JP2007129369A - Image reproducing apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reproducing apparatus and an image reproducing method capable of preventing an image quality from being deteriorated by suppressing a filter processing from being doubly executed even when a plurality of decode processes are intermingled. <P>SOLUTION: The image reproducing apparatus 100 includes: a first decoding section 102 for decoding a stream by the H.264; a second decoding section 103 for decoding the stream by the MPEG 2; a filter processing section 104 for applying deblocking filter processing to a decoded moving picture signal; a stream analysis section 105 for extracting information denoting the presence/absence of the deblocking filter processing from the stream; and a filter processing discrimination section 106 for controlling the filter processing section 104 in such a way that the filter processing section executes no filter processing when the deblocking filter processing is set ON, and executes the filter processing when the deblocking filter processing is set OFF. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image reproduction apparatus and method for realizing reproduction with optimum image quality when a plurality of image decoding means are provided.

  In recent years, video and audio signals distributed by television broadcasting over satellites (BS, CS), terrestrial waves, cables, the Internet, etc., are used for hard disks (HDD) and optical disks (DVD-RAM, DVD-R, DVD-RW, DVD + RW, etc.) Digital video recorders for recording on the Internet have become widespread. Currently, MPEG2 is the mainstream of image coding systems in digital video recorders, but H., which is an image coding system with high coding efficiency for the purpose of long-time recording in the future. It is assumed that H.264 / AVC (hereinafter referred to as H.264) is applied. H. Even when H.264 is applied, MPEG2 is used in digital television broadcasting. It is assumed that a digital video recorder capable of recording H.264 and MPEG2 together will be commercialized.

  MPEG2 and H.264 In an image encoding method such as H.264, since the encoding target image is divided into small blocks called macroblocks and the encoding process is executed, block-like noise called block distortion may occur during decoding. is there. In addition, noise due to encoding such as mosquito distortion may occur.

  Therefore, an image reproducing apparatus using MPEG2 may be equipped with a post filter (referred to as a deblocking filter or a deblocking filter, hereinafter referred to as a deblocking filter) for removing block distortion after the decoding process of MPEG2. Many. In addition to the block distortion, a post filter intended to remove mosquito distortion and other noises may be mounted.

  As an example of applying a filter for removing block distortion after image decoding in this way, a digital video signal reproducing apparatus that applies a post filter during special reproduction has been proposed (for example, see Patent Document 1).

  FIG. 2 is a block diagram illustrating an assumed configuration of an image reproduction apparatus in which H.264 and MPEG2 decoding processes are mixed. FIG.

  As shown in FIG. A first decoding unit 102 that performs decoding by H.264, a second decoding unit 103 that performs decoding by MPEG2, and a filter processing unit 104 are provided.

In this image reproducing apparatus, a stream is input to the stream discriminating unit 101, and the stream discriminating unit 101 uses the H.264 stream. The stream determined to be H.264 is output to the first decoding unit 102, and the stream determined to be MPEG2 is output to the second decoding unit 103. The moving image signal decoded by the first decoding unit 102 or the second decoding unit 103 is subjected to filter processing such as a deblocking filter by the filter processing unit 104.
Japanese Patent Application Laid-Open No. 8-26589

  However, H.C. In H.264, a deblocking filter is installed in the decoding system, and a video signal that has already been subjected to the deblocking filter can be output when the stream is decoded. Therefore, H.H. In an image reproducing apparatus in which decoding processing of H.264 and MPEG2 is mixed, When reproducing a stream with the H.264 deblock filter turned on, post-filter processing for MPEG2 is applied, so that the filter processing is executed twice and the image quality deteriorates.

  Therefore, the present invention has been made in view of the above circumstances, and even when a plurality of decoding processes are mixed, the filter process is suppressed from being executed twice, and image quality deterioration is avoided. An object of the present invention is to provide an image reproducing apparatus and an image reproducing method capable of performing the above.

  In order to achieve the above object, an image reproduction apparatus according to the present invention is an image reproduction apparatus that reproduces a moving image by decoding an encoded stream, and includes a filter process for removing noise therein. First decoding means for decoding the stream with one decoding method, and second decoding means for decoding the stream with a second decoding method that does not have a filter process for removing noise therein. Filter processing means for performing filter processing for removing noise on the moving picture decoded by the first decoding means or the second decoding means in accordance with the stream encoding method; By analyzing the stream to be decoded by one decoding means, it is determined whether or not the first decoding means has performed filtering within the first decoding scheme. A stream analyzing means for determining a predetermined unit in the stream, based on a determination result of the stream analyzing means, characterized in that it comprises a filter processing controlling means for controlling the filtering in the filter processing means. Thereby, even when a plurality of decoding processes coexist, it is possible to suppress the filter process from being executed twice and to avoid image quality deterioration.

  The filter processing control means may control the filter processing in the filter processing means in a predetermined unit of the stream based on the determination result of the stream analysis means. Further, the image reproduction device further includes the first reproduction unit for each block obtained by dividing a picture constituting the stream when the stream analysis unit determines that the filtering process is performed within the first decoding scheme. Filter information acquisition means for acquiring filter processing information as to whether or not filtering is performed within the first decoding method from decoding means, wherein the filter processing control means is obtained by the filter information acquisition means. Based on the filter processing information, the filter processing in the filter processing means may be controlled in units of blocks. Thereby, for example, the filtering process can be controlled in units of pictures or slices constituting a stream, or in units of blocks obtained by dividing a picture, and image quality deterioration can be avoided.

  Further, the filter processing means executes a plurality of types of filter processing on the decoded moving image, and the filter processing control means determines whether the filter processing means The filtering process of the same type as the filtering process in the first decoding scheme may be controlled. As a result, by controlling only the type of filter processing that is being executed within the decoding method, it is possible to prevent the filter processing from being executed twice and to avoid image quality degradation. By realizing the filter effect, it is possible to reproduce with optimum image quality.

  Further, the image reproduction device further includes a filter strength determining unit that analyzes the stream and determines a filter strength when the stream analyzing unit determines that the filtering process is performed within the first decoding scheme. The filter processing control means may control the filter processing in the filter processing means according to the filter strength determined by the filter strength determination means. As a result, when filter processing is being executed inside the decoding method, reproduction is performed with the optimum image quality by changing the strength of the filter processing at the subsequent stage of decoding based on the filter strength inside the decoding method. It becomes possible.

  Further, the image reproduction apparatus further includes a quantization information and a filter at the time of decoding by the first decoding unit when the stream analysis unit determines that the filtering process is performed inside the first decoding method. Quantization information analysis means for acquiring at least one of the intensity information, and the filter processing control means according to at least one of the quantization information and the filter intensity information acquired by the quantization information analysis means The filter strength of the filter processing in the filter processing means may be controlled to be changed. As a result, when the filtering process is executed inside the decoding method, the intensity of the filtering process after the decoding is changed in units of blocks based on the information at the time of decoding, so that the reproduction is performed with the optimum image quality. It becomes possible to do.

  Further, the image reproduction device further includes the first reproduction unit for each block obtained by dividing a picture constituting the stream when the stream analysis unit determines that the filtering process is performed within the first decoding scheme. Obtain and obtain from the decoding means at least one of filtering processing information indicating whether or not filtering is performed within the first decoding scheme, quantization information at the time of decoding, and filter strength information at the time of decoding A filtering unit that counts at least one of the filtered processing information, the quantization information, and the filter strength information in a predetermined unit of the stream, and the filtering processing control unit is based on a counting result of the counting unit Then, the filter processing in the filter processing means may be controlled in a predetermined unit of the stream. As a result, when filtering processing is executed within the decoding method, control is performed on a picture-by-picture basis so as not to execute post-decoding filter processing after analyzing information at the time of decoding in block units. Thus, it is possible to efficiently suppress the filter processing and avoid image quality deterioration.

  The present invention can be realized not only as such an image reproducing apparatus, but also as an image reproducing method using steps characteristic of the image reproducing apparatus as a step, or by performing these steps as a computer. It can also be realized as a program to be executed. Needless to say, such a program can be distributed via a recording medium such as a CD-ROM or a transmission medium such as the Internet.

  According to the image reproducing device and the image reproducing method according to the present invention, when the filtering process is executed inside the decoding method, the filtering process is performed by controlling not to execute the filtering process after the decoding. It is possible to suppress double execution and avoid image quality degradation. In addition, by extracting information representing the filter strength from the filtered stream and changing the strength of the post-decoding filter processing, image quality degradation can be avoided and image reproduction with optimal image quality can be realized. Is possible.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an image reproduction apparatus according to Embodiment 1 of the present invention.

  The image playback device 100 is a device for playing back a moving image by decoding with one of two decoding schemes (for example, H.264 and MPEG2), and includes a stream determination unit 101 and a first decoding unit. 102, a second decoding unit 103, a filter processing unit 104, a stream analysis unit 105, and a filter processing determination unit 106. In this embodiment, MPEG2 and H.264 are used. A combination with H.264 will be described as an example. However, as long as one of the decoding methods has a filtering process inside the method, a combination of other decoding methods may be used.

  The stream discriminating unit 101 determines that the input stream to be reproduced is H.264. H.264 or MPEG2 is determined, and H.264 is encoded. The stream determined to be H.264 is output to the first decoding unit 102, and the stream determined to be MPEG2 is output to the second decoding unit 103. Here, the stream discriminating unit 101 analyzes, for example, the header information of the stream or the information of the file system / disk system (for example, BD-ROM standard etc.) to Whether it is H.264 or MPEG2 is determined. When analyzing the header information of the stream, it can be determined by comparing the data for the first several bytes of the header of the video stream. On the other hand, in the file system / disk system, a playlist for setting the reproduction order of moving image data is defined, and this playlist is composed of items such as moving image files. When a video stream is included in an item, since the stream type (MPEG2, H.264, etc.) is defined, the playlist information is acquired from the file system and the stream type is determined. . It is possible to determine whether it is H.264 or MPEG2.

  The first decoding unit 102 converts the input stream to H.264. Decrypt with H.264. The second decoding unit 103 decodes the input stream using MPEG2. The filter processing unit 104 performs deblocking filter processing on the decoded moving image signal. The stream analysis unit 105 receives the H.264 data from the stream determination unit 101. H.264 is analyzed, and information indicating the presence or absence of deblocking filter processing is extracted. H. In H.264, information about whether the deblocking filter processing is ON or OFF can be extracted by a combination of a deblocking_filter_control_present_flag flag included in the picture parameter set in the stream and a disable_deblocking_filter_idc flag included in the slice header. The stream analysis unit 105 outputs an identification signal indicating whether the deblock filter processing is ON or OFF to the filter processing determination unit 106.

  The filter process determination unit 106 is a filter process control unit. When the deblock filter process is ON, the filter process of the filter process unit 104 is not executed. When the deblock filter process is OFF, the filter process is executed. Thus, the filter processing unit 104 is controlled.

FIG. 2 is a block diagram showing a configuration of the first decoding unit 102.
The first decoding unit 102 uses the stream discrimination unit 101 to perform the H.264 decoding. H.264 having a filtering process within the system for a stream determined as H.264. As shown in FIG. 2, an entropy decoding unit 201, an inverse quantization unit 202, an inverse orthogonal transform unit 203, a motion compensation unit 204, an image synthesis unit 205, and a deblocking filter unit 206 are included. I have.

  The entropy decoding unit 201 uses the stream discriminating unit 101 to perform the H.264 decoding. The stream determined to be H.264 is entropy decoded, and a quantized value, a reference index, a motion vector, and the like are output. The motion compensation unit 102 uses the motion vector and the reference index to extract an optimal image region for the predicted image from the decoded image.

  The inverse quantization unit 202 inversely quantizes the quantized value to restore the frequency coefficient, and outputs the frequency coefficient to the inverse orthogonal transform unit 203. The inverse orthogonal transform unit 203 performs inverse frequency transform from the frequency coefficient to the pixel difference value, and outputs the result to the image composition unit 205. The image composition unit 205 adds the pixel difference value and the predicted image output from the motion compensation unit 204 to obtain a decoded image.

  The deblocking filter unit 206 turns off the deblocking filter when the deblocking_filter_control_present_flag flag included in the picture parameter set in the stream and the disable_deblocking_filter_idc flag included in the slice header are (1, 1). When the two flags are other than (1, 1), the deblock filter is switched on / off in units of blocks according to a predetermined condition.

  When switching on / off of the deblocking filter in units of blocks, the deblocking filter unit 206 switches on / off of the deblocking filter according to the following two conditions. As a first condition, the deblocking filter unit 206 turns off the deblocking filter in units of blocks when the pixel value difference at the block boundary is smaller than a predetermined value (α, β). Here, the block is a coding unit divided into 4 × 4 and 8 × 8. The predetermined values (α, β) are calculated from a table as shown in FIG. 3 depending on the QP value (quantization parameter), and the smaller the QP value, the easier it is to turn off. Further, it is possible to change the predetermined value of the table by using two offset values, slice_alpha_c0_offset_div2 and slice_beta_offset_div2, which are set in units of slices (pictures). These two offset values take values of −6 to 6 (default is 0), and the smaller the value is, the more difficult it is to filter.

  Next, as a second condition, the deblocking filter unit 206 turns off the deblocking filter when the Bs value (Boundary Strength) that determines the filter strength is Bs = 0. This Bs value takes a value from 0 to 4, with the Bs value 1 to 4 turning on the deblocking filter, and a larger number applies a stronger filter. In addition, this Bs value is the macro block type (whether it is intra) or not, whether the block is a macro block boundary, whether there is an orthogonal transform coefficient, whether there is a difference in motion vector values, and whether there is a difference in the number of reference pictures It depends on the presence or absence.

  In this way, H.C. In the H.264 decoding process, the deblocking filter unit 206 performs the deblocking filter process in conjunction with the decoding process.

Next, the operation of the image playback device 100 configured as described above will be described.
FIG. 4 is a flowchart showing an operation flow of the image reproducing apparatus.

  A stream to be reproduced is input to the stream determination unit 101. The stream discriminating unit 101 determines that the input stream to be reproduced is H.264. Whether it is encoded by H.264 or MPEG2 is determined (step S101). Here, when it is determined as MPEG2, the stream determination unit 101 outputs the stream determined as MPEG2 to the second decoding unit 103. Then, the second decoding unit 103 decodes the input stream using MPEG2, and outputs the decoded stream to the filter processing unit 104 (step S102). Then, the filter processing unit 104 performs deblocking filter processing on the moving image decoded by the second decoding unit 103 (step S103).

  On the other hand, H. H.264, H.264 is determined. The stream determined to be H.264 is output to the first decoding unit 102 and the stream analysis unit 105. Then, the first decoding unit 102 converts the input stream to H.264. The data is decoded by H.264 and output to the filter processing unit 104 (step S104). In addition, the stream analysis unit 105 performs the H.264 operation. The deblocking_filter_control_present_flag flag included in the picture parameter set in the stream determined to be H.264 and the disable_deblocking_filter_idc flag included in the slice header are extracted (step S105). The stream analysis unit 105 determines whether or not the deblocking filter process is executed by the first decoding unit 102 on the target slice (picture) from the two extracted flags (step S106). Note that a picture can be divided into a plurality of slices, but here it is assumed that one picture is one slice. If the two extracted flags are (1, 1), the stream analysis unit 105 determines that the deblock filter processing is OFF for the slice (No in step S106), and the deblock filter processing is performed. An identification signal indicating OFF is output to the filter processing determination unit 106. When receiving an identification signal indicating that the deblock filter processing is OFF, the filter processing determination unit 106 performs control so that the filter processing in the filter processing unit 104 is executed (step S107). On the other hand, if the two extracted flags are other than (1, 1), the stream analysis unit 105 determines that the deblock filter process is ON for the slice (Yes in step S106), and the deblocking is performed. An identification signal indicating that the filter processing is ON is output to the filter processing determination unit 106. When receiving the identification signal indicating that the deblock filter processing is ON, the filter processing determination unit 106 performs control so that the filter processing in the filter processing unit 104 is not executed (step S108).

  Next, it is determined whether or not processing has been completed for all pictures (step S109). Here, if the processing has been completed for all the pictures (Yes in step S109), the processing ends. On the other hand, if the processing has not been completed for all the pictures (No in step S109), the disable_deblocking_filter_idc flag included in the next slice header is extracted, and the same processing is repeated thereafter (steps S105 to S109). In the second and subsequent flag extraction processing (step S105), for the deblocking_filter_control_present_flag flag included in the picture parameter set, a new deblocking_filter_control_present_flag flag is extracted only when the picture parameter set referred to by the target picture is changed. do it.

  In the present embodiment, the deblock filter process in the filter processing unit 104 is controlled in units of slices (pictures), but the present invention is not limited to this. For example, filter processing information indicating whether or not deblocking filter processing is performed in the first decoding unit 102 is acquired from the first decoding unit 102 in units of blocks. Then, the filter processing determination unit 106 does not execute the filter processing of the filter processing unit 104 and turns off the deblocking filter processing when the filtering processing information indicates that the deblocking filtering processing is ON for each block. In the case shown, the filter processing unit 104 may be controlled to execute the filter processing.

  As described above, it is determined whether or not the stream or the stream storing data is a stream that has been filtered within the decoding method. If the filtering process is being executed within the decoding method, the decoding is performed. By performing control so that the subsequent filtering process is not performed, it is possible to suppress the filtering process from being performed twice and to avoid image quality deterioration.

(Embodiment 2)
In the first embodiment, only the deblocking filter process is performed on the moving image signal decoded by the filter processing unit 104. In the present embodiment, a case where a plurality of filter processes are performed will be described.

  FIG. 5 is a block diagram showing a configuration of an image reproduction apparatus according to Embodiment 2 of the present invention. Note that portions similar to those in the configuration of the image reproduction device according to Embodiment 1 are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 5, the image reproduction device 300 according to the present embodiment includes a filter processing selection unit 301 instead of the filter processing determination unit 106 according to the first embodiment. Further, the operation of the filter processing unit 302 is different.

  The filter processing unit 302 performs, for example, a filter process for removing mosquito distortion and other noises in addition to a plurality of filter processes, that is, a deblocking filter process, on the decoded moving image signal.

  The filter process selection unit 301 is a filter process control unit. When the deblock filter process is ON, only the deblock filter process of the filter process unit 302 is not selected and executed, and the filter process having other effects is performed. Controls the filter processing unit 302 to execute. In addition, when the deblocking filter process is OFF, the filter processing selection unit 301 controls the filter processing unit 302 to execute all the filtering processes including the deblocking filter.

  As described above, it is determined whether or not the stream or the stream storing data is a stream that has been filtered within the decoding method. If the filtering process is being executed within the decoding method, the decoding is performed. By controlling only the deblocking filter when controlling so as not to execute the subsequent filtering process, it is possible to suppress the deblocking filter process from being executed twice, and to avoid degradation in image quality. By realizing the filter effect, it is possible to reproduce with optimum image quality.

(Embodiment 3)
In the first embodiment, control is performed so that the deblocking filter process in the filter processing unit 104 is executed or not executed. In this embodiment, a case where the strength of the deblocking filter process is changed will be described.

  FIG. 6 is a block diagram showing a configuration of an image reproduction apparatus according to Embodiment 3 of the present invention. Note that portions similar to those in the configuration of the image reproduction device according to Embodiment 1 are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 6, the image reproduction device 400 according to the present embodiment includes a filter strength determination unit 401 and a filter strength change unit 402 instead of the filter processing determination unit 106 according to the first embodiment. Also, the operations of the filter processing unit 403 and the stream analysis unit 404 are different.

  The filter processing unit 403 changes the intensity of deblocking filter processing applied to the decoded moving image signal and executes it. Similarly to the first embodiment, the stream analysis unit 404 extracts information indicating the presence or absence of deblocking filter processing and outputs an identification signal, and extracts an offset value related to the filter strength included in the slice header of the stream. Notify the strength determination unit 401. The identification signal is output to the filter strength determination unit 401.

  The filter strength determination unit 401 determines the strength of the deblocking filter processing based on the offset value notified from the stream analysis unit 404 and outputs a filter strength signal indicating the strength of the deblocking filter processing to the filter strength changing unit 402. To do. For example, the filter strength determination unit 401 determines the strength level in five steps according to the offset values −6 to −4, −3 to −2, −1 to 0, 1 to 2, 3 to 4, and 5 to 6. To do.

  The filter strength changing unit 402 is a filter processing control unit, and controls the filter strength of the filter processing unit 403 to be changed and executed in units of slices based on the filter strength signal. For example, when the deblocking filter strength is high, control such as reducing the filter strength of the filter processing unit 403 is executed.

Next, the operation of the image reproduction device 400 configured as described above will be described.
FIG. 7 is a flowchart showing an operation flow of the image reproducing apparatus according to the third embodiment. Note that the stream discrimination processing (step S101) by the stream discrimination unit 101 to the execution processing (step S107) of the filter processing by the filter processing unit 104 are the same as those in the first embodiment, and thus description thereof is omitted.

  If the stream analysis unit 404 determines that the deblocking filter process is ON (Yes in step S106), the stream analysis unit 404 extracts an offset value related to the filter strength included in the slice header of the stream (step S201). Then, the stream analysis unit 404 outputs an identification signal indicating that the deblocking filter process is ON and an offset value to the filter strength determination unit 401. When receiving an identification signal and an offset value indicating that the deblocking filter process is ON, the filter strength determining unit 401 determines the strength of the deblocking filter process based on the offset value, and the deblocking filter process A filter strength signal indicating the strength of the output is output to the filter strength changing unit 402 (step S202). Based on the filter strength signal, the filter strength changing unit 402 performs control so as to change and execute the filter strength of the filter processing unit 403 for the target slice (picture) (step S203). For example, when the deblocking filter strength is high, control such as reducing the filter strength of the filter processing unit 403 is executed. The subsequent processing (step S109) is the same as in the first embodiment.

  In the present embodiment, the strength of the deblocking filter process is determined based on the offset value, and based on the result, control is performed so that the filter strength of the filter processing unit 403 is changed and executed for each slice. However, if the offset value is equal to or greater than the predetermined threshold value, the filter processing unit 403 may be controlled not to execute the filter processing.

  As described above, it is determined whether or not the stream or the stream storing data is a stream that has been filtered within the decoding method. If the filtering process is being executed within the decoding method, the decoding is performed. When performing control so that the subsequent filtering process is not performed, the information on the filter strength on the stream is analyzed, and the strength of the filtering processing in the subsequent decoding process is changed based on this filter strength, so that the optimum image quality can be obtained. Can be played.

(Embodiment 4)
In the third embodiment, the strength of the deblocking filter process in the filter processing unit 403 is changed in units of slices, but in this embodiment, a case where the strength of the deblocking filter process is changed in units of blocks will be described.

  FIG. 8 is a block diagram showing a configuration of an image reproduction apparatus according to Embodiment 4 of the present invention. Note that portions similar to those in the configuration of the image reproduction device according to Embodiment 3 are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 8, the image reproduction device 500 according to the present embodiment includes a quantization information analysis unit 501 instead of the filter strength determination unit 401 according to the third embodiment. Further, the operation of the filter strength changing unit 502 is different. Further, the stream analysis unit 404 outputs an offset value related to the identification signal and the filter strength to the quantization information analysis unit 501.

  The quantization information analysis unit 501 obtains an average value and Bs value of QP values (quantization parameters) of two blocks to be subjected to deblocking filter processing based on the decoding result from the first decoding unit 102. To do. For example, assuming that the strength level of the deblocking filter of the first decoding unit 102 is 0 to 20, the quantization information analysis unit 501 is based on the filter strength signal, the average value of the QP values, and the Bs value. The intensity level is calculated from 0 to 20, and the calculated intensity level is notified to the filter intensity changing unit 502.

  Based on the strength level notified from the quantization information analysis unit 501, the filter strength changing unit 502 determines the filter strength of the filter processing unit 403 in units of blocks such as the straight line 11 or the straight line 12 illustrated in FIG. Then, control is performed so that the filter processing is executed with the determined filter strength. Here, in the example shown in FIG. 9, it is assumed that the filter strength level of the filter processing unit 403 is 0 to 20 (in this case, the filter coefficient value is 20 patterns).

Next, the operation of the image reproduction device 500 configured as described above will be described.
FIG. 10 is a flowchart showing an operation flow of the image reproduction apparatus according to the fourth embodiment. Note that the stream discrimination processing (step S101) by the stream discrimination unit 101 to the execution processing (step S107) of the filter processing by the filter processing unit 104 are the same as those in the first embodiment, and thus description thereof is omitted.

  If the stream analysis unit 404 determines that the deblocking filter process is ON (Yes in step S106), the stream analysis unit 404 extracts an offset value related to the filter strength included in the slice header of the stream (step S201). Then, the stream analysis unit 404 outputs an identification signal indicating that the deblocking filter process is ON and an offset value to the quantization information analysis unit 501. When the quantization information analysis unit 501 receives the identification signal and the offset value indicating that the deblocking filter process is ON, the two blocks to be subjected to the deblocking filter process from the first decoding unit 102 The average value of the QP values and the Bs value are acquired (step S301). Next, the quantization information analysis unit 501 calculates how much the intensity level is from 0 to 20 based on the filter intensity signal, the average value of the QP values, and the Bs value, and calculates the calculated intensity level. The filter strength change unit 502 is notified as a filter strength signal (step S302). Then, the filter strength changing unit 502 determines the filter strength of the filter processing unit 403 in units of blocks based on the strength level notified from the quantization information analyzing unit 501, and executes the filter processing with the determined filter strength. (Step S303).

  Next, it is determined whether or not processing has been completed for all blocks of the target picture (step S304). Here, if the processing has not been completed for all the blocks (No in step S304), the average value of the QP values of the two blocks to be subjected to the next deblocking filter processing and the Bs value are acquired. The same processing as above is repeated (steps S301 to S304). On the other hand, if the processing has been completed for all the blocks (Yes in step S304), it is determined whether or not the processing has been completed for all the pictures (step S109). The subsequent processing is the same as in the first embodiment.

  In the present embodiment, the quantization information analysis unit 501 calculates the intensity level based on the filter intensity signal, the average value of the QP values, and the Bs value, and sends the calculated intensity level to the filter intensity changing unit 502. This is notified, but is not limited to this. For example, the quantization information analysis unit 501 notifies the filter strength changing unit 502 of the average value or Bs value of the acquired QP values without calculating the strength level. Then, based on the average value or Bs value of the QP values notified from the quantization information analysis unit 501, the filter strength changing unit 502, for example, the straight line 13, the straight line 14, and the straight line illustrated in FIGS. Alternatively, the filter strength of the filter processing unit 403 may be determined in units of blocks as indicated by 15 or the straight line 16, and the filter processing may be executed with the determined filter strength. In this case, the horizontal axis shown in FIG. 9 is an average value of QP values or a Bs value.

  In the present embodiment, the quantization information analysis unit 501 calculates the intensity level in units of blocks based on the filter intensity signal, the average value of the QP values, and the Bs value. However, the present invention is not limited to this. is not. For example, the quantization information analysis unit 501 may obtain an average value of the acquired QP value and Bs value in the picture, and calculate an intensity level in the picture based on the average value. In this case, the filter strength changing unit 502 determines the filter strength of the filter processing unit 403 for each picture and performs control so that the filter processing is executed with the determined filter strength.

  As described above, it is determined whether or not the stream or the stream storing data is a stream that has been filtered within the decoding method. If the filtering process is being executed within the decoding method, the decoding is performed. When performing control so that the subsequent filtering process is not performed, it is possible to reproduce the image with the optimum image quality by analyzing the information at the time of decoding and changing the strength of the filtering process after the decoding in block units. It becomes.

(Embodiment 5)
In the first embodiment, the deblock filter processing in the filter processing unit 104 is controlled based on two flags, but in the present embodiment, a case where control is performed using other conditions will be described.

  FIG. 11 is a block diagram showing a configuration of an image reproduction apparatus according to Embodiment 5 of the present invention. Note that portions similar to those in the configuration of the image reproduction device according to Embodiment 1 are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 11, the image reproduction device 600 of this embodiment includes a totaling unit 601 in addition to the configuration of the first embodiment. The stream analysis unit 105 outputs an identification signal indicating whether the deblocking filter process is ON or OFF to the counting unit 601.

  When the identification signal indicates that the deblocking filter process is ON, the totaling unit 601 is deblocking filtered within the first decoding unit 102 from the first decoding unit 102 in units of blocks. Get negative filtering information. Further, the counting unit 601 counts the number of blocks that have been deblocked using the filter processing information for each picture, and the deblocking filter process is performed on the picture if the count is equal to or greater than a predetermined threshold. Is determined.

  When it is determined that the deblocking filter process is being performed, the filter processing determining unit 106 does not execute the filtering process of the filter processing unit 104 and when it is determined that the deblocking filter process is not being performed. Then, the filter processing unit 104 is controlled to execute the filter processing.

  In the present embodiment, the aggregation unit 601 obtains the filter processing information indicating whether or not the deblocking filter processing is performed inside the first decoding unit 102 from the first decoding unit 102. It is not limited to this. For example, the totaling unit 601 acquires the Bs value from the first decoding unit 102 in units of blocks, counts the number of blocks having a Bs value greater than 0 for each picture, and if the value is equal to or greater than a predetermined threshold, the picture It may be determined that the deblocking filter process is being performed. Further, the totaling unit 601 obtains a QP value for each block from the first decoding unit 102, calculates the average value for each picture by adding the QP value, and the average value is equal to or greater than a predetermined threshold value. In addition, it may be determined that the number of blocks on which the deblocking filter processing is performed is large, and it is determined that the deblocking filter processing is performed on the picture.

  Further, in this embodiment, when the identification signal indicates that the stream analysis unit 105 is provided and the deblock filter processing is ON, the totaling unit 601 acquires the filter processing information in units of blocks. It is not limited to this. For example, the stream analysis unit 105 is not provided, and the aggregation unit 601 may always acquire the filter processing information in units of blocks.

  As described above, it is determined whether or not the stream or the stream storing the stream is a stream that has been filtered within the decoding method. By analyzing the information at the time of decoding, and controlling in units of pictures so as not to execute the filtering process after decoding, it is possible to efficiently suppress the filtering process and avoid the deterioration of the image quality. .

  Each of the functional blocks in the block diagrams shown in FIGS. 1, 5, 6, 8, and 11 is typically realized as an LSI that is an integrated circuit. This LSI may be made into one chip or a plurality of chips. (For example, the functional blocks other than the memory may be integrated into one chip.) Although the LSI is used here, it may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of the LSI or a reconfigurable processor that can reconfigure the connection and setting of the circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology can be applied.

  In addition, among the functional blocks, only the unit for storing data may be configured separately without being integrated into one chip.

  The image display device and the image display method according to the present invention can be applied to, for example, a personal computer, an HDD recorder, a DVD recorder, and the like, and are used for viewing with optimum image quality when reproducing a stream encoded by a plurality of systems. Useful as.

It is a block diagram which shows the structure of the image reproduction apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of a 1st decoding part. It is a figure which shows the table for calculating the threshold value ((alpha), (beta)) at the time of determining the intensity | strength of a deblocking filter. 3 is a flowchart showing a flow of operations of the image reproduction device according to the first embodiment. It is a block diagram which shows the structure of the image reproduction apparatus which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the image reproduction apparatus which concerns on Embodiment 3 of this invention. 10 is a flowchart showing an operation flow of the image reproduction apparatus according to the third embodiment. It is a block diagram which shows the structure of the image reproduction apparatus which concerns on Embodiment 4 of this invention. (A) The figure which shows the relationship between the intensity level of the deblocking filter of a 1st decoding part, and the filter intensity level of a filter process part, (b) The relationship between the average value of QP value and the filter intensity level of a filter process part (C) is a diagram showing the relationship between the Bs value and the filter strength level of the filter processing unit. 14 is a flowchart showing a flow of operations of the image reproduction device according to the fourth embodiment. It is a block diagram which shows the structure of the image reproduction apparatus which concerns on Embodiment 5 of this invention. H. 2 is a block diagram illustrating an assumed configuration of an image reproduction apparatus in which H.264 and MPEG2 decoding processes are mixed. FIG.

Explanation of symbols

100, 300, 400, 500, 600 Image reproduction apparatus 101 Stream determination unit 102 First decoding unit 103 Second decoding unit 104, 302, 403 Filter processing unit 105, 404 Stream analysis unit 106 Filter processing determination unit 201 Entropy decoding unit 202 Inverse quantization unit 203 Inverse orthogonal transform unit 204 Motion compensation unit 205 Image synthesis unit 206 Deblock filter unit 301 Filter processing selection unit 401 Filter strength determination unit 402, 502 Filter strength change unit 501 Quantization information analysis unit 601 Aggregation Department

Claims (16)

An image reproduction apparatus for reproducing a moving image by decoding an encoded stream,
First decoding means for decoding the stream by a first decoding method having a filter process for removing noise therein;
Second decoding means for decoding the stream by a second decoding method that does not have a filtering process for removing noise therein;
Filter processing means for performing filter processing for removing noise on the moving picture decoded by the first decoding means or the second decoding means in accordance with the stream encoding method;
By analyzing the stream decoded by the first decoding means, it is determined in a predetermined unit of the stream whether or not the first decoding means is filtering in the first decoding scheme. Stream analysis means to
An image reproduction apparatus comprising: a filter processing control unit that controls filter processing in the filter processing unit based on a determination result of the stream analysis unit. The image reproduction device according to claim 1, wherein the filter processing control unit controls the filter processing in the filter processing unit in a predetermined unit of the stream based on a determination result of the stream analysis unit. The image playback device further includes:
When it is determined by the stream analysis means that the filtering process is performed inside the first decoding method, the first decoding method is used by the first decoding means in units of blocks obtained by dividing the pictures constituting the stream. Filter information acquisition means for acquiring filter processing information as to whether or not it is internally filtered,
The image reproduction according to claim 1, wherein the filter processing control unit controls the filter processing in the filter processing unit in units of blocks based on the filter processing information acquired by the filter information acquisition unit. apparatus. The filter processing control unit controls the stream analysis unit so as not to execute the filter processing in the filter processing unit when it is determined by the stream analysis unit that filtering is performed within the first decoding scheme. 2. The image reproduction device according to claim 1, wherein when it is determined that the filtering process is not performed in the first decoding method, the filtering process in the filter processing unit is controlled. The first decoding means has a filter process for removing block noise as the filter process in the first decoding method,
The image reproduction device according to claim 1, wherein the filter processing unit performs a filter process for removing block noise on the decoded moving image. The filter processing means performs a plurality of types of filter processing on the decoded moving image,
The filter processing control means controls, based on the determination result of the stream analysis means, the same kind of filter processing as the type being filtered in the first decoding method in the filter processing means. The image reproducing apparatus according to claim 1. The image playback device further includes:
When it is determined by the stream analysis means that the filter processing is performed inside the first decoding method, the stream analysis means comprises filter strength determination means for analyzing the stream and determining filter strength,
The image reproduction apparatus according to claim 1, wherein the filter processing control unit controls the filter processing in the filter processing unit in accordance with the filter strength determined by the filter strength determination unit. The filter processing control means controls not to execute the filter processing in the filter processing means when the filter strength determined by the filter strength determination means is equal to or greater than a predetermined threshold, and the filter strength is equal to or greater than a predetermined threshold. If not, control is performed so as to execute filtering processing in the filtering processing means. The image according to claim 7, wherein the filter processing control unit performs control so as to change a filter strength of the filter processing in the filter processing unit in accordance with the filter strength determined by the filter strength determination unit. Playback device. The filter processing control means controls to change the filter strength of the filter processing in the filter processing means so as to be inversely proportional to the filter strength determined by the filter strength determination means. Image playback device. The image playback device further includes:
A quantum that obtains at least one of quantization information and filter strength information at the time of decoding from the first decoding means when it is determined by the stream analysis means that filtering is performed within the first decoding scheme; Equipped with chemical information analysis means,
The filter processing control means controls to change the filter strength of the filter processing in the filter processing means according to at least one of the quantization information and the filter strength information acquired by the quantization information analysis means. The image reproducing apparatus according to claim 1, wherein: The filter processing control means is a filter in the filter processing means according to at least one of the quantization information and the filter strength information in units of pictures or slices constituting the stream, or in units of blocks obtained by dividing the picture. The image reproduction device according to claim 11, wherein the control is performed so as to change a filter strength of the processing. The image playback device further includes:
When it is determined by the stream analysis means that the filtering process is performed inside the first decoding scheme, the first decoding means performs the first decoding by the block unit obtained by dividing the picture constituting the stream. At least one of filter processing information indicating whether or not filtering is performed within the scheme, quantization information at the time of decoding, and filter strength information at the time of decoding is acquired, and the acquired filter processing information and the quantization information And tally means for tallying at least one of the filter strength information in a predetermined unit of the stream,
The image reproduction apparatus according to claim 1, wherein the filter processing control unit controls the filter processing in the filter processing unit in a predetermined unit of the stream based on a totaling result of the totaling unit. An image reproduction method for reproducing a moving image by decoding an encoded stream,
A first decoding step of decoding the stream by a first decoding method having a filter process for removing noise therein;
A second decoding step of decoding the stream by a second decoding method that does not have a filtering process for removing noise therein;
A filter processing step for executing a filter process for removing noise on the moving image decoded in the first decoding step or the second decoding step according to the encoding method of the stream;
By analyzing the stream decoded in the first decoding step, it is determined in a predetermined unit of the stream whether or not the filtering process is performed in the first decoding method in the first decoding step. Stream analysis step to perform,
An image reproduction method comprising: a filter processing control step for controlling the filter processing in the filter processing step based on the determination result in the stream analysis step. A program for decoding an encoded stream and reproducing a moving image,
A first decoding step of decoding the stream by a first decoding method having a filter process for removing noise therein;
A second decoding step of decoding the stream by a second decoding method that does not have a filtering process for removing noise therein;
A filter processing step for executing a filter process for removing noise on the moving image decoded in the first decoding step or the second decoding step according to the encoding method of the stream;
By analyzing the stream decoded in the first decoding step, it is determined in a predetermined unit of the stream whether or not the filtering process is performed in the first decoding method in the first decoding step. Stream analysis step to perform,
A program that causes a computer to execute a filter processing control step that controls filter processing in the filter processing step based on a determination result in the stream analysis step. An integrated circuit for decoding a coded stream and reproducing a moving image,
First decoding means for decoding the stream by a first decoding method having a filter process for removing noise therein;
Second decoding means for decoding the stream by a second decoding method that does not have a filtering process for removing noise therein;
Filter processing means for performing filter processing for removing noise on the moving picture decoded by the first decoding means or the second decoding means in accordance with the stream encoding method;
By analyzing the stream decoded by the first decoding means, it is determined in a predetermined unit of the stream whether or not the first decoding means is filtering in the first decoding scheme. Stream analysis means to
An integrated circuit comprising: filter processing control means for controlling filter processing in the filter processing means based on a determination result of the stream analysis means.

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