Abstract: A bitstream generator is described, for placing variable length coding (VLC) data into a fixed width data stream. The bitstream generator includes an input for receiving VLC data; the VLC data may be separated into a value component, and a length component. The bitstream generator also includes an output buffer, a memory module, for storing the VLC data before sending. The bitstream generator also incorporates a backup buffer, which is used to store any overflow data which does not fit in the output buffer. A comparator is used, to determine how much of the VLC data will fit in the output buffer. Any portion of the VLC data which does not fit in the output buffer is stored in the backup buffer.

Abstract: A method and system are provided for encoding a plurality of integers with variable-length code tables constructed by combining a plurality of structured code tables. Each code table has an associated set of integer values; the sets are disjoint and exhaustive, so that every integer appears in exactly one set. An integer is encoded using the codebook associated with the set in which the integer appears.

Abstract: An entropy encoder includes an apparatus for producing a data stream which comprises two reference points, of code words of variable lengths, the apparatus comprising a first device for writing at least a part of a code word into the data stream in a first direction of writing, starting from a first reference point, and a second device for writing at least a part of a code word into the data stream in a second direction of writing, which is opposite to the first direction of writing, starting from the other reference point. In particular, when a raster having a plurality of segments is used to write the code words of variable lengths into the data stream, the number of the code words which can be written starting at raster points is doubled, in the best case, such that the data stream of code words of variable lengths is robust toward a propagation of sequence errors.

Abstract: A video coding method comprises dividing a coefficient vector into two or more sub-vectors, each sub-vector having a length less than or equal to a length of the coefficient vector, indicating a size of each sub-vector and a position of each sub-vector within the coefficient vector, and forming a block corresponding to each sub-vector

Abstract: The invention includes: a bitstream updating output unit configured to receive a bitstream and update a syntax element located at a beginning of the bitstream according to a code length thereof and outputs the syntax element; a bitstream decoding unit configured to decode, in response to a decode request, a variable-length code of the syntax element outputted from the bitstream updating output unit; a zerosLeft updating unit configured to update zerosLeft based on a specific syntax element decoded by the bitstream decoding unit; a run_before remaining number updating unit configured to update a run_before remaining number based on a specific syntax element decoded by the bitstream decoding unit; and a syntax selection unit configured to select a syntax element to be decoded by the bitstream decoding unit. Thus, multiple zero run_before syntaxes and one non-zero run_before syntax, or multiple zero run_before syntaxes are decoded all at once.

Abstract: An entropy encoder includes an apparatus for producing a data stream which comprises two reference points, of code words of variable lengths, the apparatus comprising a first device for writing at least a part of a code word into the data stream in a first direction of writing, starting from a first reference point, and a second device for writing at least a part of a code word into the data stream in a second direction of writing, which is opposite to the first direction of writing, starting from the other reference point. In particular, when a raster having a plurality of segments is used to write the code words of variable lengths into the data stream, the number of the code words which can be written starting at raster points is doubled, in the best case, such that the data stream of code words of variable lengths is robust toward a propagation of sequence errors.

Abstract: Aspects of the present invention relate to systems and methods for selectively determining a quantization parameter based on coding parameters. In some embodiments, a quantization parameter selection may be based on the presence of non-zero transform coefficients as well as other parameters. Some embodiments relate to rewriting a multi-layer bitstream to a single-layer bitstream with a quantization parameter selected with reference to transform coefficients. Some embodiments convert a scalable, multi-layer video sequence into a single-layer, non-scalable video sequence that is compatible with legacy devices.

Abstract: A process encodes video or image data. The process includes estimating forms of a plurality of functions and estimating a best quality value for producing encoded frames with sizes that satisfy one or more constraints. Each function relates encoded size to encoded quality for an associated frame. Each frame has data for one or more images. The constraints are associated with transmission line bandwidth or receiver buffer size. The estimating a best quality value is based in part on the functions. The process also includes transmitting frames encoded with approximately the best quality value to a transmission line.

Abstract: An image decoding device according to the present invention is an image decoding device responding to decoding of an image encoding method selecting an encoding table and an encoding format to use according to the kind of a parameter included in encoded data and comprises a bit stream processing unit converting a bit stream of the encoded data into an intermediate format and an image processing unit decoding data converted into the intermediate format and converting the same into image data. The bit stream processing unit and the image processing unit start independently. An image encoding device according to the present invention, in the same manner, comprises an image processing unit converting image data to be encoded into an intermediate format and a bit stream processing unit encoding the data converted into the intermediate format and converting the same into a bit stream. Thereby, image encoding and decoding processings with a low operation frequency and low power consumption is realized.

Abstract: A digital media encoder/decoder includes signaling of various modes relating to computation complexity and precision at decoding. The encoder may send a syntax element indicating arithmetic precision (e.g., using 16 or 32-bit operations) of the transform operations performed at decoding. The encoder also may signal whether to apply scaling at the decoder output, which permits a wider dynamic range of intermediate data at decoding, but adds to computational complexity due to the scaling operation.

Abstract: An image coding apparatus (100) which reduces buffer capacity to a minimum and includes an image coding processing unit (110) which generates intermediate data by executing a part of a process in the coding on the image data; a packetizing unit (120) which generates an image stream by executing a process other than the part of the process in the coding on the intermediate data, such as for example arithmetic coding, and packetizes the generated image stream in synchronization with the image stream generation process.

Abstract: Video coding efficiency is improved by jointly coding the x and y components of motion vectors with a single variable length code. The motion vector components for a block of pixels are predicted based on motion vectors of neighboring blocks of pixels. The predicted x and y components are then jointly coded by assigning a single variable length code corresponding to the pair of components, rather than a separate code for each component. If the x and y components do not have a corresponding entry in the coding table, they are coded with an escape code followed by fixed length codes.

Abstract: The invention is related to methods and apparatus that can advantageously be used in a video encoder to improve picture quality, to improve the speed of encoding, and the like. One embodiment of the invention advantageously computes activity measures using an efficient L1-norm, which can advantageously be relatively quickly computed by selected microprocessors. Another embodiment of the invention advantageously allocates bits to macroblocks of a picture based at least in part on the motion activities of the macroblocks.

Abstract: A method, and apparatus, and logic encoded in one or more computer-readable tangible medium to carry out a method. The method is to code an ordered sequence of quantized transform coefficients of a block of image data using a hybrid coding method that includes determining a breakpoint location in the sequence between a low frequency region and a high frequency region; coding the low-frequency region using a selected low-frequency variable length coding method; coding the high-frequency region using a selected high-frequency variable length coding method; and coding the location of the breakpoint. The breakpoint location is determined as a function of the sequence such that different sequences can have different breakpoints.

Abstract: The digital video referencing frame image is compressed block by block by applying lossless compression algorithm to pixel components with full length, or 1 bit, 2 bits, 3 bits or 4 bits LSB bits truncation. If a sub-block has high complexity which results in more than 3 bits error for most pixel components, a transfer algorithm with quantization and VLC coding is applied to compress this sub-block. Should the complexity is higher than a threshold or at least one sub-block having error of more than 3 bits for most pixel components, truncating 1 LSB bit of sub-block with simple pattern to save more bits to be allocate to code the sub-block with highest complex pattern.

Abstract: In a method for transmission of video information between HTTP servers and clients in a shared network resource, particularly Internet, the video information is stored as a video file consisting of packet-divided video streams compression-coded with average bit rates t(c) which cover the clients' expected channel bit rates s. Each packet and the video file are supplied with a header containing information for realizing a bandwidth-scalable video transmission over a suitable version of HTTP. During transmission switching between the video streams takes place on the basis pf an estimation of the channel bit rate s and the information in the packet header, such that the bit rate t(c) is adapted to the client's actual channel bit rate s. In a method for client-executed search and retrieval of video information in a shared network resource, particularly searching of a video frame Fx in a packet-divided video stream, the packets in a video stream are divipacket packet in each group.

Abstract: Variable length coding (VLC) techniques are described for coded block patterns (CBPs) used in block-based video coding. In VLC of CBPs, patterns of transform coefficients that are more likely to occur are coded with shorter codes, while patterns of coefficients that are less likely to occur are coded with longer codes. According to the techniques of this disclosure, several different VLC tables are stored in the coding devices. During the encoding and decoding processes, one of the VLC tables is selected and used to perform the coding of CBPs for a given video block. The table may be selected based on a number of neighboring video blocks to the current video block that include non-zero transform coefficients. The techniques may be particularly useful in the coding of video blocks of enhancement layers in scalable video coding (SVC).

Abstract: A system and a method for deblocking a reconstructed/decoded picture in a scalable video encoding/decoding system is provided. Deblocking is accomplished by applying a filter to smooth pixel values adjacent to a boundary shared by two blocks. The type of the filter applied depends on quantization parameter (QP) values assigned to the two blocks. An enhancement layer (EL) block is assigned a QP value based on its coded information and the QP value of its corresponding base layer (BL) block(s).

Abstract: The present invention is to provide a variable length decoding method for decoding complete binary tree code, which is implemented to an entropy coding module for executing the process comprising the steps of: procuring a TabIndex to calculate a value T=?log2(TabIndex)?; reading T bits from a bitstream to obtain a first result M; determining whether or not the result M is smaller than (TabIndex?(1<<T)); if not, obtaining Index equal to (1<<T)?M?1; otherwise, reading 1 bits from the bitstream to obtain a second result N; and then obtaining Index equal to TabIndex?2×M?N?1, so as to decode data stream of video more efficiently and fast.

Abstract: A coding and/or decoding system includes: a code-word table for storing therein a plurality of code words, which are capable of being decoded both in forward and backward directions and which are formed so that delimiters of the code words are capable of being identified by a predetermined weight of the code words, so that the code words correspond to different source symbols; an encoder for selecting code words corresponding to inputted source symbols from the code-word table; and a synchronization interval setting part for preparing coded data every predetermined interval using the code words selected by the encoder and for inserting stuffing codes capable of being decoded in the backward direction. Thus, it is possible to decrease useless bit patterns to enhance the coding efficiency by smaller amounts of calculation and storage, and to decode variable length codes both in the forward and backward directions even if the synchronization interval is set every interval using the stuffing bits.

Abstract: A coding and/or decoding system includes: a code-word table for storing therein a plurality of code words, which are capable of being decoded both in forward and backward directions and which are formed so that delimiters of the code words are capable of being identified by a predetermined weight of the code words, so that the code words correspond to different source symbols; an encoder for selecting code words corresponding to inputted source symbols from the code-word table; and a synchronization interval setting part for preparing coded data every predetermined interval using the code words selected by the encoder and for inserting stuffing codes capable of being decoded in the backward direction. Thus, it is possible to decrease useless bit patterns to enhance the coding efficiency by smaller amounts of calculation and storage, and to decode variable length codes both in the forward and backward directions even if the synchronization interval is set every interval using the stuffing bits.

Abstract: A circuit generally including a first module, a second module and a third module is disclosed. The first module may be configured to (i) generate a plurality of parsed residual blocks by parsing a plurality of 4×4 CAVLC (context-based adaptive variable length coding) residual blocks received in an input signal and (ii) generate a plurality of metric signals resulting from the parsing of the 4×4 CAVLC residual blocks. The second module configured to generate a plurality of scanning position signals based on the metric signals. The third module configured to generating an 8×8 CABAC (context-based adaptive binary arithmetic coding) residual block in an output signal by up-sampling the parsed residual blocks based on the scanning position signals.

Abstract: Techniques for efficient significant coefficients coding in scalable video codecs are described. In one configuration, a device including a processing circuit having a set of instruction operative to generate initialization tables for a current frame or slice is provided. The initialization tables have statistics of a significant coefficient pass for a previous encoded frame or slice using scalable video coding. The device also includes a transmitter to transmit the initialization tables with the current frame or slice to a decoder. The decoder can decode a frame or slice with the transmitted initialization tables. The decoder may also use resident default initialization tables.

Abstract: This disclosure describes techniques for coding an enhancement layer in a scalable video coding (SVC) scheme. The techniques may be used in coding transform coefficients, and are particularly useful in variable length coding of refinement coefficients of an enhancement layer of a SVC scheme. According to the techniques of this disclosure, information is transmitted from an encoder device to a decoder device that identifies which variable length coding tables should be used for the decoding two or more different types of video blocks. The information may be transmitted once per frame (or other coded unit), and may identify a first table to be used for intra-coded blocks and a second table to be used for inter-coded blocks of a respective frame. The decoder performs table selection based on this information, and decodes different types of video blocks using the selected table for each block type.

Abstract: This disclosure describes techniques for coding an enhancement layer in a scalable video coding (SVC) scheme. The techniques may be used in variable length coding of refinement coefficients of an enhancement layer of a SVC scheme. According to this disclosure, a method may comprise determining first statistics associated with a first type of video block. determining second statistics associated with a second type of video block, selecting a first variable length coding (VLC) table from a plurality of VLC tables to be used in coding the first type of video block based on the first statistics, selecting a second VLC table from the plurality of VLC tables to be used in coding the second type of video block based on the second statistics, coding video blocks of the first type based on the first VLC table, and coding video blocks of the second type based on the second VLC table.

Abstract: This disclosure describes techniques for coding an enhancement layer in a scalable video coding (SVC) scheme. The techniques involve run-length coding of significant coefficients and refinement coefficients of the enhancement layer. Rather than performing two different run-length passes to separately code the significant coefficients and refinement coefficients, the techniques of this disclosure perform run-length coding of the significant coefficients and refinement coefficients together. Therefore, run values of the run-length coding codes the significant coefficients with the refinement coefficients. Additional techniques are also described, which can eliminate the need to send sign information for some of the refinement coefficients. Instead, this sign information for some of the refinement coefficients may be derived at the decoder based on the sign values of corresponding coefficients of previously encoded layers of the SVC scheme, which can further improve compression efficiency.

Abstract: A communication system including a transmitter, a receiver, and a serial link, in which encoded data (e.g., encoded video data and encoded auxiliary data) are transmitted from the transmitter to the receiver. The serial link can but need not be a TMDS or TMDS-like link. In typical embodiments, alternating bursts of encoded video data and encoded auxiliary data are transmitted over each of one or more channels of the link. Other aspects of the invention are transmitters for use in encoding data for transmission over a serial link, and methods for sending encoded data over a serial link. In accordance with the invention, the data to be transmitted are encoded using a subset (sometimes referred to as a selected set of code words) of a full set of code words.

Abstract: An MPEG-4 encoder utilizing an H.263 multimedia chip. The MPEG-4 encoder includes a DC (Direct Current) predictor for predicting a DC component of the image frame encoded by an H.263 standard upon receiving a prescribed MPEG-4 quantization value, and an MPEG-4 reconstruction image memory for converting the H.263 reconstruction image into an MPEG-4 reconstruction image, and storing the MPEG-4 reconstruction image. The MPEG-4 encoder removes spatial redundancy from source image data entered in frame units using a prescribed H.263 quantization value, predicts a DC component of an image frame having no spatial redundancy using a prescribed MPEG-4 quantization value, performs a VLC (Variable Length Coding) process on the image frame using the predicted DC component, and outputs the VLC-processed image frame in the form of an MPEG-4 bit stream.

Abstract: This invention produces data packets that can vary in length and/or data compression ratio. First, an algorithm is employed to transform a data signal into fixed or variable length data packets at variable data compression ratios. If the algorithm produces fixed length data packets, the fixed length data packets are then converted to variable length data packets, which include only the valid data bytes of the fixed length data packets. Finally, the variable compression ratio, variable length data packets are provided with length codes at each end of each data packet to facilitate bi-directional searching and decompression. The transition from fixed to variable length data packets employs a buffer which stores the fixed length data packets until the fixed length data packets are converted to variable length data packets.

Abstract: A data encoding apparatus operable to encode a plurality of data blocks produces encoded data in accordance with at least one of a selectable target data quantity or a selectable target data quality.

Abstract: A moving picture decoding apparatus includes one or more variable-length decoding units, a data buffer configured to store data output from the one or more variable-length decoding units, and a plurality of image decoding units configured to read the data from the data buffer and to perform image decoding the data.

Abstract: In a moving picture decoding apparatus compliant with a coding standard, such as CABAC of H.264 and the like, for coding of a stream including arithmetic coded data, a first type variable length decoding section performs first variable length decoding including arithmetic decoding to input stream data to generate first stream data beforehand. The first recording control section records a key frame which is selected from the first stream data not needing arithmetic decoding and is necessary in special playback in a first recording region. In decoding, the recorded key frame not needing arithmetic decoding is used, a decoding time is reduced. Accordingly, even when a moving picture stream for special playback such as multiple-fold speed playback is performed, reverse playback and the like, as smooth special playback as known special playback of a moving picture signal which does not include arithmetic coded data can be achieved.

Abstract: A method and system for entropy coding, where parameters indicative of a coded signal are mapped into codeword indexes so that a decoder can reconstruct the coded signal from the codeword indexes. When the parameter space is limited such that the coding is inefficient in that the codewords are not arranged in an orderly or contiguous fashion corresponding to the parameters, a sorting step is used to sort the parameters into different groups so that parameters in different groups are mapped into the codeword indexes in different manners such that the codeword indexes corresponding to the parameters are assigned in a contiguous and orderly manner. The sorting can be based on the absolute values of the parameters in relation with a selected value. In the decoding process, the codewords indexes are also sorted into different groups based on the value of codewords indexex in relation to the selected value.

Abstract: A method and system for dynamic frequency adjustment during video decoding. A decode time for performing a hardware variable length decode (VLD) on a portion of a video clip at a processor is measured. A frequency controlling the processor during video decoding is adjusted based at least in part on the decode time.

Abstract: An image coding apparatus is provided with a unit operable to scan a two-dimensional array of quantized coefficients into scanned quantized coefficients, the scanning being performed from a low frequency component toward a high frequency component; a unit operable to convert the scanned quantized coefficients into a run value and a level value, the run value indicating the number of continuous quantized coefficients, each having a zero value, and the level value indicating a value of a quantized coefficient having a non-zero value; a unit operable to code the run value; and a unit operable to code the level value, wherein the coding of the run value is performed, from a high frequency component toward a low frequency component, in accordance with information that represents a total number of uncoded quantized coefficients which have not been coded.

Abstract: A motion of an image in a block is detected with respect to image data D1, a coding mode to be applied thereto is selected among a plurality of prepared coding modes, and motion compensation is performed for the image data (Step S101). Then, an orthogonal transform coefficient D6 and coding mode information D3 undergo variable-length coding to generate coded data D7 (Step S103). Subsequently, in the variable-length coding of the coding mode information, a probability table for use in arithmetic coding is switched for each of binarization codes included in a binarization pattern of the coding mode information with reference to a coding mode selected in a block adjacent to the block. Thus, the image coding method, image decoding method, image coding apparatus, image decoding apparatus, program, computer data signal, and image transmission system, which are capable of enhancing efficiency of data compression for coding mode information multiplexed on coded data, are realized.

Abstract: An image decoding apparatus is provided with a unit operable to receive coded data including a coded run value and a coded level value, wherein the coded run value is obtained by coding a run value which indicates the number of continuous quantized coefficients, each having a zero value, and the coded level value is obtained by coding a level value which indicates a value of a quantized coefficient having a non-zero value; a unit operable to decode the coded run value to obtain a decoded level value; a unit operable to decode the coded level value to obtain a decoded level value; and a unit operable to obtain quantized coefficients of the block image from the decoded level value and the decoded run value, wherein the decoding of the coded run value is performed from a high frequency component toward a low frequency component, in accordance with information that represents a total number of undecoded quantized coefficients which have not been decoded.

Abstract: An image coding apparatus provides a run-length encoding unit RLE1 that subjects quantized coefficients which are obtained by quantizing frequency components of an image signal to a variable length coding process by using a run value Run that indicates the number of successive zero coefficients and a level value Lev that indicates a value of a non-zero coefficient following the zero coefficients.

Abstract: A variable length coding method is provided for coding coefficients in each block which are obtained by performing frequency transformation on picture data of a moving picture per block having a predetermined size, and includes: a coefficient scanning step of scanning the coefficients in the block in a predetermined order; and a coding step of coding the coefficients scanned in the coefficient scanning step into variable length codes in a predetermined order by switching a plurality of tables to be used for coding. Here, a direction of switching between the tables may be one-directional. Also, the coding may be non-arithmetic coding.

Abstract: A system and method for compressing an image into bit streams allows data to be presented in either lossy or lossless quality. A lossy quality presentation results in some measurable degradation of an image's visual quality upon expansion. A lossless quality presentation displays the image in its original form. The method divides the image to be compressed into a plurality of regions. For each region, a plurality of adjacent pixels are selected and organized into a set. The corresponding sets for each respective region are identified as a group. The pixel sets within each group are encoded and arranged into two bit streams associated with each respective group. Next, each group's respective bit streams are written into a primary bit stream of constant size and possible a supplemental bit stream of variable length for presenting the image in either lossy or lossless quality.

Abstract: A pattern-search based method and apparatus for context-adaptive variable length coding/decoding (CAVLC/CAVLD) is provided. The method analyzes the correlation between bit patterns and blocks. Before CAVLD, a step of bit-stream pattern search is conducted. If a pattern is matched in a look-up table, this invention skips the CAVLD procedure and reconstructs a block directly. Before CAVLC, a step of zig-zag ordered coefficients search is conducted. If a sequence of zig-zag ordered coefficients is matched in a look-up table, a corresponding coded bit-stream can be obtained directly. Compared with the standard CAVLD procedures, this invention improves about 10% performance in memory access speed.

Abstract: For “Super Audio CD” (SACD) the DSD signals are losslessly coded, using framing, prediction and entropy coding. Besides the efficiently encoded signals, a large number of parameters, i.e. the side-information, has to be stored on the SACD too. The smaller the storage capacity that is required for the side-information, the better the overall coding gain is. Therefore coding techniques are applied to the side-information too so as to compress the amount of data of the side information.

Abstract: A method and apparatus for variable accuracy inter-picture timing specification for digital video encoding is disclosed. Specifically, the present invention discloses a system that allows the relative timing of nearby video pictures to be encoded in a very efficient manner. In one embodiment, the display time difference between a current video picture and a nearby video picture is determined. The display time difference is then encoded into a digital representation of the video picture. In a preferred embodiment, the nearby video picture is the most recently transmitted stored picture. For coding efficiency, the display time difference may be encoded using a variable length coding system or arithmetic coding. In an alternate embodiment, the display time difference is encoded as a power of two to reduce the number of bits transmitted.

Abstract: Several code detectors in parallel simultaneously examine varying overlapping segments of a data stream containing variable length codes, referred to as a data window. The data window segments directly address memory structures within each of the code detectors without any previous logic stages. Each code detector is responsible for a range of code lengths, and ignores data window bits that are not relevant to its code length range. Each code detector outputs a possible result to a layer of logic that selects the possible result of the single code detector which contains result data corresponding to a variable length code in the data window.

Abstract: A motion-picture-experts group (MPEG) decoder performs AC prediction to decode first-column or first-row coefficients that are coded as differences from corresponding coefficients in a prior block or an above block. Rather than perform AC prediction between the variable-length decoder (VLD) and the inverse-quantizer (IQ), AC prediction is performed after the IQ. Post-IQ AC prediction allows the VLD and IQ to be constructed as a unified stage, improving decoding speed or efficiency as a single hardware stage can be used for the combined VLD/IQ. Rather than store prior-block quantized DCT coefficients, a coefficient store stores post-IQ DCT coefficients and quantization parameters. A Q-subtractor operates on the IQ output using the current quantization parameter, while another Q-subtractor operates on the stored coefficients and stored quantization parameter. The Q-subtractor subtracts a signed, odd-rounded quantization parameter from a coefficient.

Abstract: Methods and systems for improving performance of data decoding using apriori information about the data steam. In one aspect a decoder may determine the degree of lossiness inherent in the data or in the application of the data as a maximum resolution of data to be decoded and may thereby streamline entropy decoding of the data. For example, in DCT-based image data compression coupled with Huffman or other entropy encoding, apriori data may be analyzed to determine the maximum required resolution in bits of the DCT encoded data so as to simplify the entropy decoding. Other aspects optimize DCT decoding computation with faster approximations where the quantization values indicate a higher degree of lossiness or noise in the DCT encoded data. Apriori information may generally comprise values in the quantization table of a DCT encoded image and may be analyzed to determine the maximum symbol size and/or degree of lossiness.

Abstract: A method of improving performance within video decoders subject to the execution of overlapped motion compensation. The method utilizes a triple-buffering approach to achieve rapid data transfers and to eliminate transfer and decoding delays. Each of the three buffers is sequentially utilized for (i) receipt of decoded macroblock data, (ii) insertion of additional decoded macroblock data from a subsequent decoding stage, and finally (iii) the transfer of the collected macroblock data to a transfer buffer. The method is applicable to a number of multiprocessing decoders, and is especially well suited for MPEG-4 and H.263 multiprocessing decoders.

Abstract: A decoding device includes a variable-length decoding circuit, a first buffer, a second buffer and a DC/AC prediction circuit is disclosed. The variable length decoding circuit decodes a first block and a second block from a compressed media stream. The first and second buffers are electrically coupled with the variable-length decoding circuit to store the first block and the second blocks, respectively. The DC/AC prediction circuit is electrically coupled with the first buffer and the second buffer. The DC/AC prediction circuit may read the first block from the first buffer when the second buffer is storing the second block.

Abstract: Encoded data using reversible variable length code words is input to a forward decoder (123) to be decoded in the forward direction. When an error is detected in the encoded data in the forward decode processing, backward decode processing is started by a backward decoder (126). A decode value determination unit (125) determines a decode value by using the forward and backward decode results and the error detection positions in the encoded data in units of bits and syntax which are respectively detected in the forward decoding and the backward decoding.

Abstract: A picture type identifier, indicating one of intra-picture coding (an I-picture), forward or backward predictive coding (a P-picture) and bi-directionally predictive coding (a B-picture), is included with a picture signal when the signal is encoded and when the signal is decoded. Each of initial and subsequent encoding and decoding is a function of the included picture type.