JP2013123192A - Moving image encoder, moving image encoding system and moving image encoding program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Wyner-Ziv frame encoder which can prevent encoding efficiency from being deteriorated when a difference between an original signal and side information estimated on the encoding side is small.SOLUTION: A Wyner-Ziv frame encoder includes: a Slepian-Wolf encoding section which Slepian-Wolf-encodes inputted data; and a quantization section which performs processing that generates data encoded in the Slepian-Wolf encoding section from an encoding object frame image and that includes quantization. The encoder also includes: a side information generation section which generates update candidate information from a reference frame image; and a quantization data update control section which updates data of the quantization section to update candidate information when the data generated in the quantization section largely differs from the update candidate information.

Description

  The present invention relates to a moving image coding apparatus, system, and program, and can be applied to, for example, one using a distributed video coding method (hereinafter referred to as a DVC method).

  In recent years, a new encoding method called the DVC method as described in Non-Patent Document 1 has attracted attention.

  In the DVC method, several frames of images (hereinafter referred to as key frames or key frame images) that become keys every few frames (not necessarily at regular intervals) are encoded within a frame. Encoding is applied (an inter-frame encoding method may be applied to some key frames), while other (or all) frames (Wyner-Ziv frames (non-key frames)) For ()), only the error correction code of the prediction error signal in the time direction is encoded and transmitted.

  Today's DVC scheme is a new compression scheme based on two key information theories, the Slepian-Wolf theorem and the Wyner-Ziv theorem. In the DVC method, a Slepian-Wolf encoding process is performed on an original image to be encoded by a Wyner-Ziv frame encoder (an image of a Wyner-Ziv frame: hereinafter referred to as a WZ frame or a WZ frame image). This is a new encoding method in which Slepian-Wolf decoding is performed based on encoded data and a predicted image of an original image on the Wyner-Ziv frame encoder side obtained on the Wyner-Ziv frame decoder side.

  The DVC method as described in Non-Patent Document 1 has no characteristics in encoding and decoding of key frames. Therefore, referring to FIG. 1 of Non-Patent Document 1, encoding and decoding of WZ frames will be described below. I will explain from the aspect. FIG. 7 is a drawing directly showing FIG. 1 of Non-Patent Document 1.

The Wyner-Ziv frame encoder converts (DCT) a WZ frame to be encoded into a transform coefficient domain (frequency domain), and then performs quantization (2 ^MK level Quantizer) for each component in the frequency domain, The converted value (q _k ) is converted into a bit string code, and the information of each bit is subjected to, for example, Slepian-Wolf encoding (Turbo Encoder) for each information (Extract bit-planes) collected for one frame, Of the results, only the parity bits are temporarily stored (Buffer), and the information bits are discarded (not clearly shown in FIG. 1 of Non-Patent Document 1).

  In the Wyner-Ziv frame decoder, a predicted image is generated (Interpolation / Extrapolation), the predicted image is converted into a transform coefficient domain (DCT), and for each component in the frequency domain, a Slepian-Wolf is used as side information (Side Information). It inputs into a decoding part (Turbo Decoder).

  The Slepian-Wolf decoding unit makes a transmission request (Request bits) to a part of the temporarily stored parity bits to the Wyner-Ziv frame encoder. Slepian-Wolf decoding is performed from the received parity bit and the side information described above. If sufficient decoding cannot be performed, the Wyner-Ziv frame encoder side again requests a part of the parity bit to be transmitted (Request bits), and from the received parity bit and the above side information, the Slepian- Wolf decoding is performed. This process is continued until sufficient decoding can be performed.

  Thereafter, a transform coefficient is reconstructed from the decoded value of the Slepian-Wolf decoding and the side information, and a decoded image is obtained by performing inverse transform (IDCT).

  FIG. 7 described above shows the configuration of the DVC system represented by the description of Non-Patent Document 1. Non-Patent Document 1 introduces a method of encoding information (DCT coefficients) after DCT conversion is performed on a predetermined block with the number of vertical and horizontal pixels (transform-domain; conversion coefficient region). The encoding target is not limited to this, and there is also a coding target that does not perform DCT conversion but performs encoding at the pixel-domain information stage.

  In the DVC method, for Wyner-Ziv frames (hereinafter abbreviated as WZ frames), information (parity bits or syndrome bits) for error correction is transmitted from the moving image encoding device to the moving image decoding device, In the moving image decoding apparatus, by performing error correction processing from the information obtained by converting the predicted image of the WZ frame predicted from the key frame so that the error correction processing can be performed and the information for executing the received error correction, The information of the transform coefficient region or the pixel region that the moving image encoding device is to transmit is decoded.

  The technique described in Non-Patent Document 1 is that the video encoding device performs feedback control that gradually transmits information for performing error correction every time there is a request from the video decoding device. . Conventionally, a moving picture decoding apparatus determines the amount of information (code amount) for performing error correction required by the moving picture decoding apparatus without requiring a moving picture decoding apparatus, and according to the amount. A DVC method for transmitting information for performing error correction has also been proposed. The DVC method that does not perform such feedback control is described in Non-Patent Document 2, for example.

  FIG. 8 shows a configuration of a conventional moving picture encoding apparatus according to the DVC method that does not perform feedback control. For example, Non-Patent Document 2 describes a DVC system that does not perform feedback control. FIG. 8 illustrates the WZ frame divided into blocks so that it can be applied when encoding in the transform coefficient region or in the pixel region. In the following, it is assumed that encoding is performed in the pixel region. Processing of the Wyner-Ziv frame encoding unit 102 will be described.

  The side information generation unit 103 of the Wyner-Ziv frame encoding unit 102 inputs encoded data of at least one key frame before and after the WZ frame, and locally decodes the encoded data of the key frame and returns the key frame to the key frame. Later, a predicted image of the WZ frame is generated, and a plurality of the predicted images of the generated WZ frame are collected and quantized in the pixel region, and the quantized value is converted into a bit string code. Divide bits into collected bitplanes. On the other hand, the quantization unit 104 to which the WZ frame image is input collects a plurality of images and quantizes the WZ frame image in the pixel region, converts the quantized value into a bit string code, and then converts the bit at each bit position. Divide into collected bit planes. The code amount control unit 105 calculates a transmission code amount from the output of the side information generation unit 103 and the output of the quantization unit 104, and the Slepian-Wolf encoding unit 106 receives the bit plane input from the quantization unit 104. Each data is subjected to Slepian-Wolf encoding such as Turbo code or LDPC code, and an error correction code (parity bit or syndrome bit) corresponding to the code amount calculated by the transmission code amount control unit 105 is transmitted to the decoding side. To do.

  The more similar the WZ frame image and its predicted image, the smaller the transmission code amount. The transmission code amount control unit 105 determines the degree of similarity between the WZ frame image and the predicted image using a quantization value.

  The configuration of the Wyner-Ziv decoding unit corresponding to the Wyner-Ziv frame encoding unit 102 in FIG. 8 is almost the same as the configuration shown in FIG. However, the only difference is that the Slepian-Wolf decoding unit does not request an error correction code from the encoding side.

  FIG. 9 shows a conventional flow of encoding and decoding in the pixel area. FIG. 9 focuses on a certain pixel in order to make it easier to understand a problem to be described later.

  As shown in FIG. 9A, consider a case where the original signal (□) of a certain pixel is 130 and the side information (◯) estimated on the encoding side is 120. For simplicity, the number of bit planes is 1 (quantization size = 128). As shown in FIG. 9B1, the original signal (□) 130 is quantized to a quantized value “1”, and the side information (◯) is quantized to a quantized value “0”. Since the quantized values are different from each other, a parity bit is transmitted when the Slepian-Wolf code is a Turbo code, and a syndrome bit is transmitted when the Lepian-Wolf code is LDPC encoded.

  On the other hand, on the decoding side, error correction decoding is performed by Slepian-Wolf decoding, and the quantized value “1” is decoded. If the quantization value “1” is the same as the side information on the decoding side, the side information value becomes the final decoded value (pixel value) by image reconstruction. In this case, the side information 120 is quantized. Since the quantized value is different from the quantized value “0”, the pixel value (in this case, any value from 128 to 255) that can represent the quantized value “1” is decoded. For example, FIG. 9B2 shows the case where the median value “192” is adopted as the final decoded value (pixel value).

Anne Aaron, Shantan Rane, Eric Setton, and Bern Grid: Transform-domain Wyner-Ziv Code for Video. In: Proc, SPIE Visual Communications and Image Processing, San Jose, CA (2004) C. Brites, F.M. Pereira, “Encoder Rate Control for Transform Domain Wyner-Ziv Video Coding,” ICIP 2007, USA, September, 2007

  However, in the example shown in FIG. 9 in which the original signal (□) is 130 and the side information (O) estimated on the encoding side is 120, the original signal and the side information are different quantization values. Side information having a small difference from the original signal (here, 10) cannot be used, and a decoded value of 192 is obtained. The difference between the decoded value and the original signal is 62, and the PSNR (Peak Signal-to-Noise Ratio) is remarkably deteriorated.

  That is, in the related art, there is a problem that although the difference between the original signal and the side information estimated on the encoding side is small, the PSNR deteriorates (encoding efficiency deteriorates).

  Therefore, there is a demand for a moving image encoding apparatus, system, and program that can prevent deterioration in encoding efficiency when the difference between the original signal and side information estimated on the encoding side is small.

  The first aspect of the present invention is a moving image encoding device including a quantization unit and a Slepian-Wolf encoding unit, (1) a side information generation unit that generates update candidate information from a reference frame image, and (2) the above When the data of the quantization unit generated for encoding by the Slepian-Wolf encoding unit is greatly different from the update candidate information, the data of the quantization unit is updated to the update candidate information. And a quantized data update control unit.

  A second aspect of the present invention is a key frame encoding device that encodes a key frame separated from a frame sequence, and a quantization unit and a Slepian-Wolf encoding unit that encode a non-key frame separated from the frame sequence. In the moving picture coding apparatus having the Wyner-Ziv frame coding apparatus, the moving picture coding apparatus according to the first aspect of the present invention is applied as the Wyner-Ziv frame coding apparatus.

  A moving picture coding system according to a third aspect of the present invention includes the moving picture coding apparatus according to the second aspect of the present invention and a moving picture decoding apparatus that decodes key frames and non-key frames.

  The moving image encoding program of the fourth aspect of the present invention includes a computer, (1) a Slepian-Wolf encoding unit that encodes input data into a Slepian-Wolf, and (2) the above-described Slepian from an encoding target frame image. A quantization unit that generates data to be encoded by the Wolf encoding unit and that performs processing including quantization; (3) a side information generation unit that generates update candidate information from a reference frame image; 4) When the data of the quantization unit generated for encoding by the Slepian-Wolf encoding unit is greatly different from the update candidate information, the data of the quantization unit is changed to the update candidate information. It is made to function as a quantized data update control unit for updating to.

  According to the present invention, it is possible to prevent the encoding efficiency from deteriorating when the difference between the original signal and the side information estimated on the encoding side is small.

It is a block diagram which shows the structure of the moving image encoding system which concerns on embodiment. It is a block diagram which shows the detailed structure of the quantization data update control part in the moving image encoder of embodiment. It is a flowchart which shows operation | movement of the moving image encoder of embodiment. It is a flowchart which shows the detail of operation | movement of the quantization data update control part in the moving image encoder of embodiment. In the moving image encoding device of an embodiment, it is explanatory drawing of the update control example (the 1) of quantization data in case the difference of an original signal and the side information estimated on the encoding side is small. In the moving image coding apparatus of embodiment, it is explanatory drawing of the update control example (the 2) of quantization data in case the difference of an original signal and the side information estimated on the encoding side is small. It is drawing which showed FIG. 1 of the nonpatent literature 1 as it was. It is a block diagram which shows the structure of the moving image encoding apparatus using the conventional estimated image. In the conventional moving image encoder, it is explanatory drawing of the subject which arises when the difference of an original signal and the side information estimated on the encoding side is small.

(A) Main Embodiments Hereinafter, an embodiment of a moving image encoding apparatus, system, and program according to the present invention will be described in detail with reference to the drawings. The moving picture coding system according to this embodiment is the DVC system described above.

(A-1) Configuration of Embodiment FIG. 1 is a block diagram showing a configuration of a video encoding system having a video encoding device and a video decoding device of this embodiment. The moving image encoding device 150 and the moving image decoding device 200 according to the embodiment may be constructed by connecting various circuits in hardware, and a general-purpose device having a CPU, a ROM, a RAM, and the like is a moving image. It may be constructed so as to realize a function as a moving image encoding device or a moving image decoding device by executing an encoding program or a moving image decoding program. Regardless of which construction method is applied, the functional configurations of the video encoding device 100 and the video decoding device 200 can be represented in FIG.

  In FIG. 1, the moving image encoding device 150 includes a key frame encoding unit 151 and a Wyner-Ziv frame encoding unit 152. The Wyner-Ziv frame encoding unit 152 alone is a kind of moving image encoding device.

  The key frame encoding unit 151 encodes the key frame image with a predetermined encoding method such as MPEG or JPEG, and transmits the encoded data to the decoding side.

  As described above, in the DVC framework, there are a method of performing processing in the pixel region and a method of performing processing in the transform coefficient region by conversion such as DCT when encoding an input WZ frame. In this embodiment, a method of performing processing in the pixel region is applied.

  The Wyner-Ziv frame encoding unit 152 includes a side information generation unit 153, a quantization unit 154, a quantized data update control unit 155, an encoding control unit 156, and a Slepian-Wolf encoding unit 157.

  The side information generation unit 153 receives the encoded data of the key frame before the WZ frame, after the WZ frame, or before and after the WZ frame, and generates a predicted image of the WZ frame. Which of the key frames before the WZ frame, after the WZ frame, or before and after the WZ frame is applied is determined in advance. Further, the side information generation unit 153 generates a prediction image of the WZ frame after locally decoding the encoded data of the key frame and returning it to the key frame, and collects a plurality of pixels of the generated prediction image of the WZ frame. Then, the quantized value is converted into a bit string code (binarized), and then divided into bit planes in which bits are collected for each bit of the same digit.

  The quantizing unit 154 quantizes the WZ frame image (image data inserted between the key frames), converts the quantized value into a bit string code (binarization), and then converts the quantized value for each bit position. The bits are divided into bit planes.

  The quantized data update control unit 155 determines whether or not to update the quantized data obtained by the quantizing unit 154 based on the WZ frame, the output of the quantizing unit 154, and the output of the side information generating unit 153, and updates If so, the quantized data is updated.

  The code amount control unit 156 calculates a transmission code amount from the output of the side information generation unit 153 and the output of the quantized data update control unit 155.

  The Slepian-Wolf encoding unit 157 performs Sleian-Wolf encoding such as Turbo code or LDPC code on the data for each bit plane input from the quantized data update control unit 155, and the transmission code amount control unit 156 performs calculation. An error correction code corresponding to the code amount thus transmitted is transmitted to the decoding side.

  As illustrated in FIG. 2, the quantized data update control unit 155 includes a threshold value determination unit 160, a data comparison unit 161, and a quantized data update unit 162.

  The threshold determination unit 160 determines a threshold used by the data comparison unit 161 based on the quantization size applied by the quantization unit 154.

  The data comparison unit 161 calculates the difference between the pre-quantization predicted image data input from the side information generation unit 153 and the corresponding pixel values (original signal and side information) of the WZ frame image (for example, calculated as an absolute value). The difference is compared with the threshold value determined by the threshold value determination unit 160.

  When the comparison result of the data comparison unit 161 indicates that the difference between the original signal and the side information is equal to or greater than the threshold value, the quantized data update unit 162 converts the first quantized data that is the output of the quantization unit 154 to the self-quantization data update unit 162. Output data (updated quantized data), and when the comparison result of the data comparison unit 161 is that the difference between the original signal and the side information is smaller than the threshold value, the output of the side information generation unit 153 Certain second quantized data is used as output data (updated quantized data) from itself.

  On the other hand, the moving picture decoding apparatus 200 includes a key frame decoding unit 201 and a Wyner-Ziv frame decoding unit 202. The Wyner-Ziv frame decoding unit 202 includes a side information generation unit 203, a Slepian-Wol decoding unit 204, and an image reconstruction unit 205.

  The key frame decoding unit 201 receives the key frame encoded by the moving image encoding device 150 (key frame encoding unit 151) and performs decoding to obtain a decoded image of the key frame.

  The side information generation unit 203 generates a predicted image of the WZ frame from the key frame before, after or after the WZ frame obtained by decoding the key frame, or from the key frame before and after the WZ frame. A plurality of pixels of a prediction image of a WZ frame are collected and quantized, and the quantized value is converted into a bit string code (binarized), and then divided into bit planes in which bits are collected for each bit of the same digit. .

  The Slepian-Wolf decoding unit 204 performs Slepian-Wolf decoding from the received error correction code and information (bit plane) of the predicted image generated by the side information generation unit 203.

  The image reconstruction unit 205 reconstructs information in units of frames by referring to the decoding result of each bit plane in the Slepian-Wolf decoding unit 204 and the prediction image information generated in the side information generation unit 203. Then, inverse quantization is performed on the reconstructed frame to obtain a decoded image of the WZ frame.

(A-2) Operation of Embodiment Next, the operation of the moving image encoding apparatus 150 of the embodiment will be described with reference to the drawings. Note that the operation of the moving picture decoding apparatus 200 is the same as the operation of the conventional moving picture decoding apparatus, and a description thereof will be omitted.

  Here, FIG. 3 is a flowchart showing the operation of the moving picture coding apparatus 150. FIG. 3 focuses on the operation of processing the WZ frame image, and for the key frame processing, the portion related to the processing of the WZ frame image is intentionally written. That is, the encoding process for the key frame is not executed every time one WZ frame image is processed, but in FIG. 3, the process related to the encoding for the key frame (steps S101 and S102) is also performed. It is described.

  The key frame image is input to the key frame encoding unit 151 and encoded by the key frame encoding unit 151 (step S101).

  The encoded data of the key frame is given to the side information generation unit 153 and transmitted to the moving picture decoding apparatus 200 (step S102).

  The encoded data of the key frame is locally decoded by the side information generation unit 153, and the local decoding key frame having a predetermined time relationship is used with respect to the WZ frame currently being processed, so that the WZ frame image A predicted image is generated, and this predicted image is input to the quantized data update control unit 155 as pre-quantization data. Further, quantization, binarization, and bit-plane division are performed on the predicted image. The data is provided as second quantized data to the quantized data update control unit 155 and the code amount control unit 156 (step S103).

  The WZ frame image is given to the quantization unit 154 and the quantized data update control unit 155 (step S104).

  The quantization unit 154 performs quantization, binarization, and bit-plane division on the WZ frame image, and the processed data becomes first quantized data as well as the quantized data update control unit 155. (Step S105).

  The first quantized data is determined by the quantized data update control unit 155 to determine whether or not it is valid, and is updated when it is determined that it is not valid. Quantized data) is provided to the code amount control unit 156 and the Lepian-Wolf encoding unit 157 (step S106). Such an update operation (review operation) of the quantized data in the quantized data update control unit 155 is repeatedly executed for all data for each pixel (step S107).

  The code amount control unit 156 calculates the necessary code amount (transmission code amount) using the second quantized data and the updated quantized data (step S108). As a calculation method and control method of the transmission code amount, a method of controlling by feedback from the decoding side as in the technique described in Non-Patent Document 1, a method of controlling without feedback as in the technique described in Non-Patent Document 2, and the like However, any method may be applied, and the method is not limited.

  The updated quantized data for each bit plane output from the quantized data update control unit 155 is subjected to Slepian-Wolf coding by the Slepian-Wolf coding unit 110, and an error correction code obtained by the Slepian-Wolf coding. Is transmitted to the decoding side by the amount of code calculated by the transmission code amount control unit 156 (step S109).

  FIG. 4 is a flowchart showing details of the operation (step S106) executed by the quantized data update control unit 155.

  The quantization size is provided from the quantization unit 154 to the threshold value determination unit 160, and the threshold value determination unit 160 determines a threshold value based on the quantization size and provides it to the data comparison unit 161 (step S151). The data of the prediction image before quantization and the WZ frame image obtained by the side information generation unit 153 are provided to the data comparison unit 161 (step S152). The operation (step S106) executed by the quantized data update control unit 155 is repeatedly executed as shown in FIG. 3, but the processes in steps S151 and S152 are executed only for the first time of the repetition process. May be.

  The difference between the original signal related to a pixel in the WZ frame image and the side information related to the pixel in the predicted image is calculated by the data comparison unit 161, and the obtained difference is compared with the threshold value determined by the threshold value determination unit 160. (Step S153).

  The first quantized data that is the output of the quantizing unit 154 and the second quantized data that is the output of the side information generating unit 153 are input to the quantized data updating unit 162 (step S154).

  When the comparison result in the data comparison unit 161 is a result that the difference between the original signal and the side information is smaller than the threshold value (positive result in step S155), the second value as the value of the updated quantized data in the data update corresponding part is Is selected (updated) (step S156). On the other hand, when the comparison result in the data comparison unit 161 is a result that the difference between the original signal and the side information is equal to or larger than the threshold value (negative result in step S155), as the value of the updated quantized data in the data update corresponding part The value of the first quantized data is selected (step S157). After determining the updated quantized data, the process proceeds to step S107 in FIG.

  Hereinafter, the update process of the quantized data in the quantized data update control unit 155 will be described with specific numerical values.

  As shown in FIG. 5A, consider a case where the original signal (□) is 130 and the side information (◯) estimated on the encoding side is 120. In the following, for simplicity, the number of bit planes will be described as 1 (quantization size = 128). The original signal (□) 130 is quantized to a quantized value “1” as shown in FIG. 5 (B1), and the side information (◯) is quantized to a quantized value “0”.

  The difference between the original signal (□) 130 and the side information (◯) 120 is calculated and compared with a threshold value (see step S153). FIG. 5 shows an example in which the quantization size is 128 (meaning that the value of 0 to 255 is expressed by 0 or 1), and the threshold is determined to be 1/2 of the quantization size. If so, the threshold value is 128 (quantization) / 2 = 64. Therefore, the comparison at this time is a comparison between 130 (original signal value) −120 (side information value) = 10 and the threshold value 64.

  Since the difference 10 between the original signal (□) 130 and the side information (◯) 120 is smaller than the threshold value 64, the quantization value “0” of the side information (◯) is selected as the updated quantized data. In other words, the quantization value “1” of the original signal (□) is updated to the quantization value “0” of the side information.

  Thereafter, the updated quantized value “0” is subjected to Slepian-Wolf coding, and parity bits are transmitted to the decoding side in the case of Turbo code, and syndrome bits are transmitted to the decoding side in the case of LDPC coding (however, as in this example) In addition, when it is completely the same as the side information, it may be notified that the information is the same as the side information without performing the Slepian-Wolf coding).

  On the other hand, on the decoding side, the error correction decoding is performed by the Slepian-Wolf decoding, and then the quantized value “0” is decoded. In the case of this example, the quantized value “0” is the same as the quantized value related to the side information on the receiving side. Therefore, as shown in FIG. The final decoded value (pixel value) is used.

  When the update process is not performed as in the conventional case shown in FIG. 9 described above, the difference (62) between the original signal and the decoded value becomes large, resulting in significant degradation. By adaptively performing the value update process, the difference (10) between the original signal and the decoded value is reduced.

  FIG. 6 shows that the number of bit planes is 2 (quantization size = 64). A quantization size of 64 means that the value of 0 to 255 is expressed by four values “00”, “01”, “10”, and “11”.

  As shown in FIG. 6A, considering that the original signal (□) is 130 and the side information (◯) estimated on the encoding side is 120, the original signal (□) 130 is shown in FIG. ) Is quantized to a quantized value “10”, and the side information (◯) is quantized to a quantized value “01”.

  When the difference between the original signal (□) 130 and the side information (◯) 120 is calculated and compared with the threshold value 32 (= 64/2) (see step S153), the original signal (□) 130 and the side information (◯) 120 are compared. The result that the difference 10 is smaller than the threshold value 32 is obtained. Therefore, the quantization value “01” of the side information (◯) is selected as the updated quantized data. In other words, the quantization value “10” of the original signal (□) is updated to the quantization value “01” of the side information. Thereafter, the updated quantized value “01” is subjected to Slepian-Wolf coding for each bit plane, and an error correction code is transmitted to the decoding side.

  On the other hand, on the decoding side, the error correction decoding is performed by the Slepian-Wolf decoding, and then the quantized value “01” is decoded. In this example, the quantized value “01” is the same as the quantized value related to the side information on the receiving side. Therefore, as shown in FIG. The final decoded value (pixel value) is used.

  Even when the quantization size is 64, the difference (10) between the original signal and the decoded value can be kept small by adaptively performing the update process of the quantization value.

  As is clear from the above, the operation is the same even if the quantization size is other than 128 and 64 (even if the number of bit planes increases).

(A-3) Effect of Embodiment As described above, according to the above-described embodiment, when the difference between the original signal and the side information is smaller than the threshold as quantized data that is data to be subjected to Slepian-Wolf encoding, Since the quantization value of the side information is set as an encoding target, the amount of code to be transmitted can be reduced, and the difference (distortion) between the original signal and the decoded value can be reduced. As a result, encoding efficiency can be improved.

(B) Other Embodiments In the above-described embodiment, the case of processing pixel region data has been shown, but the processing of transform coefficient region (transform-domain) data after orthogonal transform such as DCT transform is performed. The present invention can also be applied to a moving image encoding system, and the same effect can be obtained.

  In the description of the above embodiment, an example using a Turbo code and an LDPC code has been described as the Slepian-Wolf coding. However, the present invention is not limited to this, and any coding method based on the Slepian-Wolf theory may be used. The present invention can be applied and the same effect can be obtained.

  Further, in the description of the above embodiment, the case where the threshold value is set to ½ of the quantization size is shown, but the present invention is not limited to this. The threshold may be 1/4, 1/8, or the like, or a threshold given from the outside may be used.

  The communication path between the moving picture decoding apparatuses facing each other from the moving picture encoding apparatus of the above embodiment is not limited to a narrowly defined communication path, and may be a broadly defined communication path. That is, not only real-time communication but also data encoded by the moving image encoding apparatus may be recorded on a recording medium, and data read out from the recording medium by the moving image decoding apparatus may be processed.

  DESCRIPTION OF SYMBOLS 150 ... Moving image encoding device, 151 ... Key frame encoding part, 152 ... Wyner-Ziv frame encoding part, 153 ... Side information generation part, 154 ... Quantization part, 155 ... Quantized data update control part, 156 ... Encoding control unit, 157... Slepian-Wolf encoding unit, 160... Threshold determination unit, 161... Data comparison unit, 162.

Claims (7)

In a moving image encoding device including a quantization unit and a Slepian-Wolf encoding unit,
A side information generation unit that generates update candidate information from the reference frame image;
When the data of the quantization unit generated for encoding by the Slepian-Wolf encoding unit is greatly different from the update candidate information, the data of the quantization unit is updated to the update candidate information. And a quantized data update control unit. The quantized data update controller is
A data comparison unit that compares a difference between the data of the quantization unit and the update candidate information with a threshold;
A quantized data update unit that updates the data of the quantization unit to the update candidate information when a difference between the data of the quantization unit and the update candidate information is smaller than a threshold value. The moving image encoding apparatus according to 1.   The moving image encoding apparatus according to claim 2, wherein the threshold is determined based on a quantization size.   4. The moving image encoding apparatus according to claim 3, wherein the threshold value is ½ of the quantization size. A Wyner-Ziv frame code comprising: a key frame encoding device that encodes a key frame separated from a frame sequence; and a quantizing unit and a Slepian-Wolf encoding unit that encodes a non-key frame separated from the frame sequence. In a video encoding device having an encoding device,
5. A moving picture coding apparatus, wherein the moving picture coding apparatus according to claim 1 is applied as the Wyner-Ziv frame coding apparatus. A moving image encoding device according to claim 5;
A moving picture coding system comprising: a moving picture decoding apparatus for decoding key frames and non-key frames. Computer
A Slepian-Wolf encoding unit for encoding the input data into a Slepian-Wolf;
A quantization unit that generates data to be encoded by the above-described Slepian-Wolf encoding unit from an encoding target frame image, and that performs processing including quantization;
A side information generation unit that generates update candidate information from the reference frame image;
When the data of the quantization unit generated for encoding by the Slepian-Wolf encoding unit is greatly different from the update candidate information, the data of the quantization unit is updated to the update candidate information. A moving picture coding program which functions as a quantized data update control unit.

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