HK1220842B - Video decoding device,video decoding method, and program - Google Patents

Abstract

A video decoding device includes: an extraction unit which extracts pixel bit length increase information from a bitstream; an entropy decoding unit which entropy-decodes transformed data of an image included in the bitstream; a non-compression decoding unit which non-compression-decodes non-compression-encoded data of an image included in the bitstream; and a decoding control unit which controls the entropy decoding unit and the non-compression decoding unit, wherein a pixel bit length of an image corresponding to input data of the non-compression decoding unit is less than or equal to a pixel bit length of an image corresponding to input data of the entropy decoding unit, and wherein the pixel bit length of an image corresponding to input data of the non-compression decoding unit is increased based on the pixel bit length increase information.

Description

Video decoding device, video decoding method, and program

The present application is a divisional application of an invention patent application having an application date of 2011, 7/8, an application number of 201180034498.8, and an invention name of "video encoding device, video decoding device, video encoding method, video decoding method, and program".

Technical Field

The present invention relates to a video encoding apparatus and a video decoding apparatus using pixel bit length increase and non-compression encoding.

Background

As a video coding scheme intended for efficient transmission and accumulation of video information, a coding scheme of the ISO/IEC 14496-10 Advanced Video Coding (AVC) standard is described in non-patent literature (NPL) 2. Further, NPL 1 proposes improvement of compression efficiency of video encoding by extending (increasing) the pixel bit length of an input image after video encoding to enhance the operation accuracy of intra prediction and motion compensated prediction (inter prediction).

Patent literature (PTL)1 proposes that each predetermined coding unit switches between entropy coding and non-compression coding (PCM coding) to secure a fixed processing time for a video encoding apparatus or a video decoding apparatus.

Reference list

Patent document

PTL 1: japanese patent application laid-open No.2004-135251

Non-patent document

NPL 1: in 2006, J-009, Forum on Information Technology2006, Reiko Noda, Takeshi Chujoh, "Improving Video Coding Efficiency by Pixel Bit-depth increase"

NPL 2: ISO/IEC 14496-10 advanced video coding

Disclosure of Invention

Technical problem

Fig. 16 is a block diagram showing a video encoding apparatus obtained by simply combining the technique described in NPL 1 and the technique described in PTL 1. Hereinafter, the video encoding apparatus shown in fig. 16 is referred to as a typical video encoding apparatus.

The structure and operation of a typical video encoding apparatus that receives an input of each frame of digitized video and outputs a bitstream are described below with reference to fig. 16.

The video encoding apparatus shown in fig. 16 includes a pixel bit length increasing unit 101, a transformer/quantizer 102, an entropy encoder 103, an inverse transformer/inverse quantizer 104, a buffer 105, a predictor 106, a PCM encoder 107, a PCM decoder 108, a multiplexed data selector 109, a multiplexer 110, a switch 121, and a switch 122.

The video encoding apparatus shown in fig. 16 divides each frame into blocks of 16 × 16 pixel size called Macroblocks (MBs), and encodes each MB sequentially from the upper left corner of the frame. In AVC described in NPL2, each MB is further divided into blocks of 4 × 4 pixel size, and each block of 4 × 4 pixel size is encoded.

Fig. 17 is an explanatory diagram showing an example of block division in the case where a frame has a spatial resolution of QCIF (quarter common intermediate format). For simplicity, the operation of each component is described below by focusing on only the pixel values of luminance.

The pixel bit length increasing unit 101 increases the pixel bit length of the block-divided input video based on the pixel bit length increase information set from the outside. Bit _ depth _ luma is taken as the pixel bit length of the input video, and increased _ bit _ depth _ luma is taken as the pixel bit length increase information (increased pixel bit length). The pixel bit length increasing unit 101 shifts each pixel value of the input video to the left by increased _ bit _ depth _ luma bits. As a result, the output data of the pixel bit length increasing unit 101 has a pixel bit length of bit _ depth _ luma + created _ bit _ depth _ luma bits.

The prediction signal supplied from the predictor 106 is subtracted from the image whose pixel bit length has been increased output from the pixel bit length increasing unit 101, and the resultant image is input to the transformer/quantizer 102. There are two types of prediction signals, i.e., an intra prediction signal and an inter prediction signal. Each prediction signal is described below.

The intra prediction signal is a prediction signal created based on an image of a reconstructed picture having the same display time as the current picture, and is stored in the buffer 105. Referring to the 8.3.1Intra _4 × 4 prediction process of luma samples, the 8.3.2Intra _8 × 8 prediction process of luma samples, the 8.3.3Intra _16 × 16 prediction process of luma samples in NPL2, Intra prediction modes of three block sizes (i.e., Intra _4 × 4, Intra _8 × 8, and Intra _16 × 16) may be used for Intra prediction.

As can be understood from fig. 18(a) and 18(C), Intra _4 × 4 and Intra _8 × 8 are Intra prediction of 4 × 4 block size and 8 × 8 block size, respectively. Each circle (o) in fig. 18(a) and 18(C) indicates a reference pixel for intra prediction, i.e., a pixel of a reconstructed picture having the same display time as that of the current picture.

In Intra-prediction of Intra — 4 × 4, reconstructed peripheral pixels are directly set as reference pixels and used for padding (extrapolation) in 9 directions shown in fig. 18(B) to form a prediction signal. In Intra prediction of Intra — 8 × 8, pixels obtained by smoothing the peripheral pixels of the image of the reconstructed picture by the low-pass filters (1/2, 1/4, 1/2) shown below the right arrow in fig. 18(C) are set as reference signals, and used for extrapolation in 9 directions shown in fig. 18(B) to form prediction signals.

As shown in fig. 19(a), Intra — 16 × 16 is Intra prediction of a 16 × 16 block size. As an example shown in fig. 18(a), 18(B) and 18(C), each circle (o) in fig. 19(a) indicates a reference pixel for intra prediction, i.e., a pixel of a reconstructed picture having the same display time as that of the current picture. In Intra-prediction of Intra — 16 × 16, peripheral pixels of a reconstructed image are directly set as reference pixels and used for extrapolation in 4 directions shown in fig. 19(B) to form a prediction signal.

Hereinafter, an MB encoded using an intra prediction signal is referred to as an intra MB, a block size of intra prediction is referred to as an intra prediction mode, and a direction of extrapolation is referred to as an intra prediction direction.

The inter prediction signal is a prediction signal created from an image of a reconstructed picture having a different display time from the current picture, and is stored in the buffer 105. Hereinafter, an MB encoded using an inter prediction signal is referred to as an inter MB. The block size of the inter MB may be selected from, for example, 16 × 16, 16 × 8, 8 × 16, 8 × 8, 8 × 4, 4 × 8, and 4 × 4.

Fig. 20 is an explanatory diagram showing an example of inter prediction using a 16 × 16 block size as an example, the motion vector MV ═ MV (MV) shown in fig. 20_x,mv_y) Is a prediction parameter of inter prediction which indicates the amount of conversion of an inter prediction block (inter prediction signal) of a reference picture related to a block to be encoded. In AVC, the prediction parameters of inter prediction include not only an inter prediction direction indicating the direction of a reference picture of an inter prediction signal related to a picture to be encoded of a block to be encoded, but also a reference picture index identifying the reference picture of inter prediction of the block to be encoded. This is because, in AVC, a plurality of reference pictures stored in the buffer 105 can be used for inter prediction.

Inter prediction is described in more detail in the 8.4 inter prediction process in NPL 2.

Hereinafter, an MB encoded using an inter prediction signal is referred to as an inter MB, a block size of inter prediction is referred to as an inter prediction mode, and a direction of inter prediction is referred to as an inter prediction direction.

A coded picture including only intra MBs is referred to as an I picture. A coded picture including not only intra MBs but also inter MBs is referred to as a P picture. A coded picture including an inter MB that uses not one reference picture but two reference pictures at the same time for inter prediction is referred to as a B picture. In the B picture, inter prediction in which the direction of a reference picture of an inter prediction signal related to a picture to be encoded of a block to be encoded points to the past is called forward prediction, inter prediction in which the direction of a reference picture of an inter prediction signal related to a picture to be encoded of a block to be encoded points to the future is called backward prediction, and inter prediction involving both the past and the future is called bidirectional prediction.

The transformer/quantizer 102 frequency-transforms an image (prediction error image) in which the pixel bit length of the prediction signal has been subtracted has been increased.

The transformer/quantizer 102 further quantizes the frequency-transformed prediction error image (frequency transform coefficients) using a quantization step Qs according to the increased pixel bit length increased _ bit _ depth _ luma of the pixel bit length increasing unit 101. Will Qs_lumaAs the normal quantization step size. Then, as an example, Qs is Qs_luma*2^{increased_bit_depth_luma}. Hereinafter, the quantized frequency transform coefficient is referred to as a transform quantization value.

The entropy encoder 103 entropy encodes the prediction parameter and the transform quantization value. The prediction parameters are information related to MB prediction, such as intra MB/inter MB, intra prediction mode, intra prediction direction, inter MB block size, and motion vector described above.

The inverse transformer/inverse quantizer 104 inversely quantizes the transformed quantized value using a quantization step size according to the increased pixel bit length increased _ bit _ depth _ luma of the pixel bit length increasing unit 101. The inverse transformer/inverse quantizer 104 further performs inverse frequency transform on the frequency transform coefficient obtained by the inverse quantization. The prediction signal is added to the reconstructed prediction error image obtained by the inverse frequency transform, and the resultant image is supplied to the switch 122.

The multiplexed data selector 109 monitors the amount of input data to each predetermined coding unit (e.g., macroblock) of the entropy encoder 103. In the case where the entropy encoder 103 can entropy encode the input data within a processing time corresponding to a predetermined encoding unit, the multiplexed data selector 109 controls the switch 121 to select the output data of the entropy encoder 103. As a result, the output data of the entropy encoder 103 is supplied to the multiplexer 110 via the switch 121. The multiplexed data selector 109 further controls the switch 122 to select the output data of the inverse transformer/inverse quantizer 104. As a result, the output data of the inverse transformer/inverse quantizer 104 is supplied to the buffer 105 via the switch 122.

In the case where the entropy encoder 103 cannot entropy encode the input data within the processing time, the multiplexed data selector 109 controls the switch 121 to select the output data obtained by the PCM encoder 107 by PCM-encoding the output data of the pixel bit length increasing unit 101. As a result, the output data of the PCM encoder 107 is supplied to the multiplexer 110 via the switch 121. The multiplexed data selector 109 further controls the switch 122 to select the output data obtained by the PCM decoder 108 by PCM decoding the output data of the PCM encoder 107. As a result, the output data of the PCM decoder 108 is supplied to the multiplexer 110 via the switch 122.

The buffer 105 stores the reconstructed image supplied via the switch 122. The reconstructed image of each frame is called a reconstructed picture.

The multiplexer 110 multiplexes the pixel bit length increase information with the output data of the entropy encoder 103 and the output data of the PCM encoder 107, and outputs a multiplexing result.

A typical video encoding apparatus creates a bitstream based on the above-described operations.

In the case of using the above-described typical technique, it is possible to secure a fixed processing time for a video encoding apparatus or a video decoding apparatus while enhancing the calculation accuracy of intra prediction or inter prediction by pixel bit length extension.

However, in the above-described exemplary technique, an image with an increased pixel bit length is PCM-encoded, which leads to a problem that PCM-encoded output data increases the pixel bit length increase without obtaining PSNR (peak signal-to-noise ratio) improvement. For example, in case bit _ depth _ luma is 8 bits and increased _ bit _ depth _ luma is 8 bits, the PCM encoded output data is 16 bits, which is twice as much as an 8-bit input image.

In view of the above, it is an object of the present invention to suppress an increase in PCM encoded output data in video encoding based on an increase in pixel bit length and PCM encoding.

Solution to the problem

A video decoding apparatus according to the present invention includes: an extraction unit that extracts pixel bit length increase information of luminance and pixel bit length increase information of color difference from a bitstream; an entropy decoding unit entropy-decoding transformed data of an image included in the bitstream; a non-compression decoding unit that non-compression-decodes non-compression-encoded data of an image included in the bitstream; and a decoding control unit that controls the entropy decoding unit and the non-compression decoding unit, wherein a pixel bit length of an image corresponding to input data of the non-compression decoding unit is different from a pixel bit length of an image corresponding to input data of the entropy decoding unit, and wherein a pixel bit length of a decoded image obtained by the non-compression decoding is increased based on the pixel bit length increase information of the luminance and the pixel bit length increase information of the color difference.

A video decoding method according to the present invention includes: extracting pixel bit length increase information of luminance and pixel bit length increase information of color difference from the bitstream; entropy-decoding transformed data of an image included in the bitstream; non-compression decoding non-compression encoded data of an image included in the bitstream; and controlling the entropy decoding and the non-compression decoding, wherein a pixel bit length of an image corresponding to the non-compression decoded input data is different from a pixel bit length of an image corresponding to the entropy decoded input data, and wherein a pixel bit length of a decoded image obtained by the non-compression decoding is increased based on the pixel bit length increase information of the luminance and the pixel bit length increase information of the color difference.

A computer-readable information recording medium storing a video decoding program according to the present invention, the video decoding program, when executed by a processor, performs: a process of extracting pixel bit length increase information of luminance and pixel bit length increase information of color difference from the bit stream; a process of entropy-decoding transformed data of an image in the bitstream; a process of performing non-compression decoding on non-compression encoded data of an image in the bitstream; and controlling the processes of the entropy decoding and the non-compression decoding, wherein a pixel bit length of an image corresponding to the non-compression decoded input data is different from a pixel bit length of an image corresponding to the entropy decoded input data, and wherein a pixel bit length of a decoded image obtained by the non-compression decoding is increased based on the pixel bit length increase information of the luminance and the pixel bit length increase information of the color difference.

Advantageous effects of the invention

According to the present invention, it is possible to suppress an increase in output data of PCM encoding in video encoding based on an increase in pixel bit length and PCM encoding.

Drawings

Fig. 1 is a block diagram of a video encoding apparatus in exemplary embodiment 1.

Fig. 2 is an explanatory diagram showing pixel bit length increase information in the sequence parameters.

Fig. 3 is a flowchart showing a process of the video encoding apparatus in exemplary embodiment 1.

Fig. 4 is a block diagram of a video encoding apparatus in exemplary embodiment 2.

Fig. 5 is a flowchart showing a process of the video encoding apparatus in exemplary embodiment 2.

Fig. 6 is a block diagram of a video encoding apparatus in another exemplary embodiment.

Fig. 7 is an explanatory diagram showing another example of pixel bit length increase information in the sequence parameter.

Fig. 8 is an explanatory diagram showing still another example of pixel bit length increase information in the sequence parameter.

Fig. 9 is an explanatory diagram showing another example of pixel bit length increase information in the sequence parameter.

Fig. 10 is a block diagram showing an example of the structure of an information processing system capable of realizing the functions of a video encoding apparatus and a video decoding apparatus according to the present invention.

Fig. 11 is a block diagram showing a main part of a video encoding apparatus according to the present invention.

Fig. 12 is a block diagram showing the main part of another video encoding apparatus according to the present invention.

Fig. 13 is a block diagram showing a main part of still another video encoding apparatus according to the present invention.

Fig. 14 is a block diagram showing a main part of a video decoding apparatus according to the present invention.

Fig. 15 is a block diagram showing the main part of another video decoding apparatus according to the present invention.

Fig. 16 is a block diagram showing a typical video encoding apparatus.

Fig. 17 is an explanatory diagram showing an example of block division.

Fig. 18(a), 18(B) and 18(C) are explanatory diagrams showing the prediction types.

Fig. 19(a) and 19(B) are explanatory diagrams showing the prediction type.

Fig. 20 is an explanatory diagram showing an example of inter prediction using a 16 × 16 block size as an example.

Detailed Description

Exemplary embodiment 1

The video encoding apparatus in this exemplary embodiment includes: means for making a pixel bit length of an image corresponding to the entropy-encoded output data and a pixel bit length of an image corresponding to the PCM-encoded output data different from each other; means for increasing a pixel bit length of a decoded image of the PCM decoding based on the pixel bit length increase information; and means for multiplexing the pixel bit length increase information into the bitstream.

As shown in fig. 1, the video encoding apparatus in this exemplary embodiment includes a pixel bit length increasing unit 111 for increasing the pixel bit length of a decoded image of the PCM decoder 108 based on pixel bit length increase information, in addition to the pixel bit length increasing unit 101, the transformer/quantizer 102, the entropy encoder 103, the inverse transformer/inverse quantizer 104, the buffer 105, the predictor 106, the PCM encoder 107, the PCM decoder 108, the multiplexed data selector 109, the multiplexer 110, the switch 121, and the switch 122 included in the typical video encoding apparatus shown in fig. 16.

When fig. 1 and fig. 16 are compared, it can be understood that the video encoding apparatus in this exemplary embodiment supplies the input image before the pixel bit length is increased to the PCM encoder 107 so as to make the pixel bit length of the image corresponding to the entropy-encoded output data and the pixel bit length of the image corresponding to the PCM-encoded output data different from each other. The image corresponding to the entropy-encoded output data is a reconstructed image of the input video, which has been supplied to the transformer/quantizer 102 with the increased pixel bit length, and the image of the input video, which has been supplied from the inverse transformer/inverse quantizer 104 with the increased pixel bit length. The pictures corresponding to the PCM encoded output data are pictures of the input video having no increase in pixel bit length supplied to the PCM encoder 107, and PCM decoded pictures of the input video having no increase in pixel bit length supplied from the PCM decoder 108.

The pixel bit length increasing unit 101 increases the pixel bit length of the block-divided input video based on the pixel bit length increase information set from the outside.

Bit _ depth _ luma is taken as the pixel bit length of luminance of the input video, and increased _ bit _ depth _ luma is taken as the pixel bit length increase information (increased pixel bit length) of luminance. The pixel bit length increasing unit 101 shifts each pixel value of the luminance of the input video to the left by increased _ bit _ depth _ luma bits. As a result, the output data of the pixel bit length increasing unit 101 has a pixel bit length of bit _ depth _ luma + created _ bit _ depth _ luma bits. Also, for color differences (Cb and Cr components), bit _ depth _ chroma is taken as the pixel bit length of the color difference of the input video, and increased _ bit _ depth _ chroma is taken as the pixel bit length increase information of the color difference. The pixel bit length increasing unit 101 shifts each pixel value of color differences of the input video to the left by increased _ bit _ depth _ luma bits.

The prediction signal supplied from the predictor 106 is subtracted from the image whose pixel bit length has been increased output from the pixel bit length increasing unit 101, and the resultant image is input to the transformer/quantizer 102. The transformer/quantizer 102 frequency-transforms an image (prediction error image) in which the pixel bit length of the prediction signal has been subtracted has been increased.

The transformer/quantizer 102 further quantizes the frequency-transformed prediction error image (frequency transform coefficients) using a quantization step Qs according to the increased pixel bit length increased _ bit _ depth _ luma and increased _ bit _ depth _ chroma of the pixel bit length increasing unit 101. Will Qs_lumaAs the normal quantization step size for luminance. Then, as an example, Qs is Qs_luma*2^{increased_bit_depth_luma}. Hereinafter, the quantized frequency transform coefficient is referred to as a transform quantization value.

The entropy encoder 103 entropy encodes the prediction parameters supplied from the predictor 106 and the transform quantization values supplied from the transformer/quantizer 102. The prediction parameters are information related to macroblock prediction, such as intra MB/inter MB, intra prediction mode, intra prediction direction, inter MB block size, and motion vector.

The inverse transformer/inverse quantizer 104 inversely quantizes the transformed quantized value using quantization steps according to the increased pixel bit lengths increased _ bit _ depth _ luma and increased _ bit _ depth _ chroma of the pixel bit length increasing unit 101. The inverse transformer/inverse quantizer 104 further performs inverse frequency transform on the frequency transform coefficient obtained by the inverse quantization. The prediction signal is added to the reconstructed prediction error image obtained by the inverse frequency transform, and the resultant image is supplied to the switch 122.

The PCM encoder 107 PCM encodes the input image before the increase in the pixel bit length. The output data PCM _ sample _ luma [ i ] of the luminance of the PCM encoder 107 has a pixel bit length bit _ depth _ luma of the luminance of the input video. Here, i (0 ≦ i ≦ 255) is an index of the raster scan order among the macroblocks. Also, the output data PCM _ sample _ chroma [ i ] (i:0 ≦ i ≦ 127) of the color difference of the PCM encoder 107 has the pixel bit length bit _ depth _ chroma of the color difference of the input video.

The PCM decoder 108 PCM decodes PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ]. Hereinafter, PCM decoding is also referred to as PCM data reading.

The pixel bit length increasing unit 111 shifts the PCM data read PCM _ sample _ luma [ i ] by the increased _ bit _ depth _ chroma bits to the left. As a result, the reconstructed image obtained via the PCM decoder 108 has bit _ depth _ luma + interpolated _ bit _ depth _ luma bits and is provided to the switch 122. Likewise, pcm _ sample _ chroma [ i ] is shifted to the left by increased _ bit _ depth _ chroma bits and provided to switch 122.

The multiplexed data selector 109 monitors the amount of input data to each predetermined coding unit (e.g., macroblock) of the entropy encoder 103. In the case where the entropy encoder 103 can entropy encode the input data within a processing time corresponding to a predetermined encoding unit, the multiplexed data selector 109 controls the switch 121 to select the output data of the entropy encoder 103. As a result, the output data of the entropy encoder 103 is supplied to the multiplexer 110 via the switch 121. The multiplexed data selector 109 further controls the switch 122 to select the output data of the inverse transformer/inverse quantizer 104. As a result, the output data of the inverse transformer/inverse quantizer 104 is supplied to the buffer 105 via the switch 122.

In the case where the entropy encoder 103 cannot entropy encode the input data within the processing time, the multiplexed data selector 109 first causes the entropy encoder 103 to encode and outputs information indicating that the macroblock is an intra MB of PCM. In detail, when the 7.3.5 macroblock layer syntax in NPL2 is conformed, mb _ type is entropy-encoded and output as I _ PCM.

After that, the output bits of the entropy encoder 103 are bit aligned. In detail, when conforming to the 7.3.5 macroblock layer syntax in NPL2, the entropy encoder 103 provides a predetermined number of pcm _ alignment _ zero _ bits to the multiplexer 110. In addition, the entropy encoder 103 initializes the encoding engine for subsequent encoding.

One example of encoding engine initialization is described in the 9.3.4.1 initialization process for the arithmetic coding engine (information rich) in NPL 2.

The multiplexed data selector 109 further controls the switch 121 to select the output data of the PCM encoder 107. As a result, the output data of the PCM encoder 107 is supplied to the multiplexer 110 via the switch 121.

Finally, the multiplexed data selector 109 controls the switch 122 to select the output data of the pixel bit length increasing unit 111. As a result, the output data of the pixel bit length increasing unit 111 is supplied to the buffer 105 via the switch 122. Here, the pixel bit length increasing unit 111 increases the number of bits by shifting the output data PCM _ sample _ luma [ i ] of the PCM decoder 108, which is obtained by reading the output data PCM _ sample _ luma [ i ] of the PCM encoder 107, to the left by the increased _ bit _ depth _ luma bits. Also, the pixel bit length increasing unit 111 increases the number of bits by shifting the output data PCM _ sample _ chroma [ i ] of the PCM decoder 108 obtained by reading the output data PCM _ sample _ chroma [ i ] of the PCM encoder 107 by an increased _ bit _ depth _ chroma bit to the left.

The multiplexer 110 multiplexes the pixel bit length increase information with the output data of the entropy encoder 103 and the output data of the PCM encoder 107, and outputs a multiplexing result. When the specification of syntax function, category, and descriptor in NPL2 is satisfied, pixel bit length increase information (increment _ bit _ depth _ luma and increment _ bit _ depth _ chroma) may be multiplexed after bit _ depth _ luma _ minus8 and bit _ depth _ chroma _ minus8 of the sequence parameters as shown in the list shown in fig. 2. Here, bit _ depth _ luma _ minus8 is a value obtained by subtracting 8 from the pixel bit length bit _ depth _ luma of the luminance of the input video, bit _ depth _ chroma _ minus8 is a value obtained by subtracting 8 from the pixel bit length bit _ depth _ chroma of the color difference of the input video, increased _ bit _ depth _ luma is an increased pixel bit length of the luminance, and increased _ bit _ depth _ chroma is an increased pixel bit length of the color difference.

The representations ("C" and "descriptor") in the list shown in fig. 2 conform to the 7.2 specification of syntactic functions, classes and descriptors in NPL2, for example.

The video encoding apparatus in this exemplary embodiment creates a bitstream based on the above-described operations.

In the case where entropy encoding cannot be performed within the processing time, which is a feature of the present invention, the operations of the entropy encoder 103, the PCM encoder 107, the PCM decoder 108, and the pixel bit length increasing unit 111 are described below with reference to the flowchart in fig. 3.

As shown in fig. 3, in step S101, the entropy encoder 103 entropy encodes mb _ type into I _ PCM and supplies it to the multiplexer 110 in order to secure a fixed processing time for the video encoding apparatus or the video decoding apparatus.

In step S102, the entropy encoder 103 supplies pcm _ alignment _ zero _ bit to the multiplexer 110 to byte align the output bits.

In step S103, the entropy encoder 103 initializes an encoding engine for subsequent entropy encoding.

In step S104, the PCM encoder 107 PCM-encodes the input image before the pixel bit length is increased, and supplies it to the multiplexer 110, so that the PCM-encoded output data is not increased.

In step S105, the PCM decoder 108 performs PCM decoding (PCM data reading) on the PCM encoding results PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ].

In step S106, the pixel bit length increasing unit 111 shifts PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ] of PCM data read by the PCM decoder 108 to the left by the increased _ bit _ depth _ luma and the increased _ bit _ depth _ chroma bits, respectively, so as to enhance the operation accuracy of the subsequent intra prediction and inter prediction.

Therefore, in the case where entropy encoding cannot be performed within the processing time corresponding to a predetermined coding unit, the entropy encoder 103 and the PCM encoder 107 operate as described above.

In the video encoding apparatus in this exemplary embodiment, the input image before the pixel bit length is increased is supplied to the PCM encoder 107 so that the pixel bit length of the image corresponding to the entropy-encoded output data and the pixel bit length of the image corresponding to the PCM-encoded output data are made different from each other. This structure allows suppressing an increase in output data of PCM encoding in video encoding based on an increase in pixel bit length and non-compression encoding.

Further, the video encoding apparatus in this exemplary embodiment includes a pixel bit length increasing unit 111 for increasing a pixel bit length of a decoded image of PCM decoding based on the pixel bit length increase information. The pixel bit length increasing unit 111 can suppress a decrease in the operation accuracy of the intra prediction and the inter prediction due to making the pixel bit lengths different from each other.

Further, in the video encoding apparatus in this exemplary embodiment, the multiplexer 110 multiplexes the pixel bit length increase information into the bit stream, thereby equivalently increasing the pixel bit length of the decoded image of the PCM decoding in the video decoding. This structure contributes to enhancing the interoperability of the video encoding apparatus and the video decoding apparatus. That is, the video encoding apparatus and the video decoding apparatus cooperate with each other, and an increase in PCM encoding in the system can be suppressed, and a decrease in the computational accuracy of intra prediction and inter prediction can also be suppressed.

Exemplary embodiment 2

The video decoding apparatus in this exemplary embodiment decodes a bitstream in which the pixel bit length of an image corresponding to input data of the entropy decoding apparatus and the pixel bit length of an image corresponding to input data of the PCM decoding apparatus are different from each other. The image corresponding to the input data of the entropy decoding apparatus is a reconstructed image of an image of the input video having an increased pixel bit length supplied from an inverse transformer/inverse quantizer 206 described later. The image corresponding to the input data of the PCM decoding apparatus is a PCM decoded image of the input video whose pixel bit length is not increased supplied from the PCM decoder 203 described later.

As shown in fig. 4, the video decoding apparatus in this exemplary embodiment includes a demultiplexer 201, a decoding controller 202, a PCM decoder 203, an entropy decoder 204, a pixel bit length increasing unit 205, an inverse transformer/inverse quantizer 206, a predictor 207, a buffer 208, a pixel bit length decreasing unit 209, a switch 221, and a switch 222.

The demultiplexer 201 demultiplexes the input bitstream to extract the pixel bit length increase information and the entropy-encoded or PCM-encoded video bitstream. When the specification of syntax function, category, and descriptor in NPL2 is satisfied, pixel bit length increase information (increased _ bit _ depth _ luma and increased _ bit _ depth _ chroma) after bit _ depth _ chroma minus8 and bit _ depth _ chroma 8 of the sequence parameters shown in the list shown in fig. 2 is extracted.

The entropy decoder 204 entropy decodes the video bitstream. In the case where mb _ type of the macroblock is not I _ PCM (PCM coding), the entropy decoder 204 entropy-decodes the prediction parameters and the transform quantization values of the macroblock and provides them to the inverse transformer/inverse quantizer 206 and the predictor 207.

The inverse transformer/inverse quantizer 206 inversely quantizes the transformed quantized values of luminance and color difference using quantization steps according to the pixel bit length increase information increased _ bit _ depth _ luma and increased _ bit _ depth _ chroma extracted by demultiplexing. The inverse transformer/inverse quantizer 206 further performs inverse frequency transform on the frequency transform coefficient obtained by the inverse quantization.

The predictor 207 creates a prediction signal using the image of the reconstructed picture stored in the buffer 208 based on the entropy-decoded prediction parameters.

The prediction signal supplied from the predictor 207 is added to the reconstructed prediction error image obtained by the inverse frequency transform by the inverse transformer/inverse quantizer 206, and the resultant image is supplied to the switch 222.

The decoding controller 202 changes the switch 222 so that the reconstructed prediction error image to which the prediction signal has been added is supplied to the buffer 208 as a reconstructed image.

In the case where mb _ type of the macroblock is PCM encoding, the decoding controller 202 causes the demultiplexer 201 to byte align the video stream in the middle of entropy decoding. When conforming to the 7.3.5 macroblock layer syntax in NPL2, the decoding controller 202 causes the demultiplexer 201 to read the pcm _ alignment _ zero _ bit until the video bitstream is byte aligned.

The decoding controller 202 then causes the entropy decoder 204 to initialize the decoding engine. One example of decoding engine initialization is described in the 9.3.1.2 initialization process for the arithmetic decoding engine in NPL 2.

After that, the decoding controller 202 changes the switch 221 so that the byte-aligned video bit stream is supplied to the PCM decoder 203.

The PCM decoder 203 PCM decodes (PCM data read) PCM encoded luminance data PCM _ sample _ luma [ i ] and color difference data PCM _ sample _ chroma [ i ] from the byte-aligned video bitstream.

The pixel bit length increasing unit 205 shifts the PCM data read PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ] to the left, respectively, according to the pixel bit length increase information increased _ bit _ depth _ luma and increased _ bit _ depth _ chroma extracted by demultiplexing. When the description of the 8.3.5 sample construction process for the I _ PCM macroblock in NPL2 is complied with, the PCM-decoded luminance image S ' L and the PCM-decoded color difference images S ' Cb and S ' Cr are calculated according to the following equations (8-154 ') and (8-155 ').

The decoding controller 202 changes the switch 222 so that the PCM-decoded image whose pixel bit length has been increased is supplied to the buffer 208 as a reconstructed image. The decoding controller 202 changes the switch 221 so that the output data of the demultiplexer 201 is supplied to the entropy decoder 204 to decode the next macroblock.

The pixel bit length reduction unit 209 reduces the pixel bit length of the reconstructed picture stored in the buffer 208 according to the pixel bit length increase information acquired _ bit _ depth _ luma and acquired _ bit _ depth _ chroma extracted by demultiplexing, and outputs the result.

The video encoding apparatus in this exemplary embodiment creates a decoded image based on the above-described operation.

The operation of the decoding controller 202, the entropy decoder 204, the PCM decoder 203, and the pixel bit length increasing unit 205 in the case where mb _ type of a macroblock is PCM encoding, which is a feature of the present invention, is described below with reference to the flowchart in fig. 5.

In step S201, the demultiplexer 201 reads pcm _ alignment _ zero _ bit in order to byte align the video bitstream in the middle of entropy decoding.

In step S202, the entropy decoder 204 initializes the decoding engine for subsequent entropy decoding.

In step S203, the PCM decoder 203 performs PCM decoding (PCM data reading) on the PCM encoding results PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ].

In step S204, the pixel bit length increasing unit 205 shifts PCM data read PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ] to the left by the increased _ bit _ depth _ luma bits and the increased _ bit _ depth _ chroma bits, respectively, so as to enhance the accuracy of the subsequent intra prediction and inter prediction operations.

Accordingly, in the case where mb _ type of the macroblock is PCM encoding, the decoding controller 202, the entropy decoder 204, the PCM decoder 203, and the pixel bit length increasing unit 205 operate as described above.

The video encoding apparatus in this exemplary embodiment includes a pixel bit length increasing unit 205 for increasing the pixel bit length of a decoded image of PCM decoding based on pixel bit length increase information extracted by demultiplexing. The pixel bit length increasing unit 205 can suppress a decrease in the operation accuracy of the intra prediction and the inter prediction due to making the pixel bit lengths of the images corresponding to the inputs of the entropy decoding apparatus and the PCM decoding apparatus different from each other. Furthermore, the same reconstructed image as in video decoding can be obtained, which contributes to enhancement of interoperability of the video encoding apparatus and the video decoding apparatus. That is, the video encoding apparatus and the video decoding apparatus cooperate with each other, and an increase in PCM encoding in the system can be suppressed, and a decrease in the computational accuracy of intra prediction and inter prediction can also be suppressed.

The video encoding apparatus in exemplary embodiment 1 shown in fig. 1 is a video encoding apparatus that supplies an input image before an increase in pixel bit length to the PCM encoder 107 so as to make the pixel bit length of an image corresponding to entropy-encoded output data and the pixel bit length of an image corresponding to PCM-encoded output data different from each other.

Fig. 6 is a block diagram showing a video encoding apparatus of another structure for achieving the same advantageous effects as the video encoding apparatus shown in fig. 1.

When compared with the video encoding apparatus shown in fig. 1, the video encoding apparatus shown in fig. 6 additionally includes a pixel bit length reduction unit 112. That is, the video encoding apparatus shown in fig. 6 has a structure in which the pixel bit length reduction unit 112 that receives the image whose pixel bit length has been increased supplies the PCM encoder 107 with the image whose pixel bit length has been reduced based on the pixel bit length increase information. As shown in exemplary embodiment 1, the video encoding apparatus shown in fig. 6 can suppress an increase in output data of PCM encoding, and can also suppress a decrease in the operation accuracy of intra prediction and inter prediction due to making the pixel bit lengths different from each other.

In each of the above exemplary embodiments, the pixel of the reconstructed picture is a pixel whose pixel bit length has been increased. However, in order to reduce the size of the buffer for storing the reconstructed picture, an exemplary embodiment may be conceived in which the above-described pixel bit length increasing unit and pixel bit length decreasing unit are used for input/output of the buffer. Also, in such an exemplary embodiment, it is possible according to the present invention to achieve suppression of an increase in output data of PCM encoding and suppression of a decrease in operation accuracy of intra prediction due to making pixel bit lengths different from each other.

In each of the above exemplary embodiments, the PCM decoder and the pixel bit length increasing unit are independent functional blocks. However, as can be easily understood from equations (8-154 ') and (8-155'), the PCM decoder and the pixel bit length increasing unit may be integrated into one functional block.

In each of the above exemplary embodiments, the video encoding apparatus multiplexes the encrypted _ bit _ depth _ luma and encrypted _ bit _ depth _ chroma into the bitstream after the bit _ depth _ luma _ minus8 and the bit _ depth _ chroma _ minus8 to explicitly signal the pixel bit length increase information to the video decoding apparatus (see fig. 2). Alternatively, the video encoding apparatus may multiplex the pixel bit length after the pixel bit length increase into a bitstream as pixel bit length increase information so as to implicitly signal the pixel bit length increase information to the video decoding apparatus (it is assumed here that the original pixel bit length of the input video is 8 bits in the video encoding apparatus and the video decoding apparatus).

In this case, the video encoding device multiplexes the pixel bit length increase information (internal _ bit _ depth _ luma _ minus8 and internal _ bit _ depth _ chroma _ minus8) shown in fig. 7 into the sequence parameters instead of the bit _ depth _ luma _ minus8 and bit _ depth _ chroma _ minus8 of the sequence parameters. Here, the internal _ bit _ depth _ luma _ minus8 is a value of the interrupted _ bit _ depth _ luma, and the internal _ bit _ depth _ chroma _ minus8 is a value of the interrupted _ bit _ depth _ chroma.

In the case where the pixel bit length increase information shown in fig. 7 is multiplexed into the sequence parameters, the PCM encoder 107 PCM-encodes the input image before the pixel bit length is increased. That is, the PCM encoder 107 PCM-encodes 8 bits PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ]. The PCM decoder 108 decodes 8 bits PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ]. The pixel bit length increasing unit 111 shifts PCM-decoded PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ] left by increased _ bit _ depth _ luma bits and increased _ bit _ depth _ chroma bits, respectively.

The video decoding apparatus corresponding to the case of multiplexing the pixel bit length increase information shown in fig. 7 into the sequence parameters demultiplexes the pixel bit length increase information (internal _ bit _ depth _ luma _ minus8 and internal _ bit _ depth _ chroma _ minus8) from the sequence parameters, and calculates the interrupted _ bit _ depth _ luma and the interrupted _ bit _ depth _ chroma as follows.

increased_bit_depth_luma＝internal_bit_depth_luma_minus8

increased_bit_depth_chroma＝internal_bit_depth_chroma_minus8

Through the above calculation, the video decoding apparatus can demultiplex the pixel bit length increase information implicitly signaled by the video encoding apparatus.

In the case where the above-described video encoding apparatus implicitly signals the pixel bit length increase information to the video decoding apparatus, there is a problem that PCM encoding cannot be performed due to no distortion when the original pixel bit length of the input video is longer than 8 bits. For example, when the original pixel bit length of the input video is 10 bits, 8 bits pcm _ sample _ luma [ i ] and pcm _ sample _ chroma [ i ] are used to generate quantization distortion.

When the original pixel bit length of the input video is N bits (N >8), in order to support PCM encoding without quantization distortion, PCM _ sample _ bit _ depth _ is _ internal _ bit _ depth _ flag, which is a flag bit indicating whether the bit length of the PCM is the pixel bit length after the pixel bit length is increased, may be added to the sequence parameters shown in fig. 8.

In the case where PCM _ sample _ bit _ depth _ is _ internal _ bit _ depth _ flag is 0, the PCM encoder 107 PCM encodes the input image before the increase in the pixel bit length. That is, the PCM encoder 107 PCM-encodes PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ]. The pixel bit length increasing unit 111 shifts PCM-encoded PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ] to the left by increased _ bit _ depth _ luma (═ internal _ bit _ depth _ luma _ minus8) bits and increased _ bit _ depth _ chroma (═ internal _ bit _ depth _ chroma _ minus8) bits, respectively.

In the case where PCM _ sample _ bit _ depth _ is _ internal _ bit _ depth _ flag is 1, the PCM encoder 107 PCM encodes the image whose pixel bit length has been increased. That is, the PCM encoder 107 PCM encodes PCM _ sample _ luma [ i ] of N bits (internal _ bit _ depth _ luma _ minus8+8 bits) and PCM _ sample _ chroma [ i ] of N bits (internal _ bit _ depth _ chroma _ minus8+8 bits). The PCM decoder 108 PCM-decodes the N bits of PCM _ sample _ luma [ i ] and the N bits of PCM _ sample _ chroma [ i ]. The pixel bit length increasing unit 111 shifts the PCM-decoded PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ] to the left by 0 bits (i.e., does not shift the PCM-decoded PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ] to the left).

When the original pixel bit length of the input video is N bits (N >8), in order to support PCM encoding without quantization distortion, PCM _ sample _ bit _ depth _ luma _ minus8 and PCM _ sample _ bit _ depth _ chroma _ minus8, which are bit lengths of PCM of luminance and color difference, respectively, may be added to the sequence parameters, as shown in fig. 9, in place of PCM _ sample _ bit _ depth _ is _ internal _ bit _ depth _ flag.

With the addition of PCM _ sample _ bit _ depth _ luma _ minus8 and PCM _ sample _ bit _ depth _ chroma _ minus8 to the sequence parameters, the PCM encoder 107 PCM encodes PCM _ sample _ bit _ depth _ luma [ i ] of PCM _ sample _ bit _ depth _ luma _ minus8+8 bits and PCM _ sample _ bit _ depth _ chroma [ i ] of PCM _ sample _ bit _ depth _ chroma _ minus8+8 bits. With the addition of PCM _ sample _ bit _ depth _ luma _ minus8 and PCM _ sample _ bit _ depth _ chroma _ minus8 to the sequence parameters, the PCM decoder 108 PCM decodes PCM _ sample _ luma [ i ] of PCM _ sample _ bit _ depth _ luma _ minus8+8 bits and PCM _ sample _ bit _ depth _ chroma _ minus8+8 bits. The pixel bit length increasing unit 111 shifts PCM-decoded PCM _ sample _ luma [ i ] and PCM _ sample _ chroma [ i ] left by increased _ bit _ depth _ luma bits and increased _ bit _ depth _ chroma bits, respectively. Here, the interrupted _ bit _ depth _ luma and the interrupted _ bit _ depth _ chroma are calculated as follows.

increased_bit_depth_luma＝internal_bit_depth_luma_minus8–

pcm_sample_bit_depth_luma_minus8

increased_bit_depth_chroma＝internal_bit_depth_chroma_minus8–

pcm_sample_bit_depth_chroma_minus8

As is clear from the above calculations, in the case where the interrupted _ bit _ depth _ luma is greater than 0 and the internal _ bit _ depth _ luma _ minus8+8 is less than N, the video encoding device implicitly signals the pixel bit length increase information to the video decoding device; and likewise in the case where internal _ bit _ depth _ chroma _ minus8+8 is less than N, the video encoding device implicitly signals the pixel bit length increase information to the video decoding device.

Each of the above exemplary embodiments may be implemented by hardware or may be implemented by a computer program.

The information processing system shown in fig. 10 includes a processor 1001, a program memory 1002, a storage medium 1003 for storing video data, and a storage medium 1004 for storing a bitstream. The storage medium 1003 and the storage medium 1004 may be separate storage media, or may be a storage area composed of the same storage medium. A magnetic storage medium (e.g., a hard disk) may be used as the storage medium.

In the information processing system shown in fig. 10, a program for realizing the functions of the blocks shown in each of fig. 1, 4, and 6 (except for the blocks of the buffer) is stored in the program memory 1002. The processor 1001 realizes the functions of the video encoding apparatus or the video decoding apparatus shown in fig. 1, 4, and 6 by performing processing according to a program stored in the program memory 1002.

Fig. 11 is a block diagram showing a main part of a video encoding apparatus according to the present invention. As shown in fig. 11, the video encoding apparatus according to the present invention includes: a pixel bit length increasing means 1 (e.g., a pixel bit length increasing unit 101 shown in fig. 1) for increasing a pixel bit length of an input image based on pixel bit length increase information; a transforming means 2 (e.g., transformer/quantizer 102 shown in fig. 1) for transforming the output data of the pixel bit length increasing means 1; entropy encoding means 3 (for example, an entropy encoder 103 shown in fig. 1) for entropy encoding the output data of the transform means 2; non-compression encoding means 7 (for example, PCM encoder 107) for non-compression encoding the input data; multiplexed data selection means 8 (e.g., switch 121) for selecting output data of the entropy encoding means 3 or output data of the non-compression encoding means 7; and multiplexing means 10 (e.g., multiplexer 110) for multiplexing pixel bit length increase information into a bit stream, in which the pixel bit length of an image corresponding to the output data of the entropy encoding means 3 and the pixel bit length of an image corresponding to the output data of the non-compression encoding means 7 are different from each other.

In order to make the pixel bit lengths different from each other, the video encoding apparatus includes, for example, means for supplying the input image before the increase in the pixel bit length to the non-compression encoding apparatus 7. In this case, the input image whose pixel bit length is not increased is subjected to non-compression encoding (for example, PCM encoding).

Fig. 12 is a block diagram showing the main part of another video encoding apparatus according to the present invention. As shown in fig. 12, in addition to the structure shown in fig. 11, another video encoding apparatus according to the present invention includes a pixel bit length reduction means 9 (e.g., a pixel bit length reduction unit 112 shown in fig. 6) for reducing the pixel bit length based on pixel bit length increase information, wherein input data of the non-compression encoding means 7 is output data of the pixel bit length reduction means 9.

Fig. 13 is a block diagram showing the main part of another video encoding apparatus according to the present invention. As shown in fig. 13, another video encoding apparatus according to the present invention includes, in addition to the structure shown in fig. 11: a prediction device 10 (e.g., a predictor 106 shown in fig. 1) for predicting an image; inverse transform means 12 (e.g., inverse transformer/inverse quantizer 104 shown in fig. 1) for inverse-transforming the output data of transform means 2; and non-compression decoding means 13 (for example, a PCM decoder 108 shown in fig. 1) for decoding output data of the non-compression encoding means 7, wherein the non-compression decoding means 13 increases the pixel bit length of a decoded image obtained by the non-compression decoding based on at least the pixel bit length increase information.

Fig. 14 is a block diagram showing a main part of a video decoding apparatus according to the present invention. As shown in fig. 14, the video decoding apparatus according to the present invention includes: demultiplexing means 21 (for example, a demultiplexer 201 shown in fig. 4) for demultiplexing a bit stream including at least pixel bit length increase information; entropy decoding means 24 (for example, an entropy decoder 204 shown in fig. 4) for entropy decoding the transformed data of the images included in the bitstream; inverse transform means 26 (e.g., inverse transformer/inverse quantizer 206 shown in fig. 4) for inverse transforming the entropy decoded transformed data of the image; non-compression decoding means 23 (for example, a PCM decoder 203 shown in fig. 4) for non-compression decoding non-compression encoded data of an image included in the bit stream; and decoding control means 22 (e.g., a decoding controller 202 shown in fig. 4) for controlling the entropy decoding means 24 and the non-compression decoding means 23, wherein a pixel bit length of an image corresponding to input data of the entropy decoding means 24 and a pixel bit length of an image corresponding to input data of the non-compression decoding means 23 are different from each other.

Fig. 15 is a block diagram showing the main part of another video decoding apparatus according to the present invention. As shown in fig. 15, the video decoding apparatus according to the present invention includes, in addition to the structure shown in fig. 14, a prediction means 27 (e.g., a predictor 207 shown in fig. 4) for predicting an image.

As described above, the present invention provides means for making the pixel bit length of an image corresponding to entropy-encoded output data and the pixel bit length of an image corresponding to non-compression-encoded output data different from each other in video encoding based on pixel bit length increase and non-compression encoding. The invention can solve the problem that the pixel bit length increment is increased in the output data of PCM coding, enhances the operation precision of intra-frame prediction and inter-frame prediction by pixel bit length expansion, and ensures the fixed processing time for a video coding device or a video decoding device.

The above-described exemplary embodiments may be partially or completely described in the following supplementary notes, but the present invention is not limited to the following structures.

(supplementary note 1) a video encoding method comprising: transforming data obtained by increasing a pixel bit length of the input image based on the pixel bit length increase information; entropy encoding the transformed data; performing non-compression encoding on input data; selecting entropy-encoded data or non-compression-encoded data; and multiplexing the pixel bit length increase information into a bit stream, wherein a pixel bit length of an image corresponding to the entropy-encoded data and a pixel bit length of an image corresponding to the non-compression-encoded data are different from each other, and wherein an input image before the pixel bit length is increased is used as input data to be subjected to the non-compression encoding.

(supplementary note 2) a video encoding method comprising: transforming data obtained by increasing a pixel bit length of the input image based on the pixel bit length increase information; entropy encoding the transformed data; performing non-compression encoding on input data; selecting entropy-encoded data or non-compression-encoded data; and multiplexing pixel bit length increase information into the bitstream, wherein a pixel bit length of an image corresponding to the entropy-encoded data and a pixel bit length of an image corresponding to the non-compression-encoded data are different from each other, wherein the video encoding method includes reducing the pixel bit length of the data whose pixel bit length has been increased based on the pixel bit length increase information, and wherein the data whose pixel bit length has been reduced is used as input data to be subjected to the non-compression encoding.

(supplementary note 3) a video encoding method comprising: transforming data obtained by increasing a pixel bit length of the input image based on the pixel bit length increase information; entropy encoding the transformed data; performing non-compression encoding on input data; selecting entropy-encoded data or non-compression-encoded data; and multiplexing the pixel bit length increase information into a bitstream, wherein a pixel bit length of an image corresponding to the entropy-encoded data and a pixel bit length of an image corresponding to the data to be non-compression-encoded are different from each other, and wherein the video encoding method includes: performing inverse transformation on the transformed data; decoding the non-compression encoded data; and increasing, at the time of decoding, a pixel bit length of a decoded image obtained by the non-compression decoding based on at least the pixel bit length increase information.

(supplementary note 4) a video decoding method comprising: demultiplexing a bit stream including at least pixel bit length increase information; entropy-decoding transformed data of an image included in the bitstream; inverse transforming the entropy-decoded transformed data of the image; and non-compression decoding non-compression encoded data of an image included in the bitstream, wherein a pixel bit length of an image corresponding to the transformed data of the image included in the bitstream and a pixel bit length of an image corresponding to the non-compression encoded data of the image included in the bitstream are different from each other, and wherein the video decoding method includes increasing the pixel bit length of a decoded image obtained by the non-compression decoding based on at least the pixel bit length increase information when the non-compression decoding is performed.

(supplementary note 5) a video decoding method comprising: demultiplexing a bit stream including at least pixel bit length increase information; entropy-decoding transformed data of an image included in the bitstream; inverse transforming the entropy-decoded transformed data of the image; and non-compression decoding non-compression encoded data of an image included in the bitstream, wherein a pixel bit length of an image corresponding to the transformed data of the image included in the bitstream and a pixel bit length of an image corresponding to the non-compression encoded data of the image included in the bitstream are different from each other, and wherein the video decoding method includes performing prediction processing for a prediction image.

(supplementary note 6) a video encoding program that causes a computer to execute: a process for transforming data obtained by increasing the pixel bit length of the input image based on the pixel bit length increase information; a process for entropy-encoding the transformed data; processing for performing non-compression encoding on input data; a process for selecting entropy-encoded data or non-compression-encoded data; and a process for multiplexing the pixel bit length increase information into a bit stream, wherein a pixel bit length of an image corresponding to the entropy-encoded data and a pixel bit length of an image corresponding to the non-compression-encoded data are different from each other, and wherein an input image before the pixel bit length is increased is used as input data to be subjected to the non-compression encoding.

(supplementary note 7) a video encoding program causing a computer to execute: a process for transforming data obtained by increasing the pixel bit length of the input image based on the pixel bit length increase information; a process for entropy-encoding the transformed data; processing for performing non-compression encoding on input data; a process for selecting entropy-encoded data or non-compression-encoded data; and a process for multiplexing pixel bit length increase information into a bit stream, wherein a pixel bit length of an image corresponding to the entropy-encoded data and a pixel bit length of an image corresponding to the non-compression-encoded data are different from each other, and wherein the video encoding program causes the computer to execute a process for reducing the pixel bit length of the data whose pixel bit length has been increased based on the pixel bit length increase information, and use the data whose pixel bit length has been reduced as input data to be subjected to the non-compression encoding.

(supplementary note 8) a video encoding program that causes a computer to execute: a process for transforming data obtained by increasing the pixel bit length of the input image based on the pixel bit length increase information; a process for entropy-encoding the transformed data; processing for performing non-compression encoding on input data; a process for selecting entropy-encoded data or non-compression-encoded data; and a process for multiplexing the pixel bit length increase information into a bit stream, wherein a pixel bit length of an image corresponding to the entropy-encoded data and a pixel bit length of an image corresponding to the non-compression-encoded data are different from each other, and wherein the video encoding program causes a computer to execute: a process for performing inverse transformation on the transformed data; a process for decoding the non-compression encoded data; and a process for increasing the pixel bit length of a decoded image obtained by the non-compression decoding based on at least the pixel bit length increase information at the time of decoding.

(supplementary note 9) a video decoding program that causes a computer to execute: a process for demultiplexing a bit stream including at least pixel bit length increase information; a process for entropy-decoding transformed data of an image included in the bitstream; a process for inverse-transforming the entropy-decoded transformed data of the image; and processing for non-compression decoding non-compression encoded data of an image included in the bitstream, wherein a pixel bit length of an image corresponding to the transformed data of the image included in the bitstream and a pixel bit length of an image corresponding to the non-compression encoded data of the image included in the bitstream are different from each other, and wherein the video decoding program causes the computer to execute processing for increasing the pixel bit length of a decoded image obtained by the non-compression decoding based on at least the pixel bit length increase information when the non-compression decoding is performed.

(supplementary note 10) a video decoding program that causes a computer to execute: a process for demultiplexing a bit stream including at least pixel bit length increase information; a process for entropy-decoding transformed data of an image included in the bitstream; a process for inverse-transforming the entropy-decoded transformed data of the image; and processing for non-compression decoding non-compression encoded data of an image included in the bitstream, wherein a pixel bit length of an image corresponding to the transformed data of the image included in the bitstream and a pixel bit length of an image corresponding to the non-compression encoded data of the image included in the bitstream are different from each other, and wherein the video decoding program causes a computer to perform prediction processing for predicting an image.

Although the present invention is described with reference to the above exemplary embodiments and examples, the present invention is not limited to the above exemplary embodiments and examples. Various changes in the structure and details of the invention may be made by those skilled in the art which will be understood to fall within the scope of the invention.

This application claims priority based on japanese patent application No.2010-159059 filed on day 13 of 2010 and japanese patent application No.2011-040530 filed on day 25 of 2011, the disclosures of which are incorporated herein in their entirety.

List of reference numerals

1: pixel bit length increasing device

2: conversion device

3: entropy coding device

7: non-compression encoding device

8: multiplexed data selection device

9: pixel bit length reduction apparatus

10 multiplexing device

11 prediction device

12 inverse transformation device

13 non-compression decoding device

21 demultiplexing device

22 decoding control device

23 non-compression decoding device

24 entropy decoding device

26 inverse transformation device

27 prediction device

101 pixel bit length increasing unit

102 transformer/quantizer

103 entropy coder

104 inverse transformer/inverse quantizer

105 buffer

106 predictor

107 PCM encoder

108 PCM decoder

109 multiplexed data selector

110 multiplexer

111 pixel bit length increasing unit

112 pixel bit length reduction unit

121 switch

122 switch

201 demultiplexer

202 decoding controller

204 entropy decoder

205 pixel bit length increasing unit

206 inverse transformer/inverse quantizer

207 predictor

208 buffer

209 pixel bit length reduction unit

221 switch

222 switch

1001 processor

1002 program memory

1003 storage medium

1004 storage medium

Claims (2)

1. A video decoding apparatus, comprising:

an extraction unit that extracts pixel bit length increase information of luminance and pixel bit length increase information of color difference from a bitstream;

an entropy decoding unit entropy-decoding transformed data of an image included in the bitstream;

a non-compression decoding unit that non-compression-decodes non-compression-encoded data of an image included in the bitstream; and

a decoding control unit that controls the entropy decoding unit and the non-compression decoding unit,

wherein a pixel bit length of an image corresponding to the input data of the non-compression decoding unit is different from a pixel bit length of an image corresponding to the input data of the entropy decoding unit, and

wherein a pixel bit length of a decoded image obtained by the non-compression decoding is increased based on the pixel bit length increase information of the luminance and the pixel bit length increase information of the color difference.

2. A video decoding method, comprising:

extracting pixel bit length increase information of luminance and pixel bit length increase information of color difference from the bitstream;

entropy-decoding transformed data of an image included in the bitstream;

non-compression decoding non-compression encoded data of an image included in the bitstream; and

controlling the entropy decoding and the non-compression decoding,

wherein a pixel bit length of an image corresponding to the non-compression decoded input data is different from a pixel bit length of an image corresponding to the entropy decoded input data, and

wherein a pixel bit length of a decoded image obtained by the non-compression decoding is increased based on the pixel bit length increase information of the luminance and the pixel bit length increase information of the color difference.