WO2012013327A1 - Signal d'erreur de prédiction quantifié pour filtre de wiener à trois entrées - Google Patents

Signal d'erreur de prédiction quantifié pour filtre de wiener à trois entrées Download PDF

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WO2012013327A1
WO2012013327A1 PCT/EP2011/003721 EP2011003721W WO2012013327A1 WO 2012013327 A1 WO2012013327 A1 WO 2012013327A1 EP 2011003721 W EP2011003721 W EP 2011003721W WO 2012013327 A1 WO2012013327 A1 WO 2012013327A1
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signal
video
prediction error
data
error signal
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PCT/EP2011/003721
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Matthias Narroschke
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Panasonic Corporation
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/80—Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation
    • H04N19/82—Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation involving filtering within a prediction loop
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/117—Filters, e.g. for pre-processing or post-processing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/124—Quantisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/136—Incoming video signal characteristics or properties
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/146—Data rate or code amount at the encoder output
    • H04N19/147—Data rate or code amount at the encoder output according to rate distortion criteria
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding

Definitions

  • the present invention relates to a picture encoding/decoding method, apparatus and a program for executing these methods in software.
  • the present invention relates to a method for reducing quantization errors of the quantized prediction error samples prior to the use of them in a subsequent processing unit such as a Three-Input-Wiener-Filter.
  • Hybrid video coding methods typically combine several different lossless and lossy compression schemes in order to achieve the desired compression gain.
  • Hybrid video coding is also the basis for ITU-T standards (H.26x standards such as H.261 , H.263) as well as ISO/I EC standards (MPEG-X standards such as MPEG-1 , MPEG-2, and MPEG-4).
  • ITU-T standards H.26x standards such as H.261 , H.263
  • ISO/I EC standards MPEG-X standards such as MPEG-1 , MPEG-2, and MPEG-4.
  • AVC H.264/MPEG-4 advanced video coding
  • JVT joint video team
  • ISO/IEC MPEG groups ISO/IEC MPEG groups.
  • JCT-VC Joint Collaborative Team on Video Coding
  • HEVC High-Efficiency Video Coding
  • Standardized hybrid video coders are used to code image signals, each being Pulse Coded Modulation (PCM) coded with M bits per color component.
  • the color format may be e.g. YUV or RGB, but it is not limited thereto.
  • the number M is typically also called bit depth. This bit depth M is often 8 bits/sample.
  • There the sample refers to a sample of a colour component such as Y, U, V or R, G, B. In certain situations, it may be different, e.g. 10 bits/sample or 12 bits/sample.
  • a video signal input to an encoder is a sequence of images called frames, each frame being a two-dimensional matrix of pixels.
  • All the above-mentioned standards based on hybrid video coding include subdividing each individual video frame into smaller blocks consisting of a plurality of pixels.
  • the size of the blocks may vary, for instance, in accordance with the content of the image.
  • the way of coding may be typically varied on a per block basis.
  • the largest possible size for such a block, for instance in HEVC, is 64 x 64 pixels. It is then called the largest coding unit (LCU).
  • a macroblock (usually denoting a block of 16 x 16 pixels) was the basic image element, for which the encoding is performed, with a possibility to further divide it in smaller subblocks to which some of the coding/decoding steps were applied.
  • the encoding steps of a hybrid video coding include a spatial and/or a temporal prediction. Accordingly, each block to be encoded is first predicted using either the blocks in its spatial neighborhood or blocks from its temporal neighborhood, i.e. from previously encoded video frames. A block of differences between the block to be encoded and its prediction, also called block of prediction residuals, is then calculated.
  • Another encoding step is a transformation of a block of residuals from the spatial (pixel) domain into a frequency domain. The transformation aims at reducing the correlation of the input block.
  • Further encoding step is quantization of the transform coefficients. In this step the actual lossy (irreversible) compression takes place.
  • the compressed transform coefficient values are further compacted (losslessly compressed) by means of an entropy coding.
  • side information necessary for reconstruction of the encoded video signal is encoded and provided together with the encoded video signal. This is for example information about the spatial and/or temporal prediction, amount of quantization, etc.
  • Figure 1 is an example of a typical H.264/MPEG-4 AVC and/or HEVC video encoder 100.
  • a subtractor 105 first determines differences e between a current block to be encoded of an input video image (original signal s) and a corresponding prediction block s, which is used as a prediction of the current block to be encoded.
  • the prediction signal may be obtained by a temporal or by a spatial prediction 180. The type of prediction can be varied on a per frame basis or on a per block basis. Blocks and/or frames predicted using temporal prediction are called “inter"-encoded and blocks and/or frames predicted using spatial prediction are called "intra"-encoded. Prediction signal using temporal prediction is derived from the previously encoded images, which are stored in a memory.
  • the prediction signal using spatial prediction is derived from the values of boundary pixels in the neighboring blocks, which have been previously encoded, decoded, and stored in the memory.
  • the difference e between the input signal and the prediction signal, denoted prediction error or residual, is transformed 110 resulting in coefficients 121 , which are quantized.
  • Entropy encoder may then be applied to the quantized coefficients in order to further reduce the amount of data to be stored and/or transmitted in a lossless way. This is mainly achieved by applying a code with code words of variable length wherein the length of a code word is chosen based on the probability of its occurrence. From the input signal s , a prediction signal s is subtracted resulting in the prediction error e .
  • the prediction signal usually has also an accuracy of M bit/sample. This accuracy is same as the one of the input signal to be coded. Due to the subtraction, the prediction error signal has an accuracy or bit depth of M+1 bit/sample.
  • This prediction error is transformed into the frequency domain using a discrete cosine transformation (DCT) or a similar transform, e.g. an integer DCT or a Karhunen-Loeve Transformation (KLT). Any other transform may also be used.
  • DCT discrete cosine transformation
  • KLT Karhunen-Loeve Transformation
  • Any other transform may also be used.
  • the resulting coefficients c are quantized 120 resulting in quantized coefficients c . These quantized coefficients 121 are coded and transmitted.
  • the differences e between the current input signal and the prediction signal are transformed 1 10 and quantized 120, resulting in the quantized coefficients.
  • lower frequency components are usually more important for image quality then high frequency components so that more bits can be spent for coding the low frequency components than the high frequency components.
  • the two-dimensional matrix of quantized coefficients is converted into a one-dimensional array. Typically, this conversion is performed by a so- called zig-zag scanning, which starts with the DC-coefficient in the upper left corner of the two-dimensional array and scans the two-dimensional array in a predetermined sequence ending with an AC coefficient in the lower right corner.
  • the zig-zag scanning results in an array where usually the last values are zero. This allows for efficient encoding using run-length codes as a part of/before the actual entropy coding.
  • a decoding unit is incorporated for obtaining a decoded (reconstructed) video signal s'.
  • the quantized coefficients c' are inverse transformed 130.
  • the resulting quantized prediction error samples e are added 140 to the prediction signal s for reconstruction.
  • the so obtained prediction error signal e' differs from the original prediction error signal due to the quantization error, called also quantization noise.
  • the reconstructed signal is denoted as s' .
  • the prediction signal s is obtained based on the encoded and subsequently decoded video signal which is known at both sides the encoder and the decoder.
  • a deblocking filter 160 is applied to every reconstructed image block.
  • the deblocking filter is applied to the reconstructed signal s'.
  • the deblocking filter of H.264/MPEG-4 AVC has the capability of local adaptation.
  • a strong (narrow-band) low pass filter is applied, whereas for a low degree of blocking noise, a weaker (broad-band) low pass filter is applied.
  • the strength of the low pass filter is determined by the prediction signal s and by the quantized prediction error signal e'.
  • Deblocking filter generally smoothes the block edges leading to an improved subjective quality of the decoded images. Moreover, since the filtered part of an image is used for the motion compensated prediction of further images, the filtering also reduces the prediction errors, and thus enables improvement of coding efficiency.
  • This signal is generally further deblocked resulting in the signal s" of also M bits/sample.
  • JCTVC-B1 13 "Codeword Restriction for Improved Coding Efficiency", Contribution to JCT-VC meeting Geneva, July 2010. A more precise clipping to some specific maximum and minimum values is also beneficial.
  • This invention can be applied also in the case, JCTVC-B113 is used.
  • an adaptive loop filter 170 may be applied to the image including the already deblocked signal s". Whereas the deblocking filter improves the subjective quality the adaptive loop filter (ALF) aims at improving the pixel-wise fidelity ("objective" quality).
  • the adaptive loop filter is used to compensate image distortion caused by the compression.
  • the adaptive loop filter is a Wiener filter with filter coefficients determined such that the mean square error (MSE) between the reconstructed s' and source images s is minimized.
  • MSE mean square error
  • the coefficients of adaptive loop filter may be calculated and transmitted on a frame basis.
  • the adaptive loop filter can be applied to the entire frame (image of the video sequence) or to local areas (blocks).
  • An additional side information indicating which areas are to be filtered may be transmitted (block-based, frame-based or quadtree-based).
  • EP2141927 A1 denoted as “reference 1” in this document
  • JCTVC-A114 denoted as “reference 2” in this document
  • Video coding technology proposal by France Telecom, NTT, NTT DoCoMo, Panasonic and Technicolor Contribution to JCT-VC meeting Dresden, April 2010, it is beneficial to apply a system of three adaptive filters to reconstruct a signal s .
  • This system of three adaptive filters is also denoted as Three-lnput-Wiener-Filter. It operates as described by the following formula:
  • a first filter with the filter coefficients c operates on the quantized prediction error samples e"
  • a second filter with the coefficients c m operates on the samples of the deblocked signal s m m
  • a third filter with the coefficients c n operates on the samples of the prediction signal s n .
  • the corresponding filter coefficients are c, , c m , and c n .
  • inter-encoded blocks require also storing the previously encoded and subsequently decoded portions of image(s) in a reference frame buffer.
  • An inter- encoded block is predicted 180 by employing motion compensated prediction.
  • a best- matching block is found for the current block within the previously encoded and decoded video frames by a motion estimator.
  • the best-matching block then becomes a prediction signal and the relative displacement (motion) between the current block and its best match is then signalized as motion data in the form of three-dimensional motion vectors within the side information provided together with the encoded video data.
  • the three dimensions consist of two spatial dimensions and one temporal dimension.
  • motion vectors may be determined with a spatial sub-pixel resolution e.g.
  • a motion vector with spatial sub-pixel resolution may point to a spatial position within an already decoded frame where no real pixel value is available, i.e. a sub-pixel position.
  • spatial interpolation of such pixel values is needed in order to perform motion compensated prediction. This may be achieved by an interpolation filter (in Figure 1 integrated within Prediction block 180).
  • the H.264/MPEG-4 H.264/MPEG-4 AVC as well as HEVC includes two functional layers, a Video Coding Layer (VCL) and a Network Abstraction Layer (NAL).
  • VCL Video Coding Layer
  • NAL Network Abstraction Layer
  • the VCL provides the encoding functionality as briefly described above.
  • the NAL encapsulates information elements into standardized units called NAL units according to their further application such as transmission over a channel or storing in storage.
  • the information elements are, for instance, the encoded prediction error signal or other information necessary for the decoding of the video signal such as type of prediction, quantization parameter, motion vectors, etc.
  • VCL NAL units containing the compressed video data and the related information, as well as non-VCL units encapsulating additional data such as parameter set relating to an entire video sequence, or a Supplemental Enhancement Information (SEI) providing additional information that can be used to improve the decoding performance.
  • SEI Supplemental Enhancement Information
  • the corresponding hybrid decoder is shown in Figure 2. This decoder corresponds to the internal decoder included in the hybrid encoder shown in Figure 1.
  • Figure 2 illustrates an example decoder 200 according to the H.264/MPEG-4 AVC or HEVC video coding standard.
  • the encoded video signal (input signal to the decoder) may first pass to an entropy decoder, which decodes the quantized coefficients, the information elements necessary for decoding such as motion data, mode of prediction etc.
  • the quantized coefficients are inversely scanned in order to obtain a two-dimensional matrix, which is then fed to inverse quantization and inverse transformation 230.
  • a decoded (quantized) prediction error signal e' is obtained, which corresponds to the differences obtained by subtracting the prediction signal from the signal input to the encoder in the case no quantization noise is introduced and no error occurred.
  • the prediction signal is obtained from either a temporal or a spatial prediction 280.
  • the decoded information elements usually further include the information necessary for the prediction such as prediction type in the case of intra-prediction and motion data in the case of motion compensated prediction.
  • the quantized prediction error signal in the spatial domain is then added with an adder 240 to the prediction signal obtained either from the motion compensated prediction or intra-frame prediction 280.
  • the reconstructed image s' may be passed through a deblocking filter 260 and an adaptive loop filter 270 and the resulting decoded signal may be stored in the memory to be applied for temporal or spatial prediction of the following blocks/images.
  • the 3-lnput-Wiener-Filter 270 requires the quantized prediction error signal as one of the three input signals. In certain situations, the 3-lnput-Wiener-Filter may only operate on a subset of these signals. In the references 1 , and 2, the quantized prediction error signal e is clipped exploiting the knowledge that it can not exceed M+1 bit/sample. The resulting signal is e
  • the resulting signal s" is associated with a lower quantization error than the signal s' prior the clipping.
  • the result is 10, which is unchanged compared to prior the clipping.
  • the quantization error is only reduced for the signal s' , but not for the signal e .
  • the coding efficiency of the two reference methods is limited and furthermore, the computational expense is high due to the required clipping operations. Both are not desired.
  • a method for correcting the quantized prediction error signal prior the use of it in a subsequent processing unit comprising: reconstructing a signal by adding the quantized prediction error signal to the prediction signal, clipping the reconstructed signal, and correcting the quantized prediction error signal based on the clipped reconstructed signal.
  • an apparatus for correcting the quantized prediction error signal prior the use of it in a subsequent processing unit comprising: a reconstruction unit for reconstructing a signal by adding the quantized prediction error signal to the prediction signal, a clipping unit for clipping the reconstructed signal, and a correction unit for correcting the quantized prediction error signal based on the clipped reconstructed signal.
  • the signal may be a digital image and or video signal.
  • the signal may be subdivided into frames (pictures), in which a frame is further subdivided into blocks of pixels.
  • the quantized prediction error signal, prediction signal and the reconstructed signal may be processed by the steps of clipping und correcting block-wisely.
  • the subsequent processing may be also preformed block-wisely.
  • the present invention is not limited thereto and the subsequent processing may also be applied to the entire frame.
  • the correction of the quantized prediction error signal is performed by subtracting the reconstructed signal from the clipped reconstructed signal and adding this result to the quantized prediction error signal.
  • the correction of the quantized prediction error signal may be performed by subtracting the prediction signal from the clipped reconstructed signal.
  • other possibilities are also possible.
  • the subsequent processing is an adaptive filtering applied to the reconstructed signal.
  • the filter may a Wiener filter with three inputs: clipped reconstructed signal, corrected prediction error signal, and prediction signal.
  • the internal bit-depth is decreased after the adaptive filtering; and the filtered signal with decreased bit depth is stored into a memory. This enables reducing the memory requirements.
  • a method is provided for encoding a digital image signal block-wise, including processing a block of the digital image with the method as described above.
  • a method is provided for decoding a digital image signal block-wise, including processing a block of the digital image with the method described above.
  • a computer program product comprising a computer-readable medium having a computer-readable program code embodied thereon, the program code being adapted to carry out the method described above for correcting the quantized prediction error.
  • an encoder for encoding a digital image signal block-wisely, including the apparatus for correcting the quantized prediction error signal as described above.
  • a decoder is provided for decoding a digital image signal block-wisely, including the apparatus for correcting the quantized prediction error signal as described above.
  • Figure 1 is a block diagram illustrating an example of a hybrid video encoder
  • Figure 2 is a block diagram illustrating an example of a hybrid video decoder
  • Figure 3 is a block diagram illustrating an example of a hybrid video decoder with a general processing unit
  • Figure 4 is a block diagram illustrating an example of a hybrid video decoder with a
  • Figure 5 is a block diagram illustrating an example of a hybrid video encoder in accordance with an embodiment of the present invention
  • Figure 6 is a block diagram illustrating an example of a hybrid video decoder in accordance with an embodiment of the present invention
  • Figure 7 is a flow diagram illustrating an example of method steps according to an embodiment of the present invention
  • Figure 8 is a block diagram illustrating an example of a hybrid video encoder according to a embodiment of the present invention
  • Figure 9 is a block diagram illustrating an example of a hybrid video decoder with a general processing unit in accordance with an embodiment of the present invention
  • Figure 10 is a block diagram illustrating an example of a hybrid video decoder with a
  • Figure 1 1 is a flow diagram illustrating steps of a method according to an embodiment of the present invention
  • Figure 12 is a block diagram illustrating an example of functional blocks of an encoding apparatus employed when the quantized prediction error is zero in accordance with an embodiment of the present invention
  • Figure 13 is a block diagram illustrating an example of functional blocks of a decoding apparatus employed when the quantized prediction error is zero in accordance with an embodiment of the present invention
  • Figure 14 is a block diagram illustrating a hybrid decoder in accordance with an embodiment of the present invention, applying an internal bit-depth increase
  • Figure 15 is a block diagram illustrating a hybrid decoder in accordance with another embodiment of the present invention, applying an internal bit-depth increase
  • Figure 16 is a schematic drawing illustrating an overall configuration of a content providing system for implementing content distribution services
  • Figure 17 is a schematic drawing illustrating an overall configuration of a digital broadcasting system
  • Figure 18 is a block diagram illustrating an example of a configuration of a television
  • Figure 19 is a block diagram illustrating an example of a configuration of an information reproducing/recording unit that reads and writes information from or on a recording medium that is an optical disk;
  • Figure 20 is a schematic drawing showing an example of a configuration of a recording medium that is an optical disk
  • Figure 21 A is a schematic drawing illustrating an example of a cellular phone; is a block diagram showing an example of a configuration of the cellular phone; is a schematic drawing showing a structure of multiplexed data; is a drawing schematically illustrating how each of the streams is multiplexed in multiplexed data; is a schematic drawing illustrating how a video stream is stored in a stream of PES packets in more detail; is a schematic drawing showing a structure of TS packets and source packets in the multiplexed data; is a schematic drawing showing a data structure of a PMT; is a schematic drawing showing an internal structure of multiplexed data information; is a schematic drawing showing an internal structure of stream attribute information; is a schematic drawing showing steps for identifying video data; is a schematic block diagram illustrating an example of a configuration of an integrated circuit for implementing the video coding method and the video decoding method according to each of embodiments; is a schematic drawing showing a configuration for switching between driving frequencies; is a schematic drawing showing steps for
  • Figure 34A is a schematic drawing showing an example of a configuration for sharing a module of a signal processing unit
  • Figure 34B is a schematic drawing showing another example of a configuration for sharing a module of a signal processing unit.
  • a decoder is shown using a general processing unit 370, which may be different in internal functionality from the specific 3-lnput-Wiener-Filter 270 shown in Figure 2, but accepting also at least the quantized prediction error signal as one input signal.
  • the processing unit 370 may implement any kind of processing such as filtering, offsetting, or any modification of an input signal.
  • the processing unit 370 may have 1 or more inputs, meaning that it may process one or more input signals.
  • a specific problem underlying the prior art is that a correction of the signal by clipping is not achieved for the quantized prediction error e as already shown above.
  • the present invention provides approach to correcting the quantized prediction error based on the clipped reconstructed signal.
  • the effect of the invention is a correction also of the quantized prediction error e prior it's use in a subsequent processing unit 370 such as the 3-lnput-Wiener-Filter 170, 270.
  • This increases the coding efficiency due to a more precise prediction error signal.
  • less quantization errors are superposed to the quantized prediction error e .
  • the image encoding apparatus consists of a block-based hybrid encoder according to Fig. 5 capable of performing the additional operations compared to Fig. 1 as follows:
  • a correction value s' - s which is the reconstructed value after clipping minus the reconstructed value before the clipping, is calculated and added to the quantized prediction error signal e resulting in the corrected quantized prediction error signal e . This may be performed by the subtractor 510 and the adder 520.
  • This signal is clipped subsequently. This may be performed by the clipping unit 552. As a result of this operation, the quantized prediction error signal contains less quantization errors.
  • the clipped signal may be input to the processing unit 570. Other signals may be input to the processing unit 570 as well.
  • FIG. 7 A corresponding flow chart of a method according to this embodiment of the present invention is shown in Fig. 7.
  • step 710 the reconstructed signal s' is subtracted from the clipped reconstructed signal s" in order to obtain the correction value.
  • step 720 the obtained correction value is added to the quantized prediction error signal e'.
  • the resulting corrected quantized prediction error signal is in step 730 clipped and used 740 in a further processing step.
  • the image decoding apparatus comprises a block-based hybrid decoder according to Fig. 6 including the additional operations compared to Fig. 2 as follows.
  • a correction value s" - s' which is the reconstructed value after clipping minus the reconstructed value before the clipping, is calculated by a subtractor 610 and added to the quantized prediction error signal e by an adder 620, resulting in the corrected quantized prediction error signal e .
  • This signal is clipped by a clipping unit 630 subsequently. As a result of this operation, the quantized prediction error signal contains less quantization errors.
  • a corresponding flow chart is shown in Fig. 7 as described above.
  • the image encoding apparatus 800 comprises a block-based hybrid encoder according to Fig. 8 capable of performing the additional operations compared to Fig. 1 as follows.
  • the prediction signal s is subtracted from the clipped reconstructed signal s" resulting in the corrected quantized prediction error signal e . This may be performed by the subtractor 810.
  • No further clipping of e prior to the subsequent processing unit 870, such as the 3- Input-Wiener-Filter, is necessary since both, s and , have a bit depth of M and thus e is limited already to the bit depth M+1.
  • a corresponding flow chart is shown in Fig. 1 1. Compared to the references, also the computational expense is reduced in addition to the increased coding efficiency.
  • the image decoding apparatus comprises a block- based hybrid decoder according to Fig. 9 capable of performing additional operations compared to Fig. 2 as follows:
  • the prediction signal s is subtracted from the clipped reconstructed signal s" resulting in the corrected quantized prediction error signal e" .
  • This may be performed by a subtractor 910.
  • a corresponding flow chart is shown in Fig. 1 1. Compared to the references, also the computational expense is reduced in addition to the increased coding efficiency. This is due to the substitution of a clipping operation by a subtraction operation, which is associated with lower costs.
  • FIG. 10 shows the processing unit 970 being a 3-lnput-Wiener-Filter 1070, similarly as Figure 4 shows the processing unit 370 being a 3-lnput-Wiener-Filter 470. It is noted that the processing unit such as 370, 970 are not necessarily 3-lnput units. Such processing unit may have more or less inputs, for instance only the reconstructed signal or only the clipped quantized error prediction, or a combination of two inputs out of the three shown in the Figures.
  • the image decoding apparatus according to the seventh embodiment comprises a block- based hybrid decoder according to Fig. 14. In this decoder, the bit depth of the M bit/sample input video signal has been extended to M+N bit sample, e.g. by the use of a bit shift operation of N bits to the left. This may be achieved, for instance by bit-depth increasing unit 1420 located after frame memory 1450 access.
  • This extension has the benefit that internal decoding operations can be executed in a higher precision than it would be possible with the use of only M bit/sample. This is associated also with a higher coding efficiency.
  • the reference memory is still M bit/sample and the processing unit using the quantized prediction error signal as input operates in the extended bit depth. This may be facilitated by a bit-depth decreasing unit 1410 located before storing the data into the frame memory 1450.
  • the image encoding apparatus comprises a block- based hybrid encoder including an internal decoder according to Fig. 14.
  • the bit depth of the M bit/sample input video signal has been extended to M+N bit sample, e.g. by the use of a bit shift operation of N bits to the left.
  • This extension has the benefit that internal decoding operations can be executed in a higher precision than it would be possible with the use of only M bit/sample. This is associated also with a higher coding efficiency.
  • the reference memory is still M bit/sample and the processing unit using the quantized prediction error signal as input operates in the extended bit depth.
  • the image decoding apparatus comprises a block- based hybrid decoder according to Fig. 15.
  • the bit depth of the M bit/sample input video signal has been extended to M+N bit/sample. This may be performed, for instance by a bit-depth increasing unit 1530.
  • the reference memory 1550 is still M bit/sample and also the processing unit 1570 using the quantized prediction error signal as input operates in the M bit/sample.
  • the invention allows using only two bit depth decreases, performed, for instance by bit-depth decreasing units 1510 and 1520, for the three input signals of the processing unit.
  • the image decoding apparatus consists of a block- based hybrid encoder including an internal decoder according to Fig. 15.
  • the bit depth of the input video signal of M bit/sample has been extended to M+N bit/sample.
  • the reference memory is still M bit/sample and also the processing unit using the quantized prediction error signal as input operates in the bit/sample.
  • the invention allows using only two bit depth decreases for the three input signals of the processing unit.
  • the processing described in each of embodiments can be simply implemented in an independent computer system, by recording, in a recording medium, a program for implementing the configurations of the video coding method and the video decoding method described in each of embodiments.
  • the recording media may be any recording media as long as the program can be recorded, such as a magnetic disk, an optical disk, a magnetic optical disk, an IC card, and a semiconductor memory.
  • Figure 21 illustrates an overall configuration of a content providing system ex100 for implementing content distribution services.
  • the area for providing communication services is divided into cells of desired size, and base stations ex106, ex107, ex108, ex109, and ex1 10 which are fixed wireless stations are placed in each of the cells.
  • the content providing system ex100 is connected to devices, such as a computer ex1 1 1 , a personal digital assistant (PDA) ex1 12, a camera ex1 13, a cellular phone ex1 14 and a game machine ex1 15, via the Internet ex101 , an Internet service provider ex102, a telephone network ex104, as well as the base stations ex106 to ex1 10, respectively.
  • PDA personal digital assistant
  • each device may be directly connected to the telephone network ex104, rather than via the base stations ex106 to ex1 10 which are the fixed wireless stations.
  • the devices may be interconnected to each other via a short distance wireless communication and others.
  • the camera ex1 13, such as a digital video camera is capable of capturing video.
  • a camera ex1 16, such as a digital video camera is capable of capturing both still images and video.
  • the cellular phone ex1 14 may be the one that meets any of the standards such as Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Wideband-Code Division Multiple Access (W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access (HSPA).
  • GSM Global System for Mobile Communications
  • CDMA Code Division Multiple Access
  • W-CDMA Wideband-Code Division Multiple Access
  • LTE Long Term Evolution
  • HSPA High Speed Packet Access
  • the cellular phone ex1 14 may be a Personal Handyphone System (PHS).
  • PHS Personal Handyphone System
  • a streaming server ex103 is connected to the camera ex1 13 and others via the telephone network ex104 and the base station ex109, which enables distribution of images of a live show and others.
  • a content for example, video of a music live show
  • the streaming server ex103 carries out stream distribution of the transmitted content data to the clients upon their requests.
  • the clients include the computer ex1 1 1 , the PDA ex1 12, the camera ex1 13, the cellular phone ex1 14, and the game machine ex1 15 that are capable of decoding the above-mentioned coded data.
  • Each of the devices that have received the distributed data decodes and reproduces the coded data.
  • the captured data may be coded by the camera ex1 13 or the streaming server ex103 that transmits the data, or the coding processes may be shared between the camera ex1 13 and the streaming server ex103.
  • the distributed data may be decoded by the clients or the streaming server ex103, or the decoding processes may be shared between the clients and the streaming server ex103.
  • the data of the still images and video captured by not only the camera ex1 13 but also the camera ex1 16 may be transmitted to the streaming server ex103 through the computer ex1 1 1.
  • the coding processes may be performed by the camera ex1 16, the computer ex1 1 1 , or the streaming server ex103, or shared among them.
  • the coding and decoding processes may be performed by an LSI ex500 generally included in each of the computer ex1 1 1 and the devices.
  • the LSI ex500 may be configured of a single chip or a plurality of chips.
  • Software for coding and decoding video may be integrated into some type of a recording medium (such as a CD-ROM, a flexible disk, and a hard disk) that is readable by the computer ex1 1 1 and others, and the coding and decoding processes may be performed using the software.
  • a recording medium such as a CD-ROM, a flexible disk, and a hard disk
  • the coding and decoding processes may be performed using the software.
  • the cellular phone ex1 14 is equipped with a camera, the image data obtained by the camera may be transmitted.
  • the video data is data coded by the LSI ex500 included in the cellular phone ex1 14.
  • the streaming server ex103 may be composed of servers and computers, and may decentralize data and process the decentralized data, record, or distribute data.
  • the clients may receive and reproduce the coded data in the content providing system ex100.
  • the clients can receive and decode information transmitted by the user, and reproduce the decoded data in real time in the content providing system ex100, so that the user who does not have any particular right and equipment can implement personal broadcasting.
  • a broadcast station ex201 communicates or transmits, via radio waves to a broadcast satellite ex202, multiplexed data obtained by multiplexing audio data and others onto video data.
  • the video data is data coded by the video coding method described in each of embodiments.
  • the broadcast satellite ex202 Upon receipt of the multiplexed data, the broadcast satellite ex202 transmits radio waves for broadcasting. Then, a home-use antenna ex204 with a satellite broadcast reception function receives the radio waves.
  • a device such as a television (receiver) ex300 and a set top box (STB) ex217 decodes the received multiplexed data, and reproduces the decoded data.
  • a device such as a television (receiver) ex300 and a set top box (STB) ex217 decodes the received multiplexed data, and reproduces the decoded data.
  • STB set top box
  • a reader/recorder ex218 (i) reads and decodes the multiplexed data recorded on a recording media ex215, such as a DVD and a BD, or (i) codes video signals in the recording medium ex215, and in some cases, writes data obtained by multiplexing an audio signal on the coded data.
  • the reader/recorder ex218 can include the video decoding apparatus or the video coding apparatus as shown in each of embodiments. In this case, the reproduced video signals are displayed on the monitor ex219, and can be reproduced by another device or system using the recording medium ex215 on which the multiplexed data is recorded.
  • FIG. 23 illustrates the television (receiver) ex300 that uses the video coding method and the video decoding method described in each of embodiments.
  • the television ex300 includes: a tuner ex301 that obtains or provides multiplexed data obtained by multiplexing audio data onto video data, through the antenna ex204 or the cable ex203, etc.
  • a modulation/demodulation unit ex302 that demodulates the received multiplexed data or modulates data into multiplexed data to be supplied outside; and a multiplexing/demultiplexing unit ex303 that demultiplexes the modulated multiplexed data into video data and audio data, or multiplexes video data and audio data coded by a signal processing unit ex306 into data.
  • the television ex300 further includes: a signal processing unit ex306 including an audio signal processing unit ex304 and a video signal processing unit ex305 that decode audio data and video data and code audio data and video data, respectively; and an output unit ex309 including a speaker ex307 that provides the decoded audio signal, and a display unit ex308 that displays the decoded video signal, such as a display.
  • the television ex300 includes an interface unit ex317 including an operation input unit ex312 that receives an input of a user operation.
  • the television ex300 includes a control unit ex310 that controls overall each constituent element of the television ex300, and a power supply circuit unit ex31 1 that supplies power to each of the elements.
  • the interface unit ex317 may include: a bridge ex313 that is connected to an external device, such as the reader/recorder ex218; a slot unit ex314 for enabling attachment of the recording medium ex216, such as an SD card; a driver ex315 to be connected to an external recording medium, such as a hard disk; and a modem ex316 to be connected to a telephone network.
  • the recording medium ex216 can electrically record information using a non-volatile/volatile semiconductor memory element for storage.
  • the constituent elements of the television ex300 are connected to each other through a synchronous bus.
  • the television ex300 decodes multiplexed data obtained from outside through the antenna ex204 and others and reproduces the decoded data
  • the multiplexing/demultiplexing unit ex303 demultiplexes the multiplexed data demodulated by the modulation/demodulation unit ex302, under control of the control unit ex310 including a CPU.
  • the audio signal processing unit ex304 decodes the demultiplexed audio data
  • the video signal processing unit ex305 decodes the demultiplexed video data, using the decoding method described in each of embodiments, in the television ex300.
  • the output unit ex309 provides the decoded video signal and audio signal outside, respectively.
  • the signals may be temporarily stored in buffers ex318 and ex319, and others so that the signals are reproduced in synchronization with each other.
  • the television ex300 may read multiplexed data not through a broadcast and others but from the recording media ex215 and ex216, such as a magnetic disk, an optical disk, and a SD card.
  • the recording media ex215 and ex216 such as a magnetic disk, an optical disk, and a SD card.
  • the audio signal processing unit ex304 codes an audio signal
  • the video signal processing unit ex305 codes a video signal, under control of the control unit ex310 using the coding method described in each of embodiments.
  • the multiplexing/demultiplexing unit ex303 multiplexes the coded video signal and audio signal, and provides the resulting signal outside.
  • the signals may be temporarily stored in the buffers ex320 and ex321 , and others so that the signals are reproduced in synchronization with each other.
  • the buffers ex318, ex319, ex320, and ex321 may be plural as illustrated, or at least one buffer may be shared in the television ex300. Furthermore, data may be stored in a buffer so that the system overflow and underflow may be avoided between the modulation/demodulation unit ex302 and the multiplexing/demultiplexing unit ex303, for example.
  • the television ex300 may include a configuration for receiving an AV input from a microphone or a camera other than the configuration for obtaining audio and video data from a broadcast or a recording medium, and may code the obtained data.
  • the television ex300 can code, multiplex, and provide outside data in the description, it may be capable of only receiving, decoding, and providing outside data but not the coding, multiplexing, and providing outside data.
  • Figure 24 illustrates a configuration of an information reproducing/recording unit ex400 when data is read or written from or on an optical disk.
  • the information reproducing/recording unit ex400 includes constituent elements ex401 , ex402, ex403, ex404, ex405, ex406, and ex407 to be described hereinafter.
  • the optical head ex401 irradiates a laser spot in a recording surface of the recording medium ex215 that is an optical disk to write information, and detects reflected light from the recording surface of the recording medium ex215 to read the information.
  • the modulation recording unit ex402 electrically drives a semiconductor laser included in the optical head ex401 , and modulates the laser light according to recorded data.
  • the reproduction demodulating unit ex403 amplifies a reproduction signal obtained by electrically detecting the reflected light from the recording surface using a photo detector included in the optical head ex401 , and demodulates the reproduction signal by separating a signal component recorded on the recording medium ex215 to reproduce the necessary information.
  • the buffer ex404 temporarily holds the information to be recorded on the recording medium ex215 and the information reproduced from the recording medium ex215.
  • the disk motor ex405 rotates the recording medium ex215.
  • the servo control unit ex406 moves the optical head ex401 to a predetermined information track while controlling the rotation drive of the disk motor ex405 so as to follow the laser spot.
  • the system control unit ex407 controls overall the information reproducing/recording unit ex400.
  • the reading and writing processes can be implemented by the system control unit ex407 using various information stored in the buffer ex404 and generating and adding new information as necessary, and by the modulation recording unit ex402, the reproduction demodulating unit ex403, and the servo control unit ex406 that record and reproduce information through the optical head ex401 while being operated in a coordinated manner.
  • the system control unit ex407 includes, for example, a microprocessor, and executes processing by causing a computer to execute a program for read and write.
  • the optical head ex401 may perform high-density recording using near field light.
  • Figure 25 illustrates the recording medium ex215 that is the optical disk.
  • an information track ex230 records, in advance, address information indicating an absolute position on the disk according to change in a shape of the guide grooves.
  • the address information includes information for determining positions of recording blocks ex231 that are a unit for recording data. Reproducing the information track ex230 and reading the address information in an apparatus that records and reproduces data can lead to determination of the positions of the recording blocks.
  • the recording medium ex215 includes a data recording area ex233, an inner circumference area ex232, and an outer circumference area ex234.
  • the data recording area ex233 is an area for use in recording the user data.
  • the inner circumference area ex232 and the outer circumference area ex234 that are inside and outside of the data recording area ex233, respectively are for specific use except for recording the user data.
  • the information reproducing/recording unit 400 reads and writes coded audio, coded video data, or multiplexed data obtained by multiplexing the coded audio and video data, from and on the data recording area ex233 of the recording medium ex215.
  • optical disk having a layer such as a DVD and a BD
  • the optical disk is not limited to such, and may be an optical disk having a multilayer structure and capable of being recorded on a part other than the surface.
  • the optical disk may have a structure for multidimensional recording/reproduction, such as recording of information using light of colors with different wavelengths in the same portion of the optical disk and for recording information having different layers from various angles.
  • a car ex210 having an antenna ex205 can receive data from the satellite ex202 and others, and reproduce video on a display device such as a car navigation system ex211 set in the car ex210, in the digital broadcasting system ex200.
  • a configuration of the car navigation system ex211 will be a configuration, for example, including a GPS receiving unit from the configuration illustrated in Figure 23. The same will be true for the configuration of the computer ex111 , the cellular phone ex114, and others.
  • Figure 26A illustrates the cellular phone ex114 that uses the video coding method and the video decoding method described in embodiments.
  • the cellular phone ex114 includes: an antenna ex350 for transmitting and receiving radio waves through the base station ex110; a camera unit ex365 capable of capturing moving and still images; and a display unit ex358 such as a liquid crystal display for displaying the data such as decoded video captured by the camera unit ex365 or received by the antenna ex350.
  • the cellular phone ex114 further includes: a main body unit including an operation key unit ex366; an audio output unit ex357 such as a speaker for output of audio; an audio input unit ex356 such as a microphone for input of audio; a memory unit ex367 for storing captured video or still pictures, recorded audio, coded or decoded data of the received video, the still pictures, e- mails, or others; and a slot unit ex364 that is an interface unit for a recording medium that stores data in the same manner as the memory unit ex367.
  • a main body unit including an operation key unit ex366; an audio output unit ex357 such as a speaker for output of audio; an audio input unit ex356 such as a microphone for input of audio; a memory unit ex367 for storing captured video or still pictures, recorded audio, coded or decoded data of the received video, the still pictures, e- mails, or others; and a slot unit ex364 that is an interface unit for a recording medium that stores data in the same manner as
  • a main control unit ex360 designed to control overall each unit of the main body including the display unit ex358 as well as the operation key unit ex366 is connected mutually, via a synchronous bus ex370, to a power supply circuit unit ex361 , an operation input control unit ex362, a video signal processing unit ex355, a camera interface unit ex363, a liquid crystal display (LCD) control unit ex359, a modulation/demodulation unit ex352, a multiplexing/demultiplexing unit ex353, an audio signal processing unit ex354, the slot unit ex364, and the memory unit ex367.
  • a power supply circuit unit ex361 an operation input control unit ex362
  • a video signal processing unit ex355 a camera interface unit ex363, a liquid crystal display (LCD) control unit ex359
  • a modulation/demodulation unit ex352 a multiplexing/demultiplexing unit ex353, an audio signal processing unit ex354, the slot unit ex364, and the memory unit ex367.
  • the power supply circuit unit ex361 supplies the respective units with power from a battery pack so as to activate the cell phone ex1 14.
  • the audio signal processing unit ex354 converts the audio signals collected by the audio input unit ex356 in voice conversation mode into digital audio signals under the control of the main control unit ex360 including a CPU, ROM, and RAM. Then, the modulation/demodulation unit ex352 performs spread spectrum processing on the digital audio signals, and the transmitting and receiving unit ex351 performs digital-to- analog conversion and frequency conversion on the data, so as to transmit the resulting data via the antenna ex350.
  • the transmitting and receiving unit ex351 amplifies the data received by the antenna ex350 in voice conversation mode and performs frequency conversion and the analog-to-digital conversion on the data. Then, the modulation/demodulation unit ex352 performs inverse spread spectrum processing on the data, and the audio signal processing unit ex354 converts it into analog audio signals, so as to output them via the audio output unit ex356. Furthermore, when an e-mail in data communication mode is transmitted, text data of the e- mail inputted by operating the operation key unit ex366 and others of the main body is sent out to the main control unit ex360 via the operation input control unit ex362.
  • the main control unit ex360 causes the modulation/demodulation unit ex352 to perform spread spectrum processing on the text data, and the transmitting and receiving unit ex351 performs the digital-to-analog conversion and the frequency conversion on the resulting data to transmit the data to the base station ex1 10 via the antenna ex350.
  • processing that is approximately inverse to the processing for transmitting an e- mail is performed on the received data, and the resulting data is provided to the display unit ex358.
  • the video signal processing unit ex355 compresses and codes video signals supplied from the camera unit ex365 using the video coding method shown in each of embodiments, and transmits the coded video data to the multiplexing/demultiplexing unit ex353.
  • the audio signal processing unit ex354 codes audio signals collected by the audio input unit ex356, and transmits the coded audio data to the multiplexing/demultiplexing unit ex353.
  • the multiplexing/demultiplexing unit ex353 multiplexes the coded video data supplied from the video signal processing unit ex355 and the coded audio data supplied from the audio signal processing unit ex354, using a predetermined method.
  • the modulation/demodulation unit ex352 performs spread spectrum processing on the multiplexed data, and the transmitting and receiving unit ex351 performs digital-to- analog conversion and frequency conversion on the data so as to transmit the resulting data via the antenna ex350.
  • the multiplexing/demultiplexing unit ex353 demultiplexes the multiplexed data into a video data bit stream and an audio data bit stream, and supplies the video signal processing unit ex355 with the coded video data and the audio signal processing unit ex354 with the coded audio data, through the synchronous bus ex370.
  • the video signal processing unit ex355 decodes the video signal using a video decoding method corresponding to the coding method shown in each of embodiments, and then the display unit ex358 displays, for instance, the video and still images included in the video file linked to the Web page via the LCD control unit ex359. Furthermore, the audio signal processing unit ex354 decodes the audio signal, and the audio output unit ex357 provides the audio.
  • a terminal such as the cellular phone ex1 14 probably have 3 types of implementation configurations including not only (i) a transmitting and receiving terminal including both a coding apparatus and a decoding apparatus, but also (ii) a transmitting terminal including only a coding apparatus and (iii) a receiving terminal including only a decoding apparatus.
  • the digital broadcasting system ex200 receives and transmits the multiplexed data obtained by multiplexing audio data onto video data in the description, the multiplexed data may be data obtained by multiplexing not audio data but character data related to video onto video data, and may be not multiplexed data but video data itself.
  • the video coding method and the video decoding method in each of embodiments can be used in any of the devices and systems described.
  • the advantages described in each of embodiments can be obtained.
  • the present invention is not limited to embodiments, and various modifications and revisions are possible without departing from the scope of the present invention.
  • Video data can be generated by switching, as necessary, between (i) the video coding method or the video coding apparatus shown in each of embodiments and (ii) a video coding method or a video coding apparatus in conformity with a different standard, such as MPEG-2, H.264/AVC, and VC-1.
  • a different standard such as MPEG-2, H.264/AVC, and VC-1.
  • multiplexed data obtained by multiplexing audio data and others onto video data has a structure including identification information indicating to which standard the video data conforms.
  • the specific structure of the multiplexed data including the video data generated in the video coding method and by the video coding apparatus shown in each of embodiments will be hereinafter described.
  • the multiplexed data is a digital stream in the MPEG2-Transport Stream format.
  • Figure 27 illustrates a structure of the multiplexed data.
  • the multiplexed data can be obtained by multiplexing at least one of a video stream, an audio stream, a presentation graphics stream (PG), and an interactive graphics stream.
  • the video stream represents primary video and secondary video of a movie
  • the audio stream (IG) represents a primary audio part and a secondary audio part to be mixed with the primary audio part
  • the presentation graphics stream represents subtitles of the movie.
  • the primary video is normal video to be displayed on a screen
  • the secondary video is video to be displayed on a smaller window in the primary video.
  • the interactive graphics stream represents an interactive screen to be generated by arranging the GUI components on a screen.
  • the video stream is coded in the video coding method or by the video coding apparatus shown in each of embodiments, or in a video coding method or by a video coding apparatus in conformity with a conventional standard, such as MPEG- 2, H.264/AVC, and VC-1.
  • the audio stream is coded in accordance with a standard, such as Dolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM.
  • Each stream included in the multiplexed data is identified by PID. For example, 0x101 1 is allocated to the video stream to be used for video of a movie, 0x1 100 to 0x1 1 1 F are allocated to the audio streams, 0x1200 to 0x121 F are allocated to the presentation graphics streams, 0x1400 to 0x141 F are allocated to the interactive graphics streams, 0x1 B00 to 0x1 B1 F are allocated to the video streams to be used for secondary video of the movie, and 0x1 A00 to 0x1 A1 F are allocated to the audio streams to be used for the secondary video to be mixed with the primary audio.
  • Figure 28 schematically illustrates how data is multiplexed.
  • a video stream ex235 composed of video frames and an audio stream ex238 composed of audio frames are transformed into a stream of PES packets ex236 and a stream of PES packets ex239, and further into TS packets ex237 and TS packets ex240, respectively.
  • data of a presentation graphics stream ex241 and data of an interactive graphics stream ex244 are transformed into a stream of PES packets ex242 and a stream of PES packets ex245, and further into TS packets ex243 and TS packets ex246, respectively.
  • These TS packets are multiplexed into a stream to obtain multiplexed data ex247.
  • Figure 29 illustrates how a video stream is stored in a stream of PES packets in more detail.
  • the first bar in Figure 29 shows a video frame stream in a video stream.
  • the second bar shows the stream of PES packets.
  • the video stream is divided into pictures as I pictures, B pictures, and P pictures each of which is a video presentation unit, and the pictures are stored in a payload of each of the PES packets.
  • Each of the PES packets has a PES header, and the PES header stores a Presentation Time-Stamp (PTS) indicating a display time of the picture, and a Decoding Time-Stamp (DTS) indicating a decoding time of the picture.
  • PTS Presentation Time-Stamp
  • DTS Decoding Time-Stamp
  • FIG 30 illustrates a format of TS packets to be finally written on the multiplexed data.
  • Each of the TS packets is a 188-byte fixed length packet including a 4-byte TS header having information, such as a PID for identifying a stream and a 184-byte TS payload for storing data.
  • the PES packets are divided, and stored in the TS payloads, respectively.
  • each of the TS packets is given a 4-byte TP_Extra_Header, thus resulting in 192-byte source packets.
  • the source packets are written on the multiplexed data.
  • the TP_Extra_Header stores information such as an Arrival_Time_Stamp (ATS).
  • ATS Arrival_Time_Stamp
  • the ATS shows a transfer start time at which each of the TS packets is to be transferred to a PID filter.
  • the source packets are arranged in the multiplexed data as shown at the bottom of Figure 30.
  • the numbers incrementing from the head of the multiplexed data are called source packet numbers (SPNs).
  • Each of the TS packets included in the multiplexed data includes not only streams of audio, video, subtitles and others, but also a Program Association Table (PAT), a Program Map Table (PMT), and a Program Clock Reference (PCR).
  • the PAT shows what a PID in a PMT used in the multiplexed data indicates, and a PID of the PAT itself is registered as zero.
  • the PMT stores PIDs of the streams of video, audio, subtitles and others included in the multiplexed data, and attribute information of the streams corresponding to the PIDs.
  • the PMT also has various descriptors relating to the multiplexed data. The descriptors have information such as copy control information showing whether copying of the multiplexed data is permitted or not.
  • the PCR stores STC time information corresponding to an ATS showing when the PCR packet is transferred to a decoder, in order to achieve synchronization between an Arrival Time Clock (ATC) that is a time axis of ATSs, and an System Time Clock (STC) that is a time axis of PTSs and DTSs.
  • ATC Arrival Time Clock
  • STC System Time Clock
  • FIG 31 illustrates the data structure of the PMT in detail.
  • a PMT header is disposed at the top of the PMT.
  • the PMT header describes the length of data included in the PMT and others.
  • a plurality of descriptors relating to the multiplexed data is disposed after the PMT header. Information such as the copy control information is described in the descriptors.
  • a plurality of pieces of stream information relating to the streams included in the multiplexed data is disposed.
  • Each piece of stream information includes stream descriptors each describing information, such as a stream type for identifying a compression codec of a stream, a stream PID, and stream attribute information (such as a frame rate or an aspect ratio).
  • the stream descriptors are equal in number to the number of streams in the multiplexed data.
  • each of the multiplexed data information files is management information of the multiplexed data as shown in Figure 32.
  • the multiplexed data information files are in one to one correspondence with the multiplexed data, and each of the files includes multiplexed data information, stream attribute information, and an entry map.
  • the multiplexed data includes a system rate, a reproduction start time, and a reproduction end time.
  • the system rate indicates the maximum transfer rate at which a system target decoder to be described later transfers the multiplexed data to a PID filter.
  • the intervals of the ATSs included in the multiplexed data are set to not higher than a system rate.
  • the reproduction start time indicates a PTS in a video frame at the head of the multiplexed data. An interval of one frame is added to a PTS in a video frame at the end of the multiplexed data, and the PTS is set to the reproduction end time.
  • a piece of attribute information is registered in the stream attribute information, for each PID of each stream included in the multiplexed data.
  • Each piece of attribute information has different information depending on whether the corresponding stream is a video stream, an audio stream, a presentation graphics stream, or an interactive graphics stream.
  • Each piece of video stream attribute information carries information including what kind of compression codec is used for compressing the video stream, and the resolution, aspect ratio and frame rate of the pieces of picture data that is included in the video stream.
  • Each piece of audio stream attribute information carries information including what kind of compression codec is used for compressing the audio stream, how many channels are included in the audio stream, which language the audio stream supports, and how high the sampling frequency is.
  • the video stream attribute information and the audio stream attribute information are used for initialization of a decoder before the player plays back the information.
  • the multiplexed data to be used is of a stream type included in the PMT. Furthermore, when the multiplexed data is recorded on a recording medium, the video stream attribute information included in the multiplexed data information is used. More specifically, the video coding method or the video coding apparatus described in each of embodiments includes a step or a unit for allocating unique information indicating video data generated by the video coding method or the video coding apparatus in each of embodiments, to the stream type included in the PMT or the video stream attribute information. With the configuration, the video data generated by the video coding method or the video coding apparatus described in each of embodiments can be distinguished from video data that conforms to another standard.
  • Step 34 illustrates steps of the video decoding method.
  • Step exS100 the stream type included in the PMT or the video stream attribute information is obtained from the multiplexed data.
  • Step exS101 it is determined whether or not the stream type or the video stream attribute information indicates that the multiplexed data is generated by the video coding method or the video coding apparatus in each of embodiments.
  • Step exS102 decoding is performed by the video decoding method in each of embodiments.
  • Step exS103 decoding is performed by a video decoding method in conformity with the conventional standards.
  • the video coding method or apparatus can be used in the devices and systems described above.
  • Each of the video coding method, the video coding apparatus, the video decoding method, and the video decoding apparatus in each of embodiments is typically achieved in the form of an integrated circuit or a Large Scale Integrated (LSI) circuit.
  • LSI Large Scale Integrated
  • Figure 35 illustrates a configuration of the LSI ex500 that is made into one chip.
  • the LSI ex500 includes elements ex501 , ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 to be described below, and the elements are connected to each other through a bus ex510.
  • the power supply circuit unit ex505 is activated by supplying each of the elements with power when the power supply circuit unit ex505 is turned on.
  • the LSI ex500 receives an AV signal from a microphone ex1 17, a camera ex1 13, and others through an AV IO ex509 under control of a control unit ex501 including a CPU ex502, a memory controller ex503, a stream controller ex504, and a driving frequency control unit ex512.
  • the received AV signal is temporarily stored in an external memory ex51 1 , such as an SDRAM.
  • the stored data is segmented into data portions according to the processing amount and speed to be transmitted to a signal processing unit ex507.
  • the signal processing unit ex507 codes an audio signal and/or a video signal.
  • the coding of the video signal is the coding described in each of embodiments.
  • the signal processing unit ex507 sometimes multiplexes the coded audio data and the coded video data, and a stream IO ex506 provides the multiplexed data outside.
  • the provided multiplexed data is transmitted to the base station ex107, or written on the recording media ex215.
  • the data should be temporarily stored in the buffer ex508 so that the data sets are synchronized with each other.
  • the memory ex51 1 is an element outside the LSI ex500, it may be included in the LSI ex500.
  • the buffer ex508 is not limited to one buffer, but may be composed of buffers. Furthermore, the LSI ex500 may be made into one chip or a plurality of chips.
  • control unit ex510 includes the CPU ex502, the memory controller ex503, the stream controller ex504, the driving frequency control unit ex512
  • the configuration of the control unit ex510 is not limited to such.
  • the signal processing unit ex507 may further include a CPU. Inclusion of another CPU in the signal processing unit ex507 can improve the processing speed.
  • the CPU ex502 may serve as or be a part of the signal processing unit ex507, and, for example, may include an audio signal processing unit.
  • the control unit ex501 includes the signal processing unit ex507 or the CPU ex502 including a part of the signal processing unit ex507.
  • LSI The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.
  • ways to achieve integration are not limited to the LSI, and a special circuit or a general purpose processor and so forth can also achieve the integration.
  • Field Programmable Gate Array (FPGA) that can be programmed after manufacturing LSIs or a reconfigurable processor that allows re-configuration of the connection or configuration of an LSI can be used for the same purpose.
  • FPGA Field Programmable Gate Array
  • a reconfigurable processor that allows re-configuration of the connection or configuration of an LSI can be used for the same purpose.
  • a brand-new technology may replace LSI.
  • the functional blocks can be integrated using such a technology. The possibility is that the present invention is applied to biotechnology.
  • the processing amount probably increases.
  • the LSI ex500 needs to be set to a driving frequency higher than that of the CPU ex502 to be used when video data in conformity with the conventional standard is decoded.
  • the driving frequency is set higher, there is a problem that the power consumption increases.
  • the video decoding apparatus such as the television ex300 and the LSI ex500 is configured to determine to which standard the video data conforms, and switch between the driving frequencies according to the determined standard.
  • Figure 36 illustrates a configuration ex800.
  • a driving frequency switching unit ex803 sets a driving frequency to a higher driving frequency when video data is generated by the video coding method or the video coding apparatus described in each of embodiments. Then, the driving frequency switching unit ex803 instructs a decoding processing unit ex801 that executes the video decoding method described in each of embodiments to decode the video data.
  • the driving frequency switching unit ex803 sets a driving frequency to a lower driving frequency than that of the video data generated by the video coding method or the video coding apparatus described in each of embodiments. Then, the driving frequency switching unit ex803 instructs the decoding processing unit ex802 that conforms to the conventional standard to decode the video data.
  • the driving frequency switching unit ex803 includes the CPU ex502 and the driving frequency control unit ex512 in Figure 35.
  • each of the decoding processing unit ex801 that executes the video decoding method described in each of embodiments and the decoding processing unit ex802 that conforms to the conventional standard corresponds to the signal processing unit ex507 in Figure 33.
  • the CPU ex502 determines to which standard the video data conforms.
  • the driving frequency control unit ex512 determines a driving frequency based on a signal from the CPU ex502.
  • the signal processing unit ex507 decodes the video data based on the signal from the CPU ex502. For example, the identification information described is probably used for identifying the video data.
  • the identification information is not limited to the one described above but may be any information as long as the information indicates to which standard the video data conforms. For example, when which standard video data conforms to can be determined based on an external signal for determining that the video data is used for a television or a disk, etc., the determination may be made based on such an external signal.
  • the CPU ex502 selects a driving frequency based on, for example, a look-up table in which the standards of the video data are associated with the driving frequencies as shown in Figure 38.
  • the driving frequency can be selected by storing the look-up table in the buffer ex508 and in an internal memory of an LSI, and with reference to the look-up table by the CPU ex502.
  • Figure 37 illustrates steps for executing a method.
  • Step exS200 the signal processing unit ex507 obtains identification information from the multiplexed data.
  • Step exS201 the CPU ex502 determines whether or not the video data is generated by the coding method and the coding apparatus described in each of embodiments, based on the identification information.
  • Step exS202 the CPU ex502 transmits a signal for setting the driving frequency to a higher driving frequency to the driving frequency control unit ex512. Then, the driving frequency control unit ex512 sets the driving frequency to the higher driving frequency.
  • Step exS203 when the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2, H.264/AVC, and VC-1 , in Step exS203, the CPU ex502 transmits a signal for setting the driving frequency to a lower driving frequency to the driving frequency control unit ex512. Then, the driving frequency control unit ex512 sets the driving frequency to the lower driving frequency than that in the case where the video data is generated by the video coding method and the video coding apparatus described in each of embodiment.
  • the conventional standard such as MPEG-2, H.264/AVC, and VC-1
  • the power conservation effect can be improved by changing the voltage to be applied to the LSI ex500 or an apparatus including the LSI ex500.
  • the voltage to be applied to the LSI ex500 or the apparatus including the LSI ex500 is probably set to a voltage lower than that in the case where the driving frequency is set higher.
  • the driving frequency when the processing amount for decoding is larger, the driving frequency may be set higher, and when the processing amount for decoding is smaller, the driving frequency may be set lower as the method for setting the driving frequency.
  • the setting method is not limited to the ones described above.
  • the driving frequency is probably set in reverse order to the setting described above.
  • the method for setting the driving frequency is not limited to the method for setting the driving frequency lower.
  • the identification information indicates that the video data is generated by the video coding method and the video coding apparatus described in each of embodiments
  • the voltage to be applied to the LSI ex500 or the apparatus including the LSI ex500 is probably set higher.
  • the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2, H.264/AVC, and VC-1
  • the voltage to be applied to the LSI ex500 or the apparatus including the LSI ex500 is probably set lower.
  • the driving of the CPU ex502 does not probably have to be suspended.
  • the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2, H.264/AVC, and VC-1
  • the driving of the CPU ex502 is probably suspended at a given time because the CPU ex502 has extra processing capacity.
  • the suspending time is probably set shorter than that in the case where when the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2, H.264/AVC, and VC-1.
  • the power conservation effect can be improved by switching between the driving frequencies in accordance with the standard to which the video data conforms. Furthermore, when the LSI ex500 or the apparatus including the LSI ex500 is driven using a battery, the battery life can be extended with the power conservation effect.
  • the decoding processing unit for implementing the video decoding method described in each of embodiments and the decoding processing unit that conforms to the conventional standard, such as MPEG-2, H.264/AVC, and VC-1 are partly shared.
  • Ex900 in Figure 39A shows an example of the configuration.
  • the video decoding method described in each of embodiments and the video decoding method that conforms to H.264/AVC have, partly in common, the details of processing, such as entropy coding, inverse quantization, deblocking filtering, and motion compensated prediction.
  • the details of processing to be shared may include use of a decoding processing unit ex902 that conforms to H.264/AVC.
  • a dedicated decoding processing unit ex901 is probably used for other processing unique to the present invention. Since the present invention is characterized by application of filtering such as deblocking and adaptive loop filtering, for example, the dedicated decoding processing unit ex901 is used for such filtering. Otherwise, the decoding processing unit is probably shared for one of the entropy decoding, inverse quantization, spatial or motion compensated prediction, or all of the processing.
  • the decoding processing unit for implementing the video decoding method described in each of embodiments may be shared for the processing to be shared, and a dedicated decoding processing unit may be used for processing unique to that of H.264/AVC.
  • ex1000 in Figure 39B shows another example in that processing is partly shared.
  • This example uses a configuration including a dedicated decoding processing unit ex1001 that supports the processing unique to the present invention, a dedicated decoding processing unit ex1002 that supports the processing unique to another conventional standard, and a decoding processing unit ex1003 that supports processing to be shared between the video decoding method in the present invention and the conventional video decoding method.
  • the dedicated decoding processing units ex1001 and ex1002 are not necessarily specialized for the processing of the present invention and the processing of the conventional standard, respectively, and may be the ones capable of implementing general processing.
  • the configuration can be implemented by the LSI ex500.
  • the present invention relates to correcting of quantized prediction error signal prior to its further processing, suitable for employment within hybrid encoders and decoders.
  • the quantized prediction signal is corrected based on the clipped reconstructed signal.
  • the further processing may be an adaptive filtering such as Wiener filtering with three inputs, i.e. considering the prediction error signal, the prediction signal and the reconstructed signal.
  • the correction may be performed by adding the difference between the clipped reconstructed signal and the reconstructed signal to the quantized prediction error signal, or by subtracting the prediction signal from the clipped reconstructed signal.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)

Abstract

La présente invention porte sur la correction d'un signal d'erreur de prédiction quantifié avant son traitement ultérieur, appropriée pour être employée dans des codeurs et décodeurs hybrides. En particulier, le signal de prédiction quantifié est corrigé sur la base du signal reconstruit écrêté. Le traitement ultérieur peut être un filtrage adaptatif, tel qu'un filtrage de Wiener à trois entrées, c'est-à-dire considérant le signal d'erreur de prédiction, le signal de prédiction et le signal reconstruit. La correction peut être effectuée par addition de la différence entre le signal reconstruit écrêté et le signal reconstruit au signal d'erreur de prédiction quantifié, ou par soustraction du signal de prédiction au signal reconstruit écrêté.
PCT/EP2011/003721 2010-07-26 2011-07-25 Signal d'erreur de prédiction quantifié pour filtre de wiener à trois entrées WO2012013327A1 (fr)

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