required so that the video decoding device can derive the total number of filters included in the first filter set.

When the first filter set includes a plurality of filters, it is possible to switch the filter applied to each local region in the pixel block. This filter switching rule is encoded as picture_based_filter_group_information.

HEVC WD5 discloses rules for switching up to 16 filters. Specifically, the 4 × 4 pixel area is classified into a maximum of 16 classes based on the gradient direction and activity of the pixel values of the 4 × 4 pixel area. Each of these classes specifies the filter to be applied. A filter corresponding to the class is applied to each 4 × 4 pixel region. Further, by integrating two or more of these 16 classes, the total number of classes (ie, the total number of filters) can be arbitrarily reduced. Then, in the HEVC WD5, the class integration information is encoded as picture_based_filter_group_information.

Since switching of the filter can be realized based on various rules, various information may be encoded as picture_based_filter_group_information. Alternatively, if a filter switching rule is determined in advance, encoding of picture_based_filter_group_information can be omitted. In any case, a design is required that allows the video decoding device to switch between a plurality of filters included in the first filter set.

In FIG. 7, picture_based_filter_pred_information is information indicating a prediction method for encoding the first filter coefficient information 13. The filter coefficient indicated by the first filter coefficient information 13 may be encoded as it is, or a prediction residual obtained by performing a prediction process on the filter coefficient may be encoded instead. In general, if an appropriate prediction process is performed, the absolute value of the prediction residual is smaller than the absolute value of the filter coefficient, so that the generated code amount decreases.

Various prediction methods are disclosed in HEVC WD5. Specifically, a method for predicting each filter coefficient of the first filter included in the same filter set based on the filter coefficient at the same position of the second filter can be prepared. Further, it is possible to prepare a method for predicting other filter coefficients in the filter based on a part of the filter coefficients in the filter on the assumption that the gain of the filter (that is, the sum of the filter coefficients) is constant. .

Since the prediction of filter coefficients can be realized based on various methods, various information may be encoded as picture_based_filter_pred_information. Alternatively, if the prediction method of the filter coefficient is determined in advance, encoding of picture_based_filter_pred_information can be omitted. In any case, a design that allows the video decoding device to derive a filter coefficient prediction method is required.

In FIG. 7, picture_based_filter_coeff [i] [j] corresponds to the encoded first filter coefficient information 13. Specifically, information indicating the j-th filter coefficient of the i-th filter in the first filter set is encoded as picture_based_filter_coeff [i] [j]. Here, the filter coefficient means a prediction residual when the above-described filter coefficient prediction is performed, and otherwise means a filter coefficient value itself. In FIG. 7, PictureBasedFilterCoeffNum indicates the total number of filter coefficients included in each filter included in the first filter set.

The entropy encoding unit 104 can use, for example, the syntax shown in FIG. 8 to encode the filter switching information 14 and the second filter coefficient information 15. FIG. 8 illustrates information related to loop filter processing in the LCU level syntax shown in FIG.

In FIG. 8, lcu_based_filter_flag indicates whether or not loop filter processing (that is, the first filter set or the second filter set) is applied to the corresponding LCU. That is, lcu_based_filter_flag corresponds to a part of the filter switching information 14 encoded. If lcu_based_filter_flag is 1, information on loop filter processing applied to the corresponding LCU is further encoded.

In FIG. 8, new_filter_flag indicates which of the first filter set and the second filter set is applied to the corresponding LCU. That is, new_filter_flag corresponds to a part of the filter switching information 14 encoded. If new_filter_flag is 1, information on the second filter set applied to the corresponding LCU (including the second filter coefficient information 15) is further encoded. On the other hand, if new_filter_flag is 1, no further information needs to be encoded since the first filter set is applied to the corresponding LCU.

In FIG. 8, lcu_based_filter_num_information is information indicating the total number of filters included in the second filter set applied to the corresponding LCU. In FIG. 8, the total number of filters included in the second filter set is expressed as LCUBasedFilterNum.

When the total number of filters included in the second filter set is plural, it is possible to switch the filter applied to each local region in the pixel block. This filter switching rule is encoded as lcu_based_filter_group_information.

8, lcu_based_filter_pred_information is information indicating a prediction method for encoding the second filter coefficient information 15. In addition to the above prediction method, a method of predicting the second filter coefficient information 15 based on the first filter coefficient information 13 can also be used.

In FIG. 8, lcu_based_filter_coeff [i] [j] corresponds to the encoded second filter coefficient information 15 corresponding to the pixel block to be processed. Specifically, information indicating the j-th filter coefficient of the i-th filter in the second filter set is encoded as lcu_based_filter_coeff [i] [j]. Here, the filter coefficient means a prediction residual when the above-described filter coefficient prediction is performed, and otherwise means a filter coefficient value itself. In FIG. 8, LCUBasedFilterCoeffNum indicates the total number of filter coefficients included in each filter included in the second filter set.

Incidentally, as described above, the second filter set is set in units of LCUs. Therefore, the syntax information related to the second filter set has a larger influence on the overhead of the encoded data 17 than the syntax information related to the first filter set. Therefore, the overhead of the encoded data 17 can be effectively reduced by appropriately reducing the size of the syntax information related to the second filter set.

For example, if the total number of filters included in the second filter set is fixed to 1, it is not necessary to encode lcu_based_filter_num_information and lcu_based_filter_group_information. Furthermore, since the total number of filters is minimized, the total number of filter coefficients is also minimized.

Also, depending on the shape of the filter (for example, the number of taps), the total number of filter coefficients that the filter has increases or decreases. Therefore, the overhead of the encoded data 17 can be effectively reduced by appropriately setting the filter shape. For example, the shape of each filter included in the first filter set may not match the shape of each filter included in the second filter set. Specifically, since the first filter set is set in units of pictures, a large overhead is allowed as compared with the second filter set. That is, the total number of filter coefficients included in each filter included in the first filter set may be larger than the total number of filter coefficients included in each filter included in the second filter set. The shape of each filter may be changed according to a predetermined rule, and information indicating the shape of each filter may be signaled. At this time, for example, if the shape of the filter included in the second filter set is a subset of the shape of the filter included in the first filter set, the circuit scale for realizing the filter processing is reduced. You can also.

The entropy encoding unit 104 may use, for example, the syntax shown in FIG. 9 instead of FIG. 8 in order to encode the filter switching information 14 and the second filter coefficient information 15. FIG. 9 illustrates information related to loop filter processing in the LCU level syntax shown in FIG.

According to the syntax of FIG. 8, when the second filter set is applied to the LCU, the syntax information regarding the second filter set is encoded. However, the second filter set applied to the LCU may be the same as the second filter set applied to the already encoded LCU. Therefore, the syntax of FIG. 9 allows to refer to syntax information regarding the second filter set corresponding to the already encoded LCU in such a case. Therefore, according to the syntax of FIG. 9, it is possible to simplify the encoding of syntax information regarding the second filter set applied to the current LCU.

In the syntax of FIG. 9, lcu_based_filter_flag, lcu_based_filter_num_information, LCUBasedFilterNum, lcu_based_filter_group_information, lcu_based_filter_pred_information, the role of LCUBasedFilterCoeffNum and lcu_based_filter_coeff [i] [j] is identical or similar to that of FIG.

In the syntax of FIG. 9, new_filter_flag is information indicating whether or not the second filter set is applied to the corresponding LCU and syntax information related to the second filter set needs to be newly encoded. That is, new_filter_flag corresponds to a part of the filter switching information 14 encoded. If new_filter_flag is 1, information on the second filter set applied to the corresponding LCU (including the second filter coefficient information 15) is further encoded.

If new_filter_flag is 0, the first filter set or the same second filter set as the already encoded LCU is applied to the corresponding LCU. The filter set applied to the LCU is determined by the picture_based_filter_flag. That is, in the syntax of FIG. 9, picture_based_filter_flag corresponds to an encoded part of the filter switching information 14. If picture_based_filter_flag is 1, no further information needs to be encoded since the first filter set is applied to the corresponding LCU.

If new_filter_flag is 0 and picture_based_filter_flag is 0, the same second filter set as the already encoded LCU is applied to the corresponding LCU. In this case, the stored_filter_idx is encoded as identification information for referring to the syntax information related to the second filter set corresponding to the already encoded LCU, whereby the second filter set applied to the current LCU. It is possible to simplify the encoding of the syntax information regarding. Note that the syntax information referred to by stored_filter_idx is required to be common between the video encoding device and the video decoding device.

FIG. 10 shows a modification of the syntax of FIG. In the syntax of FIG. 10, lcu_based_filter_flag, lcu_based_filter_num_information, LCUBasedFilterNum, lcu_based_filter_group_information, lcu_based_filter_pred_information, the role of LCUBasedFilterCoeffNum and lcu_based_filter_coeff [i] [j] is identical or similar to that of FIG. Further, in the syntax of FIG. 10, the role of stored_filter_idx is the same as or similar to that of FIG.

In the syntax of FIG. 10, picture_based_filter_flag is information indicating whether the first filter set or the second filter set is applied to the corresponding LCU. That is, in the syntax of FIG. 10, picture_based_filter_flag corresponds to a part of the filter switching information 14 encoded. If picture_based_filter_flag is 1, no further information needs to be encoded since the first filter set is applied to the corresponding LCU. On the other hand, if picture_based_filter_flag is 0, new_filter_flag is further encoded.

New_filter_flag is information indicating whether or not it is necessary to newly encode syntax information related to the second filter set applied to the corresponding LCU. If new_filter_flag is 1, information on the second filter set applied to the corresponding LCU (including the second filter coefficient information 15) is further encoded. If new_filter_flag is 0, the same LCU as the already encoded LCU is applied to the corresponding LCU. Therefore, by encoding stored_filter_idx, encoding of syntax information regarding the second filter set applied to the corresponding LCU can be simplified.

According to the syntax of FIG. 10, it is not necessary to encode new_filter_flag when the first filter set is applied to the LCU. According to the syntax of FIG. 9, it is necessary to encode new_filter_flag even when the first filter set is applied to the LCU. Therefore, according to the syntax of FIG. 10, when there is a high possibility that the first filter set is applied to the LCU as compared to the syntax of FIG. 9 (for example, residual by applying the first filter set). The overhead of the encoded data 17 can be reduced when the square sum reduction effect is high for the entire picture.

On the other hand, according to the syntax of FIG. 10, it is necessary to encode picture_based_filter_flag even when the second filter set is applied to the LCU. According to the syntax of FIG. 9, when the second filter set is applied to the LCU and syntax information related to the second filter set needs to be newly encoded, it is not necessary to encode the picture_based_filter_flag. Therefore, according to the syntax of FIG. 9, there is a high possibility that the second filter set is applied to the LCU as compared to the syntax of FIG. 10 (for example, the residual by applying the first filter set). The overhead of the encoded data 17 can be reduced when the square sum reduction effect is low for the entire picture.

FIG. 11 also shows a modification of the syntax of FIG. In the syntax of FIG. 11, lcu_based_filter_flag, lcu_based_filter_num_information, LCUBasedFilterNum, lcu_based_filter_group_information, lcu_based_filter_pred_information, the role of LCUBasedFilterCoeffNum and lcu_based_filter_coeff [i] [j] is identical or similar to that of FIG. In the syntax of FIG. 11, new_filter_flag is the same as or similar to that of FIG.

In the syntax of FIG. 11, the picture_based_filter_flag encoded in the syntax of FIG. 9 and the syntax of FIG. 10 is not encoded. However, in the syntax of FIG. 11, any one value (for example, 0) of stored_filter_idx is used to refer to the syntax information regarding the first filter set. That is, in the syntax of FIG. 11, stored_filter_idx corresponds to a part of the filter switching information 14 encoded. For example, if new_filter_flag is 0 and stored_filter_idx is 0, the first filter set is applied to the corresponding LCU. On the other hand, if new_filter_flag is 0 and stored_filter_idx is not 0, the same second filter set as the already encoded LCU is applied to the corresponding LCU. Therefore, by encoding stored_filter_idx, encoding of syntax information regarding the second filter set applied to the corresponding LCU can be simplified.

According to the syntaxes of FIGS. 9, 10, and 11, it is not necessary to encode the same second filter coefficient information 15 redundantly, while the already encoded second filter coefficient information 15 is used for reference. Need to save. That is, the moving image encoding device and the moving image decoding device require a storage unit (for example, a buffer) that stores the already encoded second filter coefficient information 15.

Constraints can be imposed on the second filter coefficient information 15 to be saved in order to save the capacity of the storage unit. For example, the second filter coefficient information 15 may be stored in the storage unit only for a maximum of N second filter sets within the same picture or the same LCU line, for example. In this case, any one of a maximum of N second filter sets can be referred to in each LCU.

It should be noted that the (N + 1) th and subsequent second filter sets may not be referred to, or may be referred to by overwriting part of the second filter coefficient information 15 stored in the storage unit. That is, when the second filter coefficient information 15 is newly stored in a state where the second filter coefficient information 15 of the N second filter sets is stored in the storage unit, The second filter coefficient information 15 of any one of the second filter sets may be overwritten. The second filter coefficient information 15 to be overwritten may be the most recently saved, the least frequently referenced information, or the most recently referenced information. . In any case, a design is required so that the moving picture decoding apparatus can identify the second filter coefficient information 15 of the second filter set applied to each LCU.

Further, according to the syntax of FIG. 11, the first filter coefficient information 13 is also referred to using stored_filter_idx. Therefore, the same restrictions as the second filter coefficient information 15 can be imposed on the first filter coefficient information 13. That is, in the storage unit, for example, filter coefficient information (that is, the first filter coefficient information 13 or the first filter set 13 or the second filter set) is limited to a maximum of N filter sets (first filter set or second filter set) within a picture or an LCU line. Second filter coefficient information 15) may be stored. However, as described above, if the first filter set is set semi-optimally for the entire picture, many LCUs refer to the first filter coefficient information 13, so that the overhead of the encoded data 17 is effectively reduced. Can be reduced. Therefore, the first filter coefficient information 13 may be excluded from overwriting.

Further, the above-described limit number (= N) and the method of selecting overwritten filter coefficient information may be determined in advance between the moving image encoding device and the moving image decoding device, respectively. It may be specified by signaling necessary information from the encoding device to the video decoding device. The signaled information may be encoded in SPS, PPS, APS, slice header or LCU data.

Note that the syntaxes described above are merely examples, and various syntax information can be changed, deleted, or added without departing from the scope of the present embodiment. For example, picture_based_filter_flag, lcu_based_filter_flag, and new_filter_flag may be flags or other information. In addition, a plurality of pieces of syntax information can be specified together by an index.

It is also possible to prepare a plurality of types of LCU syntax and select the applied LCU syntax in units of slices, for example. However, a design is required so that the moving picture decoding apparatus can identify the selected LCU syntax.

When the image is composed of a plurality of components, syntax information may be generated for each component, or common syntax information may be generated between two or more components. Also, the syntax structure may be different for each component. For example, the syntax structure of a certain component may be obtained by changing some syntax elements of the syntax structure of another component, or by deleting some syntax elements from the syntax structure of another component. Alternatively, a part of syntax elements may be added to the syntax structure of other components.

In the above description, the first filter coefficient information 13 is encoded in the APS, and the filter switching information 14 and the second filter coefficient information 15 are encoded in the LCU level syntax. However, if the same or similar effect as the above syntax structure can be obtained, a different syntax structure may be adopted. For example, the first filter coefficient information 13 may be encoded in a PPS or slice header instead of APS. Alternatively, the first filter coefficient information 13 may be encoded in an LCU syntax corresponding to a predetermined LCU (for example, a head LCU in a picture or a slice).

The moving picture encoding apparatus in FIG. 1 can perform encoding processing as follows, for example.
Specifically, the prediction unit 101, the subtraction unit 102, the transform / quantization unit 103, the inverse quantization / inverse transform unit 105, and the addition unit 106 can operate as follows.

The prediction unit 101 generates the predicted image 11 based on the loop filter processed image 19, for example. The subtraction unit 102 generates a prediction error image 12 by subtracting the prediction image 11 from the input image 10. The transform / quantization unit 103 performs transform and quantization on the prediction error image 12 to generate a quantized transform coefficient. The quantized transform coefficient is encoded by the entropy encoding unit 104. The inverse quantization / inverse transform unit 105 generates a prediction error image by performing inverse quantization and inverse transform on the quantized transform coefficient. The addition unit 106 generates a decoded image 16 by adding the prediction error image to the prediction image 11.

This operation corresponds to so-called hybrid coding including prediction processing and conversion processing. However, the moving picture encoding apparatus according to the present embodiment does not necessarily have to perform hybrid encoding. For example, when hybrid coding is replaced with DPCM (Differential Pulse Code Modulation), prediction processing based on neighboring pixels may be performed instead of unnecessary processing being omitted.

The entropy encoding unit 104, the loop filter information generation unit 107, the loop filter processing unit 108, and the first filter setting unit 109 operate as shown in FIG. 12, for example. The process of FIG. 12 is performed in units of pictures.

The entropy encoding unit 104, the loop filter information generation unit 107, and the loop filter processing unit 108 obtain the first filter coefficient information 13 set for the picture from the first filter buffer 110 (step S101). The entropy encoding unit 104 encodes the first filter coefficient information 13 acquired in step S101 according to the syntax of FIG. 7, for example (step S102).

After step S102, an encoding process is performed on an unencoded LCU in the picture (step S103). The encoding process performed in step S103 is, for example, the above-described hybrid encoding. That is, the entropy encoding unit 104 encodes the quantization transform coefficient and the encoding parameter of the processing target LCU.

Among the loop filter information generation unit 107, the filter setting information generation unit 112 generates filter setting information 18 of the processing target LCU based on the input image 10 and the decoded image 16 (step S104).

Of the loop filter information generation unit 107, the second filter setting unit 113 sets the second filter coefficient information 15 for the LCU to be processed based on the filter setting information 18 generated in step S104 (step S105). .

Of the loop filter information generation unit 107, the filter switching information generation unit 114 includes the input image 10, the decoded image 16, the first filter coefficient information 13 acquired in step S101, and the second filter coefficient generated in step S105. Based on the information 15, the filter switching information 14 of the LCU to be processed is generated (step 106). For simplification, in the operation example of FIG. 12, the filter switching information 14 is information indicating which of the first filter set and the second filter set is applied to the processing target LCU. .

If the filter switching information 14 generated in step S106 indicates that the first filter set is applied to the LCU to be processed, the process proceeds to step S108 (step S107). On the other hand, if the filter switching information 14 generated in step S106 indicates that the second filter set is applied to the LCU to be processed, the process proceeds to step S110 (step S107).

In step S108, the loop filter processing unit 108 generates the loop filter processed image 19 by applying the first filter set to the LCU to be processed using the first filter coefficient information 13 acquired in step S101. Further, the entropy encoding unit 104 encodes the filter switching information 14 generated in step S014 according to the syntax of FIG. 8, FIG. 9, FIG. 10, or FIG. 11, for example (step S109).

If the encoding process for all the LCUs in the picture is completed at the time when Step S108 and Step S109 are completed, the process proceeds to Step S113 (Step S112). On the other hand, if the encoding process for all the LCUs in the picture has not been completed when Step S108 and Step S109 are completed, the process returns to Step S103 (Step S112).

In step S110, the loop filter processing unit 108 generates the loop filter processed image 19 by applying the second filter set to the LCU to be processed using the second filter coefficient information 15 set in step S105. Further, the entropy encoding unit 104 encodes the filter switching information 14 generated in step S104 and the second filter coefficient information 15 set in step S105, for example, according to the syntax of FIG. 8, FIG. 9, FIG. (Step S111).

If the encoding process for all the LCUs in the picture is completed at the time when Step S110 and Step S111 are completed, the process proceeds to Step S113 (Step S112). On the other hand, if the encoding process for all the LCUs in the picture has not been completed when Step S110 and Step S111 are completed, the process returns to Step S103 (Step S112).

In step S113, the first filter setting unit 109 sets the first filter coefficient information 13 used in the subsequent picture based on the filter setting information 18 of each LCU generated by repeating step S104. The first filter setting unit 109 stores the first filter coefficient information 13 set in step S113 in the first filter buffer 110, and the process ends (step S114).

As described above, the moving picture encoding apparatus according to the first embodiment uses the first filter set set in units of pictures and the second filter set set in units of pixel blocks for each pixel block. Selectively apply to. Therefore, according to this moving image encoding apparatus, the overhead of encoded data can be effectively reduced. Further, the first filter coefficient information can be encoded before the encoding of each pixel block starts. Therefore, according to this moving image encoding device, the encoded data of each pixel block can be sequentially output to reduce the delay associated with the moving image encoding process.

(Video decoding device)
As illustrated in FIG. 13, the moving picture decoding apparatus according to the first embodiment includes a moving picture decoding unit 2000 and a decoding control unit 207. The moving image decoding unit 2000 includes an entropy decoding unit 201, an inverse quantization / inverse transform unit 202, a predicted image generation unit 203, an addition unit 204, a first filter buffer 205, and a loop filter processing unit 206. . The decoding control unit 207 controls the operation of each unit of the moving image decoding unit 2000.

The entropy decoding unit 201 inputs the encoded data 20 from the outside of the video decoding device (for example, a communication system or a storage system). The encoded data 20 is the same as or similar to the encoded data 17 described above. The entropy decoding unit 201 performs entropy decoding on the encoded data 20, thereby performing quantization transform coefficients, encoding parameters, first filter coefficient information 22, filter switching information 23, second filter coefficient information 24, Is generated. The entropy decoding unit 201 may use, for example, the syntax of FIG. 7 in order to decode the first filter coefficient information 22. Further, the entropy decoding unit 201 may use, for example, the syntax of FIG. 8, FIG. 9, FIG. 10, or FIG. 11 to decode the filter switching information 23 and the second filter coefficient information 24.

The first filter coefficient information 22 may be the same as or similar to the first filter coefficient information 13. The filter switching information 23 may be the same as or similar to the filter switching information 14. The second filter coefficient information 24 may be the same as or similar to the second filter coefficient information 15.

The entropy decoding unit 201 outputs the quantized transform coefficient to the inverse quantization / inverse transform unit 202, outputs the encoding parameter to the decoding control unit 207, and sends the first filter coefficient information 22 to the first filter buffer 205. The filter switching information 23 and the second filter coefficient information 24 are output to the loop filter processing unit 206.

The inverse quantization / inverse transform unit 202 inputs the quantized transform coefficient from the entropy decoding unit 201. The inverse quantization / inverse transform unit 202 inversely quantizes the quantized transform coefficient to obtain a transform coefficient. Further, the inverse quantization / inverse transform unit 202 performs an inverse transform process on the transform coefficient to obtain a prediction error image. The inverse quantization / inverse transform unit 202 outputs the prediction error image to the addition unit 204. The inverse quantization / inverse transformation unit 202 performs the same or similar processing as the above-described inverse quantization / inverse transformation unit 105. That is, the inverse quantization is performed based on the quantization parameter set by the decoding control unit 207. Further, the inverse conversion process is determined by the conversion process performed on the encoding side. For example, the inverse transform process is IDCT, inverse wavelet transform, or the like.

The predicted image generation unit 203 performs output image prediction processing in units of pixel blocks, for example, and generates a predicted image. The predicted image generation unit 203 may perform output image prediction processing based on a loop filter processed image 25 described later. The predicted image generation unit 203 performs the same or similar processing as the predicted image generation unit 101 described above. The predicted image generation unit 203 outputs the predicted image to the adding unit 204.

The addition unit 204 inputs a prediction image from the prediction image generation unit 203 and inputs a prediction error image from the inverse quantization / inverse conversion unit 202. The adding unit 204 adds the prediction error image to the prediction image to generate the decoded image 21. The adding unit 204 outputs the decoded image 21 to the loop filter processing unit 206.

The first filter coefficient information 22 stored in the first filter buffer 205 is read by the loop filter processing unit 206 as necessary. Note that if the loop filter processing unit 206 has a function of storing the first filter coefficient information 22, the first filter buffer 205 may be omitted. In such a case, the entropy decoding unit 201 outputs the first filter coefficient information 22 to the loop filter processing unit 206.

The loop filter processing unit 206 receives the decoded image 21 from the adding unit 204 in units of pixel blocks, receives the filter switching information 23 and the second filter coefficient information 24 from the entropy decoding unit 201, and receives the first filter buffer 205 from the first filter buffer 205. The filter coefficient information 22 is input.

The loop filter processing unit 206 applies one of the first filter set and the second filter set based on the filter switching information 23 corresponding to the pixel block to be processed. Specifically, the loop filter processing unit 206 performs a loop filter process on the pixel block to be processed using the first filter coefficient information 22 or the second filter coefficient information 24, so that the pixels in the loop filter processed image 25 are processed. Generate a block. If the filter switching information 23 indicates that the loop filter process is not applied to the pixel block to be processed, the loop filter processing unit 206 omits the loop filter process for the pixel block to be processed. That is, the loop filter processing unit 206 performs the same or similar loop filter processing as the loop filter processing unit 108.

The loop filter processing unit 206 gives the loop filter processed image 25 as an output image to the outside (for example, a display system) of the moving image decoding apparatus. Further, the loop filter processed image 25 may be stored in a storage unit (not shown) (for example, a buffer) accessible by the predicted image generation unit 203. The loop filter processed image 25 is read as a reference image by the predicted image generation unit 203 as necessary, and is used for the prediction process.

The decoding control unit 207 receives the encoding parameter from the entropy decoding unit 201. The decoding control unit 207 performs decoding timing control, encoding block division control, quantization control, mode control, and the like based on the encoding parameters.

The moving picture decoding apparatus in FIG. 2 can perform the decoding process as follows, for example.
When starting to decode a picture, the entropy decoding unit 201 decodes the first filter coefficient information 22 set to the picture in accordance with the syntax of FIG. 7, for example. Then, the entropy decoding unit 201 starts decoding the pixel block in the picture. Specifically, the entropy decoding unit 201 decodes the quantized transform coefficient and the encoding parameter of the pixel block. Furthermore, the entropy decoding unit 201 decodes the filter switching information 23 of the pixel block according to the syntax of FIG. 8, FIG. 9, FIG. 10, or FIG. The entropy decoding unit 201 further decodes the second filter coefficient information 15 if the filter switching information 23 indicates that the second filter set is applied to the pixel block.

Quantization transform coefficients and encoding parameters of the pixel block are processed based on the above-described hybrid encoding. That is, the inverse quantization / inverse transform unit 202 generates a prediction error image by performing inverse quantization and inverse transform on the quantized transform coefficient. The prediction unit 203 generates a prediction image based on the loop filter processed image 25, for example. The adding unit 204 generates the decoded image 21 by adding the prediction error image to the prediction image.

The loop filter processing unit 206 applies one of the first filter set and the second filter set based on the filter switching information 23 corresponding to the pixel block in the decoded image 21. The loop filter processing unit 206 generates a pixel block in the loop filter processed image 25 by performing a loop filter process on the pixel block to be processed using the first filter coefficient information 22 or the second filter coefficient information 24.

As described above, the video decoding device according to the first embodiment generates an output image by decoding the encoded data from the video encoding device according to the first embodiment. Therefore, according to this moving picture decoding apparatus, the overhead of encoded data can be effectively reduced.

(Second Embodiment)
(Moving picture encoding device)
As illustrated in FIG. 14, the video encoding apparatus according to the second embodiment includes a video encoding unit 3000 and an encoding control unit 111. The moving image coding unit 3000 includes a predicted image generation unit 101, a subtraction unit 102, a transform / quantization unit 103, an entropy coding unit 104, an inverse quantization / inverse transform unit 105, an adder unit 106, A loop filter information generation unit 307, a loop filter processing unit 308, a first filter setting unit 109, a first filter buffer 110, a deblocking filter processing unit 315, and a SAO (Sample Adaptive Offset) processing unit 316 are provided. . The encoding control unit 111 controls the operation of each unit of the moving image encoding unit 3000.

The entropy encoding unit 104 in FIG. 14 differs from the entropy encoding unit 104 in FIG. 1 in that the filter switching information 14 and the second filter coefficient information 15 are input from the loop filter information generation unit 307 instead of the loop filter information generation unit 107. Is different.

14 differs from the addition unit 106 in FIG. 1 in that the decoded image 16 is output to the deblocking filter processing unit 315 instead of the loop filter information generation unit 107 and the loop filter processing unit 108.

14 is different from the first filter setting unit 109 in FIG. 1 in that the filter setting information 18 is input from the loop filter information generation unit 307 instead of the loop filter information generation unit 107.

The loop filter information generation unit 307 acquires the input image 10 in units of pixel blocks from the outside of the video encoding device, inputs the first filter coefficient information 13 from the first filter buffer 110, and will be described later from the SAO processing unit 316. SAO-processed images are input in units of pixel blocks.

The loop filter information generation unit 307 generates filter setting information 18 corresponding to the pixel block to be processed based on the SAO processed image and the input image 10. Further, the loop filter information generation unit 307 generates the second filter coefficient information 15 corresponding to the pixel block to be processed based on the filter setting information 18. Further, the loop filter information generation unit 307 generates filter switching information 14 corresponding to the pixel block to be processed based on the SAO processed image, the input image 10, the first filter coefficient information 13, and the second filter coefficient information 15. .

The loop filter information generation unit 307 outputs the filter switching information 14 and the second filter coefficient information 15 to the entropy encoding unit 104 and the loop filter processing unit 308. The loop filter information generation unit 307 outputs the filter setting information 18 to the first filter setting unit 109.

The loop filter processing unit 308 inputs the SAO processed image from the SAO processing unit 316 in units of pixel blocks, receives the filter switching information 14 and the second filter coefficient information 15 from the loop filter information generation unit 307, and the first filter buffer 110. The first filter coefficient information 13 is input.

The loop filter processing unit 308 applies one of the first filter set and the second filter set based on the filter switching information 14 corresponding to the pixel block to be processed. Specifically, the loop filter processing unit 308 performs a loop filter process on the pixel block to be processed using the first filter coefficient information 13 or the second filter coefficient information 15, so that the pixels in the loop filter processed image 19 are processed. Generate a block. If the filter switching information 14 indicates that the loop filter processing is not applied to the pixel block to be processed, the loop filter processing unit 308 omits the loop filter processing for the pixel block to be processed.

The deblocking filter processing unit 315 inputs the decoded image 16 from the addition unit 106. The deblocking filter processing unit 315 performs a deblocking filter process on the decoded image 16 to generate a deblocking filter process image. The deblocking filter processing unit 315 outputs the deblocking filter processing image to the SAO processing unit 316.

Here, the deblocking filter process performed by the deblocking filter processing unit 315 may be a process of applying a smoothing filter to a block boundary in the decoded image 16, for example. This deblocking filter processing generally brings about an image quality improvement effect such as suppression of block distortion included in the decoded image 16.

The SAO processing unit 316 inputs a deblocking filter processing image from the deblocking filter processing unit 315. The SAO processing unit 316 generates a SAO processed image by performing SAO processing on the deblocking filter processed image. The SAO processing unit 316 outputs the SAO processed image to the loop filter information generation unit 307 and the loop filter processing unit 308.

Here, the SAO processing performed by the SAO processing unit 316 sets an offset value for each pixel in the deblocking filtered image based on a comparison of the pixel values between the pixel and the surrounding pixels, The offset value may be added to the pixel value of each pixel.

As described above, the moving image encoding apparatus according to the second embodiment performs the first image processing on an image obtained by performing deblocking filter processing and SAO processing on a decoded image instead of the decoded image. Loop filter processing that is the same as or similar to that of the moving image encoding apparatus according to the embodiment is performed. Therefore, according to this moving image encoding apparatus, the image quality of the predicted image can be improved and the encoding efficiency can be improved.

(Video decoding device)
As illustrated in FIG. 15, the moving picture decoding apparatus according to the second embodiment includes a moving picture decoding unit 4000 and a decoding control unit 207. The video decoding unit 4000 includes an entropy decoding unit 201, an inverse quantization / inverse transformation unit 202, a predicted image generation unit 203, an addition unit 204, a first filter buffer 205, a loop filter processing unit 406, A blocking filter processing unit 408 and an SAO processing unit 409 are provided. The decoding control unit 207 controls the operation of each unit of the moving image decoding unit 4000.

15 differs from the entropy decoding unit 201 of FIG. 13 in that the filter switching information 23 and the second filter coefficient information 24 are output to the loop filter processing unit 406 instead of the loop filter processing unit 206. The entropy decoding unit 201 of FIG. The addition unit 204 in FIG. 15 is different from the addition unit 204 in FIG. 13 in that the decoded image 21 is output to the deblocking filter processing unit 408 instead of the loop filter processing unit 206.

The loop filter processing unit 406 receives the SAO processed image from the SAO processing unit 409 in pixel block units, receives the filter switching information 23 and the second filter coefficient information 24 from the entropy decoding unit 201, and receives the first filter buffer 205 from the first filter buffer 205. 1 filter coefficient information 22 is input.

The loop filter processing unit 406 applies one of the first filter set and the second filter set based on the filter switching information 23 corresponding to the pixel block to be processed. Specifically, the loop filter processing unit 406 performs a loop filter process on the pixel block to be processed using the first filter coefficient information 22 or the second filter coefficient information 24, so that the pixels in the loop filter processed image 25 are processed. Generate a block. If the filter switching information 23 indicates that the loop filter processing is not applied to the pixel block to be processed, the loop filter processing unit 406 omits the loop filter processing for the pixel block to be processed.

The loop filter processing unit 406 gives the loop filter processed image 25 as an output image to the outside of the video decoding device (for example, a display system). Further, the loop filter processed image 25 may be stored in a storage unit (not shown) (for example, a buffer) accessible by the predicted image generation unit 203. The loop filter processed image 25 is read as a reference image by the predicted image generation unit 203 as necessary, and is used for the prediction process.

The deblocking filter processing unit 408 inputs the decoded image 21 from the adding unit 204. The deblocking filter processing unit 408 generates a deblocking filter processed image by performing a deblocking filter process on the decoded image 21. The deblocking filter processing unit 408 outputs the deblocking filter processing image to the SAO processing unit 409. Note that the deblocking filter processing unit 408 performs the same or similar deblocking filter processing as the deblocking filter processing unit 315.

The SAO processing unit 409 inputs a deblocking filter processing image from the deblocking filter processing unit 408. The SAO processing unit 409 generates a SAO processed image by performing SAO processing on the deblocking filter processed image. The SAO processing unit 409 outputs the SAO processed image to the loop filter processing unit 406. Note that the SAO processing unit 409 performs the same or similar SAO processing as the SAO processing unit 316.

As described above, the moving picture decoding apparatus according to the second embodiment performs the first implementation described above on an image obtained by performing deblocking filter processing and SAO processing on the decoded image instead of the decoded image. The same or similar loop filter processing as the moving picture decoding apparatus according to the embodiment is performed. Therefore, according to this moving image encoding apparatus, the image quality of the predicted image can be improved and the encoding efficiency can be improved.

(Third embodiment)
(Moving picture encoding device)
As illustrated in FIG. 16, the moving picture encoding apparatus according to the third embodiment includes a moving picture encoding unit 5000 and an encoding control unit 111. The moving image encoding unit 5000 includes a predicted image generating unit 101, a subtracting unit 102, a transform / quantization unit 103, an entropy encoding unit 104, an inverse quantization / inverse transform unit 105, an addition unit 106, A loop filter information generation unit 507, a loop filter processing unit 508, a first filter setting unit 109, a first filter buffer 110, a deblocking filter processing unit 315, and an SAO processing unit 316 are provided. The encoding control unit 111 controls the operation of each unit of the moving image encoding unit 5000.

The entropy encoding unit 104 in FIG. 16 differs from the entropy encoding unit 104 in FIG. 1 in that the filter switching information 14 and the second filter coefficient information 15 are input from the loop filter information generation unit 507 instead of the loop filter information generation unit 107. Is different.

16 outputs the decoded image 16 to the deblocking filter processing unit 315, the loop filter information generation unit 507, and the loop filter processing unit 508 instead of the loop filter information generation unit 107 and the loop filter processing unit 108. This is different from the adding unit 106 in FIG.

16 is different from the first filter setting unit 109 in FIG. 1 in that the filter setting information 18 is input from the loop filter information generation unit 507 instead of the loop filter information generation unit 107.

The loop filter information generation unit 507 acquires the input image 10 from the outside of the video encoding device in units of pixel blocks, inputs the decoded image 16 from the addition unit 106 in units of pixel blocks, and receives the first image from the first filter buffer 110. The filter coefficient information 13 is input, and the SAO processing image is input from the SAO processing unit 316 in pixel block units.

The loop filter information generation unit 507 generates filter setting information 18 corresponding to the pixel block to be processed based on the SAO processed image, the input image 10 and the decoded image 16. Further, the loop filter information generation unit 507 generates the second filter coefficient information 15 corresponding to the pixel block to be processed based on the filter setting information 18. Further, the loop filter information generation unit 507 performs filter switching information corresponding to the pixel block to be processed based on the SAO processed image, the input image 10, the first filter coefficient information 13, the second filter coefficient information 15, and the decoded image 16. 14 is generated.

The loop filter information generation unit 507 outputs the filter switching information 14 and the second filter coefficient information 15 to the entropy encoding unit 104 and the loop filter processing unit 508. The loop filter information generation unit 507 outputs the filter setting information 18 to the first filter setting unit 109.

The loop filter processing unit 508 inputs the decoded image 16 from the adder unit 106 in units of pixel blocks, inputs the SAO processed image from the SAO processing unit 316 in units of pixel blocks, and receives filter switching information 14 and from the loop filter information generation unit 507. The second filter coefficient information 15 is input, and the first filter coefficient information 13 is input from the first filter buffer 110.

The loop filter processing unit 508 applies one of the first filter set and the second filter set based on the filter switching information 14 corresponding to the pixel block to be processed. Specifically, the loop filter processing unit 508 performs a loop filter process on the pixel block to be processed using the first filter coefficient information 13 or the second filter coefficient information 15, so that the pixels in the loop filter processed image 19 are processed. Generate a block. If the filter switching information 14 indicates that the loop filter process is not applied to the pixel block to be processed as described above, the loop filter processing unit 508 omits the loop filter process for the pixel block to be processed.

Here, the loop filter processing unit 508 performs loop filter processing on the decoded image 16 and the SAO processed image. For example, the loop filter processing unit 508 may perform loop filter processing on an image obtained by performing weighted averaging of each pixel value of the decoded image 16 and each pixel value of the SAO processed image using appropriate weights. it can.

Block distortion generated by encoding can be generally suppressed by deblocking filter processing. However, in the deblocking filter process, a high-intensity low-pass filter is applied, and high-frequency components (for example, edge components and texture components) included in the input image 10 may be deteriorated. By performing the loop filter process on the images before and after the deblocking filter process (that is, the decoded image 16 and the SAO process image), it is possible to compensate for partial image quality degradation that has occurred through the deblocking filter process. That is, an image quality improvement effect can be obtained.

Further, the image to be subjected to the loop filter process may be switched in units such as a sequence, a picture, and a slice. For example, the loop filter process may be performed on only the SAO processed image in a certain slice, and the loop filter process may be performed on the decoded image 16 and the SAO processed image in another slice. In order to allow the video decoding device to identify the switching of the image to be subjected to the loop filter process, information indicating the switching of the image to be the target of the loop filter process may be encoded in units such as a sequence, a picture, and a slice. Is possible.

Note that the above-described partial deterioration in image quality is not limited to the deblocking filter process, and may be caused by various filter processes. Therefore, the loop filter process may be performed on the images before and after the arbitrary filter process. Further, when a plurality of filter processes are performed on the decoded image 16 before the loop filter process, the loop filter process may be performed on images before and after any one or more filter processes.

As described above, the moving image encoding apparatus according to the third embodiment targets the images before and after the filter process (for example, the deblocking filter process and the SAO process), and the moving image according to the first embodiment described above. The same or similar loop filter processing as that of the image encoding device is performed. Therefore, according to this moving image encoding apparatus, the image quality of the predicted image can be improved and the encoding efficiency can be improved.

(Video decoding device)
As illustrated in FIG. 17, the video decoding device according to the third embodiment includes a video decoding unit 6000 and a decoding control unit 207. The video decoding unit 6000 includes an entropy decoding unit 201, an inverse quantization / inverse transformation unit 202, a predicted image generation unit 203, an addition unit 204, a first filter buffer 205, a loop filter processing unit 606, A blocking filter processing unit 408 and an SAO processing unit 409 are provided. The decoding control unit 207 controls the operation of each unit of the moving image decoding unit 6000.

17 differs from the entropy decoding unit 201 in FIG. 13 in that the filter switching information 23 and the second filter coefficient information 24 are output to the loop filter processing unit 606 instead of the loop filter processing unit 206. The entropy decoding unit 201 in FIG. 17 is different from the addition unit 204 of FIG. 13 in that the decoded image 21 is output to the deblocking filter processing unit 408 instead of the loop filter processing unit 206.

The loop filter processing unit 606 receives the decoded image 21 from the adding unit 204 in units of pixel blocks, inputs the SAO processed image from the SAO processing unit 409 in units of pixel blocks, and receives the filter switching information 23 and the second information from the entropy decoding unit 201. The filter coefficient information 24 is input, and the first filter coefficient information 22 is input from the first filter buffer 205.

The loop filter processing unit 606 applies one of the first filter set and the second filter set based on the filter switching information 23 corresponding to the pixel block to be processed. Specifically, the loop filter processing unit 606 performs a loop filter process on the pixel block to be processed using the first filter coefficient information 22 or the second filter coefficient information 24, so that the pixels in the loop filter processed image 25 are processed. Generate a block. That is, the loop filter processing unit 606 performs the same or similar loop filter processing as the loop filter processing unit 508. If the filter switching information 23 indicates that the loop filter processing is not applied to the pixel block to be processed, the loop filter processing unit 606 omits the loop filter processing for the pixel block to be processed.

The loop filter processing unit 606 gives the loop filter processed image 25 as an output image to the outside of the video decoding device (for example, a display system). Further, the loop filter processed image 25 may be stored in a storage unit (not shown) (for example, a buffer) accessible by the predicted image generation unit 203. The loop filter processed image 25 is read as a reference image by the predicted image generation unit 203 as necessary, and is used for the prediction process.

As described above, the moving picture decoding apparatus according to the third embodiment is directed to the moving picture decoding according to the first embodiment described above for the images before and after the filtering process (for example, the deblocking filtering process and the SAO process). Performs the same or similar loop filter processing as the device. Therefore, according to this moving image decoding apparatus, it is possible to improve the encoding efficiency by improving the image quality of the predicted image.

(Fourth embodiment)
In the video decoding device according to the first, second, or third embodiment described above, the loop filter processed image 25 is provided as an output image outside the video decoding device (for example, a display system). However, the decoded image 21 may be given to the outside of the moving image decoding apparatus as an output image instead of the loop filter processed image 25.

(Video decoding device)
As illustrated in FIG. 18, the video decoding device according to the fourth embodiment includes a video decoding unit 7000 and a decoding control unit 207. The video decoding unit 7000 includes an entropy decoding unit 201, an inverse quantization / inverse transformation unit 202, a predicted image generation unit 203, an addition unit 204, a first filter buffer 205, and a loop filter processing unit 206. . The decoding control unit 207 controls the operation of each unit of the moving image decoding unit 7000.

18 adds the decoded image 21 to the loop filter processing unit 206 in the same manner as the addition unit 204 in FIG. Further, the adding unit 204 in FIG. 18 provides the decoded image 21 as an output image to the outside of the moving image decoding apparatus. The loop filter processing unit 206 in FIG. 18 is different from the loop filter processing unit 206 in FIG. 13 in that the loop filter processed image 25 is not given as an output image to the outside of the video decoding device.

As described above, the moving picture decoding apparatus according to the fourth embodiment gives the decoded picture before the loop filter processing to the outside of the moving picture decoding apparatus as an output picture. Therefore, according to this moving image decoding apparatus, an output image can be given to the outside with a low delay.

(Fifth embodiment)
The loop filter processing described in the first, second, or third embodiment can be replaced with post filter processing. That is, the moving picture encoding apparatus according to the fifth embodiment generates filter information (for example, first filter coefficient information 13, filter switching information 14, and second filter coefficient information 15) for post filter processing. Then, the video decoding device according to the fifth embodiment performs post-filter processing based on the filter information.

(Moving picture encoding device)
As illustrated in FIG. 19, the moving picture coding apparatus according to the fifth embodiment includes a moving picture coding unit 8000 and a coding control unit 111. The moving image encoding unit 8000 includes a predicted image generation unit 101, a subtraction unit 102, a transform / quantization unit 103, an entropy encoding unit 104, an inverse quantization / inverse transform unit 105, an addition unit 106, A post filter information generation unit 807, a first filter setting unit 109, and a first filter buffer 110 are provided. The encoding control unit 111 controls the operation of each unit of the moving image encoding unit 8000.

19 is different from the predicted image generation unit 101 in FIG. 1 in that the predicted image generation unit 101 in FIG. 19 performs a prediction process based on the decoded image 16 instead of the loop filter processed image 19. The entropy encoding unit 104 in FIG. 19 is different from the entropy encoding unit 104 in FIG. 1 in that the filter switching information 14 and the second filter coefficient information 15 are input from the post filter information generation unit 807 instead of the loop filter information generation unit 107. Is different.

19 is different from the addition unit 106 in FIG. 1 in that the decoded image 16 is output to the post filter information generation unit 807 instead of the loop filter information generation unit 107 and the loop filter processing unit 108. In addition, the decoded image 16 may be stored in a storage unit (not illustrated) (for example, a buffer) that can be accessed by the predicted image generation unit 101. The decoded image 16 is read as a reference image by the predicted image generation unit 101 as necessary, and is used for the prediction process.

19 is different from the first filter setting unit 109 in FIG. 1 in that the filter setting information 18 is input from the post filter information generation unit 807 instead of the loop filter information generation unit 107.

The post filter information generation unit 807 acquires the input image 10 in units of pixel blocks from the outside of the video encoding device, inputs the decoded image 16 in units of pixel blocks from the addition unit 106, and receives the first image from the first filter buffer 110. The filter coefficient information 13 is input. The post filter information generation unit 807 performs the same or similar processing as the loop filter information setting unit 107, for example. The post filter information generation unit 807 outputs the filter switching information 14 and the second filter coefficient information 15 to the entropy encoding unit 104. The post filter information generation unit 807 outputs the filter setting information 18 to the first filter setting unit 109.

As described above, the moving picture encoding apparatus according to the fifth embodiment uses the filter information for the loop filter processing in the first, second, or third embodiment described above as the filter for the post filter processing. Generate as information. Therefore, according to this moving image encoding device, in the moving image encoding device and the moving image decoding device in which post filter processing is used instead of loop filter processing, the same as in the first, second, or third embodiment or Similar effects can be obtained.

(Video decoding device)
As illustrated in FIG. 20, the video decoding device according to the fifth embodiment includes a video decoding unit 9000 and a decoding control unit 207. The moving picture decoding unit 9000 includes an entropy decoding unit 201, an inverse quantization / inverse transformation unit 202, a predicted image generation unit 203, an addition unit 204, a first filter buffer 205, and a post filter processing unit 906. . The decoding control unit 207 controls the operation of each unit of the moving image decoding unit 9000.

20 is different from the entropy decoding unit 201 in FIG. 13 in that the filter switching information 23 and the second filter coefficient information 24 are output to the post filter processing unit 906 instead of the loop filter processing unit 206. The entropy decoding unit 201 in FIG. The predicted image generation unit 203 in FIG. 20 is different from the predicted image generation unit 203 in FIG. 13 in that a prediction process is performed based on the decoded image 21 instead of the loop filter processed image 25.

20 is different from the addition unit 204 of FIG. 13 in that the decoded image 21 is output to the post filter processing unit 906 instead of the loop filter processing unit 206. In addition, the decoded image 21 may be stored in a storage unit (not shown) (for example, a buffer) that can be accessed by the predicted image generation unit 203. The decoded image 21 is read as a reference image by the predicted image generation unit 203 as necessary, and is used for the prediction process.

The post filter processing unit 906 inputs the decoded image 21 from the adder unit 204 in units of pixel blocks, receives the filter switching information 23 and the second filter coefficient information 24 from the entropy decoding unit 201, and receives the first filter buffer 205 from the first filter buffer 205. The filter coefficient information 22 is input.

The post filter processing unit 906 applies one of the first filter set and the second filter set based on the filter switching information 23 corresponding to the pixel block to be processed. Specifically, the post-filter processing unit 906 performs post-filter processing on the pixel block to be processed using the first filter coefficient information 22 or the second filter coefficient information 24, so that the pixels in the post-filter processed image 35 are processed. Generate a block. If the filter switching information 23 indicates that post-filter processing is not applied to the pixel block to be processed, the post-filter processing unit 906 omits post-filter processing for the pixel block to be processed. The post filter processing unit 906 gives the post filter processed image 35 as an output image to the outside of the video decoding device (for example, a display system).

As described above, the moving picture decoding apparatus according to the fifth embodiment performs post filter processing that is the same as or similar to the loop filter processing in the first, second, or third embodiment described above. Therefore, according to this moving image encoding device, in the moving image encoding device and the moving image decoding device in which post filter processing is used instead of loop filter processing, the same as in the first, second, or third embodiment or Similar effects can be obtained.

It should be noted that the various processes described in the above-described embodiments can also be realized by using a program (that is, software) in which corresponding instructions are described. Specifically, a computer (or an embedded system) may function as a moving picture encoding apparatus and a moving picture decoding apparatus according to each embodiment by installing and executing this program. Instructions corresponding to various processes described in the above-described embodiments are described as programs that can be executed by a computer.

The program can be a magnetic disk (eg, flexible disk (registered trademark), hard disk, etc.), optical disk (CD-ROM, CD-R, CD-RW, DVD-ROM, DVD ± R, DVD ± RW, etc.), semiconductor memory, It is recorded on a recording medium similar to these. Note that the program recording medium is not limited to the above example, and may be any computer-readable medium. Further, the program is not necessarily stored in one recording medium, and may be stored across a plurality of recording media. Further, the computer may download the program through a network (for example, a LAN (Local Area Network) or the Internet). In addition, the recording medium in which the program is stored may be independent from the computer, or may be for storing the program downloaded through the network (including temporary storage).

In addition, an OS (operating system), database management software, network MW (middleware), or other MW that runs on a computer is based on instructions described in the program, and a video encoding device according to each embodiment A part of the processing by the video decoding device may be executed.

In the above description, a computer or an embedded system is for executing each process in the present embodiment based on a program stored in a recording medium. Therefore, the computer or the embedded system may typically be one personal computer or a microcomputer, or may be a system formed by connecting a plurality of personal computers or microcomputers over a network.

The computer is not limited to a personal computer, and may be an arithmetic processing unit or a microcomputer included in an information processing device. In short, the computer is a generic term for devices or apparatuses that can realize the functions of the moving picture coding apparatus and the moving picture decoding apparatus according to each embodiment by a program.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Input image 11 ... Predicted image 12 ...

Prediction error image

13, 22 ... First

filter coefficient information

14, 23 ...

Filter switching information

15, 24 ... Second

filter coefficient information

16, 21 ... Decoded

image

17, 20 ... Encoded data 18 ...

Filter setting information

19, 25 ... Loop filter processed image 35 ... Post filter processed

image

101, 203 ... Predicted image Generation unit 102 ... subtraction unit 103 ... transform / quantization unit 104 ...

entropy encoding unit

105, 202 ... inverse quantization /

inverse transform unit

106, 204 ...

adder

107, 307, 507 ... Loop filter

information generation unit

108, 206, 308, 406, 508, 606 ... Loop filter processing unit 109 ... First filter setting unit 110, 2 DESCRIPTION OF SYMBOLS 5 ... 1st filter buffer 111 ... Encoding control part 112 ... Filter setting information generation part 113 ... 2nd filter setting part 114 ... Filter switching information generation part 115 ... Switch 116- ... Filter application unit 201... Entropy decoding unit 207... Decoding

control unit

315, 408 .. Deblocking

filter processing unit

316, 409... SAO processing unit 807. ..Post

filter processing unit

1000, 3000, 5000, 8000 ... moving

image encoding unit

2000, 4000, 6000, 7000, 9000 ... moving image decoding unit

Claims

Encoding first filter coefficient information indicating each filter coefficient of one or more filters included in a first filter set set for a decoded image;
When the loop filter process is applied to the pixel block to be processed in the decoded image, either the first filter set or the second filter set set for the pixel block to be processed is applied. Encoding the filter switching information indicating whether the first filter coefficient information is encoded,
When the second filter set is applied to the pixel block to be processed, second filter coefficient information indicating each filter coefficient of one or more filters included in the second filter set is stored in the first filter coefficient information. Encoding after one filter coefficient information is encoded;
Generating one pixel block in a reference image by applying one of the first filter set and the second filter set to the pixel block to be processed based on the filter switching information; A moving image encoding method provided.
The filter switching information indicates whether or not loop filter processing is applied to the pixel block to be processed. When loop filter processing is applied to the pixel block to be processed, the first filter set and The moving picture coding method according to claim 1, further showing which of the second filter sets is applied.
The moving picture encoding method according to claim 1, wherein the first filter coefficient information is encoded in a higher-order syntax than the second filter coefficient information.
The moving picture encoding method according to claim 1, wherein the filter coefficient includes only an offset value.
When the first filter set is applied to the pixel block to be processed, identification information having a first value referring to the first filter coefficient information is encoded as at least part of the switching information. ,
In the case where the second filter set is applied to the pixel block to be processed and the same second filter set as the already encoded pixel block is applied, the already encoded pixel block The identification information having a second value referring to the second filter coefficient information corresponding to is encoded as second filter coefficient information corresponding to the pixel block to be processed.
The moving image encoding method according to claim 1.
Storing the encoded first filter coefficient information in a storage unit;
Storing the encoded second filter coefficient information in the storage unit;
Further comprising
The total number of the first filter set corresponding to the first filter coefficient information stored in the storage unit and the second filter set corresponding to the second filter coefficient information stored in the storage unit is limited. A second filter set of the second filter coefficient information stored in the storage unit for storing the encoded second filter coefficient information in the storage unit when the number of the second filter coefficient information has been reached. The moving image coding method according to claim 5, wherein the corresponding second filter coefficient information is overwritten.
Decoding first filter coefficient information indicating each filter coefficient of one or more filters included in a first filter set set for a decoded image;
When the loop filter process is applied to the pixel block to be processed in the decoded image, either the first filter set or the second filter set set for the pixel block to be processed is applied. Decoding after the first filter coefficient information is decoded,
When the second filter set is applied to the pixel block to be processed, second filter coefficient information indicating each filter coefficient of one or more filters included in the second filter set is stored in the first filter coefficient information. Decoding after 1 filter coefficient information is decoded;
Generating one pixel block in a reference image by applying one of the first filter set and the second filter set to the pixel block to be processed based on the filter switching information; A moving picture decoding method provided.
The filter switching information indicates whether or not loop filter processing is applied to the pixel block to be processed. When loop filter processing is applied to the pixel block to be processed, the first filter set and The moving picture decoding method according to claim 7, further indicating which of the second filter sets is applied.
The moving picture decoding method according to claim 7, wherein the first filter coefficient information is decoded in a higher-order syntax than the second filter coefficient information.
The moving picture decoding method according to claim 7, wherein the filter coefficient includes only an offset value.
When the first filter set is applied to the pixel block to be processed, identification information having a first value referring to the first filter coefficient information is decoded as at least part of the switching information,
When the second filter set is applied to the pixel block to be processed and the same second filter set as the already decoded pixel block is applied, it corresponds to the already decoded pixel block The identification information having a second value referring to the second filter coefficient information is decoded as second filter coefficient information corresponding to the pixel block to be processed.
The moving image decoding method according to claim 7.
Storing the decoded first filter coefficient information in a storage unit;
Storing the decoded second filter coefficient information in the storage unit;
Further comprising
The total number of the first filter set corresponding to the first filter coefficient information stored in the storage unit and the second filter set corresponding to the second filter coefficient information stored in the storage unit is limited. When the number has reached the number, it corresponds to one second filter set among the second filter coefficient information stored in the storage unit in order to store the decoded second filter coefficient information in the storage unit The second filter coefficient information to be overwritten,
The moving image decoding method according to claim 11.
First filter coefficient information indicating each filter coefficient of one or more filters included in a first filter set set for a decoded image is encoded, and a loop filter is applied to a pixel block to be processed in the decoded image When the processing is applied, filter switching information indicating which of the first filter set and the second filter set set for the pixel block to be processed is applied is the first filter coefficient information. Are encoded, and when the second filter set is applied to the pixel block to be processed, each filter coefficient of one or more filters included in the second filter set is An encoding unit for encoding the second filter coefficient information to be encoded after the first filter coefficient information is encoded;
Loop filter processing for generating a pixel block in a reference image by applying one of the first filter set and the second filter set to the pixel block to be processed based on the filter switching information A moving image encoding apparatus.
First filter coefficient information indicating each filter coefficient of one or more filters included in a first filter set set for a decoded image is decoded, and a loop filter is applied to a pixel block to be processed in the decoded image When the processing is applied, filter switching information indicating which of the first filter set and the second filter set set for the pixel block to be processed is applied is the first filter coefficient information. When the second filter set is applied to the pixel block to be processed, each filter coefficient of one or more filters included in the second filter set is indicated. A decoding unit for decoding second filter coefficient information after the first filter coefficient information is decoded;
Loop filter processing for generating a pixel block in a reference image by applying one of the first filter set and the second filter set to the pixel block to be processed based on the filter switching information And a video decoding device.