Abstract: In video compression processing, such as MPEG-2 compression processing, the quantization (Q) matrix used to quantize discrete cosine transform (DCT) coefficients is updated from frame to frame based on a parameterized Q matrix adaptation algorithm. According to the algorithm, the Q matrix for the current frame is generated based on DCT coefficient data from the previously encoded frame of the same type (e.g., I, P, or B) as the current frame. In particular, the Q matrix is generated using a function based on shape parameters (e.g., the slope of the diagonal of the Q matrix and/or the convexity of the diagonal of the Q matrix), where the diagonal slope for the Q matrix of the current frame is generated based on the diagonal slope of a DCT map for the previously encoded frame. Before using the generated Q matrix to quantize the DCT coefficients for the current frame, the Q matrix is preferably adjusted for changes in the target mean from the previously encoded frame to the current frame.

Abstract: The present invention involves a system and method for performing motion estimation. For each candidate motion vector, encoding distortion is determined between a macroblock and a reconstructed macroblock by determining discrete cosine transform cofficients of the macroblock and quantizing the discrete cosine transform coefficients. An estimate unit determines the length of the bit stream required to encode the quantized discrete cosine transform coefficients along with the mode information bits including mode and motion vector information. The reconstructed macroblock is determined based on the quantized discrete cosine transform coefficients. A bit-rate term based on the length of the bit-rate stream is determined and included in the encoding distortion. The candidate motion vector which minimizes the encoding distortion of the macroblock is chosen to be the motion vector for the macroblock.

Abstract: In the case where the code generation volume that the data occupancy rate in the buffer of the image decoding apparatus is smaller than the first, second or the third threshold value corresponding to the first, second or the third image currently being coded from among the first, second and third threshold values of the data occupancy rate set corresponding to the first image to be intra-coded, the second image to be directionally predictive coded and the third image to be bidirectionally predictive coded respectively, the coding processing on the first, second or the third image presently being coded will be stopped.

Abstract: A coder of the present invention is adapted to reproduce a signal of quality at a low coding rate even when a video or audio signal continuously supplied thereto should be coded in real time. The coder includes: a quantizer for quantizing the input signal; an encoder for encoding the output of the quantizer and outputting coded data; and a quantization parameter supply circuit for supplying a quantization parameter to the quantizer. If a scene change detector has detected a scene change, the supply circuit supplies a quantization parameter, which has been determined adaptively to a scene newly appearing after the scene change, to the quantizer. Otherwise, the supply circuit supplies a quantization parameter, which has been determined at such a value as to stabilize a coding rate, to the quantizer. In this manner, an average coding rate can be controlled and coding processing can be performed adaptively to individual scenes.

Abstract: An MPEG coded and compressed video signal is received and decompressed for display. Prior to storing frames required for motion compensation in memory, pixel blocks are recompressed into DPCM prediction error values to reduce bandwidth and frame memory requirements. Fixed length quantization and dequantization tables (FIG. 2) have N levels (e.g., 15 levels), and each level has an associated output symbol of predominantly M bits (e.g., 4 bits), except that at least one of said N levels (e.g., level 7) is defined by a unique short symbol having less than M bits (e.g., 3 bits), and input data for that level is received at a desired rate. Each time a short symbol is used to represent a data value, bandwidth and memory are reduced and/or preserved for other uses, for example, inserting overhead data into a fixed-size data stream. For large sequences of data, such as exists for video data for example, the reduction in memory and bandwidth is significant.

Abstract: A method and device for producing and delivering constant quality digital video bitstreams over channels of any bit-rate and variability are provided. The method and device may be applicable to any standardized video coding system, but preferably within the MPEG-4 standard. For constant capacity networks, the method and the device re-distribute the coded bits in a constant-quality variable bit-rate bitstream to construct a constant bit-rate bitstream. For variable capacity networks, the method and the device achieve constant quality as described by a metric that incorporate both spatial and temporal visual quality. The method and the device incorporate user, network, and channel parameters in controlling the bit-rate while encoding video material.

Abstract: A system and method for generating an MPEG compliant video stream with satisfactory visual quality. The method employs re-encoding at a higher (or lower) bit rate, only the segments with unsatisfactory visual picture quality while retaining other parts of the original video stream and then merging the re-encoded segments with the remaining original portions. If the original video stream is coded at a reasonable bit rate, the number and length of those segments with unsatisfactory visual picture quality will be few and short. Re-encoding only those segments can save very significant amount of cost and only requires minimal additional storage space. Furthermore, the portions with satisfactory picture quality will be retained. The system and method is applicable to MPEG and non-MPEG compliant data streams.

Abstract: A moving image encoding apparatus which has a similar function to noise elimination by a pre-processing filter without requiring a large amount of calculation and a large apparatus scale. A quantization circuit performs quantization with a quantization step size of a characteristic different from that of a quantization step size which is used by a dequantization circuit and an encoding circuit to eliminate coding of noise components mixed in an input image. An encoding control circuit controls the noise elimination characteristic of the quantization circuit with a noise elimination parameter based on an output of a moving/still discrimination circuit and stored contents of a transmission buffer.

Abstract: A method encodes a video a video objects. For each candidate object, a quantizer parameter and a skip parameter that jointly minimizes an average total distortion in the video are determined while satisfying predetermined constraints. The average total distortion includes spatial distortion of coded objects and spatial and temporal distortion of uncoded objects. Then, the candidate objects is encoded as the coded objects with the quantizer parameter and the skip parameter, and the candidate objects is skipped as the uncoded objects with the skip parameter.

Abstract: Method, software, and apparatus (100, 300, 400) for performing rate controlled image compression are provided. A quantization matrix scaling factor that results in compression to a predetermined byte size is determined by first summing the absolute value of the difference of neighboring pixels selected from a plurality of rectangular regions of the image. The sums are then input to a model function that is evaluated to obtain the quantization matrix scaling factor. According to preferred embodiments the model function involves a dot product operation between a vector that includes the sums and a second vector that includes region weights.

Abstract: A picture signal processing system is disclosed, that comprises a decoder for generating the number of encoded bits and/or an average quantizing scale as representative value(s) of encoding parameters of an input encoded picture signal, decoding the input encoded picture signal, generating the decoded picture signal, and outputting the encoding parameters along with the generated decoded picture signal, and an encoder for encoding the decoded picture signal with the encoding parameters.

Abstract: An exemplary video encoder is disclosed that quantizes pel blocks of a video signal based upon one or more of the following: (i) an actual bit distribution of a previously encoded video frame, (ii) a required decoding delay for a splice point, and (iii) an activity measure of a pel block being encoded. Moreover, an exemplary video encoder uses the above quantization techniques to obtain an encoded video stream having seamless in points and seamless out points. Video encoding methods that utilize the above quantization methods are also disclosed.

Abstract: A rate control system suitable for use with a digital video transcoder, such as one conforming to the MPEG standard. The proposed rate control system starts coding with any reasonable set of assumed Group of Pictures (GOP) parameters, thereby avoiding a processing delay of about one GOP which would otherwise be incurred to extract the complete GOP structure information from a pre-compressed bit stream. In addition, the system avoids the need to store the data corresponding to the GOP, thereby reducing the memory required for transcoding. Encoding of a first picture in a sequence or GOP begins without a priori knowledge of the picture type of subsequent pictures. A reasonable set of GOP parameters is assumed to determine an encoding bit budget. The bit budget is gradually corrected as successive pictures are coded according to their picture types. Changes in the GOP structure of pre-compressed bitstreams can be addressed, for example, when switching channels, inserting commercials, and the like.

Abstract: A splicer for splicing “live” bit streams such as those which carry video programs that have been encoded according to the MPEG-2 standard. The splicer controls the rate at which it outputs the spliced bit stream by means of a model of the receiver and can thereby prevent overflow or underflow in receivers receiving the spliced bit stream. The splicer also includes analyzers for reading the old bit stream and the new bit stream that is to be spliced to the new bit stream. The analyzers provide information to the receiver model and also permit the splicer to select IN and OUT points in the old and new bit streams that minimize the effect of the splice on the decoding of the bit stream done in the receiver. Where necessary, the splicer modifies the output bit stream to reduce interference with decoding. The splicer does not require splice parameters to select IN and OUT points or to determine the proper bit rate or the spliced bit stream.

Abstract: A method and apparatus for an adaptive quantization control is disclosed. The present invention decomposes one picture into a plurality of blocks, encodes the picture in the block unit and controls quantization by obtaining a first activity from a comparison of the activity of the current block to be encoded and that of the entire blocks; obtaining a second activity from a comparison of motions of neighboring blocks; and controlling the quantization using the first activity if the first activity is below a reference value and using the second activity if the first activity exceeds the reference value.

Abstract: A coder of the present invention is adapted to reproduce a signal of quality at a low coding rate even when a video or audio signal continuously supplied thereto should be coded in real time. The coder includes: a quantizer for quantizing the input signal; an encoder for encoding the output of the quantizer and outputting coded data; and a quantization parameter supply circuit for supplying a quantization parameter to the quantizer. If a scene change detector has detected a scene change, the supply circuit supplies a quantization parameter, which has been determined adaptively to a scene newly appearing after the scene change, to the quantizer. Otherwise, the supply circuit supplies a quantization parameter, which has been determined at such a value as to stabilize a coding rate, to the quantizer. In this manner, an average coding rate can be controlled and coding processing can be performed adaptively to individual scenes.

Abstract: A picture analyzer detects coding difficulty information by analyzing the source picture data. A picture converter converts the format of the source picture data using spatial conversion or temporal conversion, or both. A coding unit then codes the converted picture data output from the picture converter. A preprocess controller controls the picture converter based on the coding difficulty information, selecting either spatial conversion or temporal conversion, or both. The resulting encoded picture features visually outstanding image quality in which block distortion is not conspicuous, and the coding unit avoids using a coarser than necessary quantization step even when the bit rate is low.

Abstract: A controller allocates a bit size for a current frame in a group of pictures of a first compression-encoded digital video signal that is to be spliced following transmission of the group of pictures with a second compression-encoded digital video signal. The signals are spliced after a predetermined switching time. The spliced signals are buffered by a decoder buffer and then decoded by a decoder. When the second signal has a variable bit-encoding rate and the current frame is not decoded until after the predetermined switching time, the maximum bit size is determined in accordance with an estimate of the decoder buffer fullness at the predetermined switching time. When the second signal has a predetermined maximum variable bit-encoding rate and the current frame is not decoded until after the predetermined switching time, the minimum bit size is determined in accordance with the predetermined maximum bit-encoding rate of the second signal.

Abstract: This invention relates to improvements in compressing digital signals, particularly in buffer management prior to transmission.

Abstract: An encoding apparatus including a block forming unit for dividing an input signal into blocks each consisting of a plurality of sample values, an orthogonal conversion unit for orthogonally converting the input signal blocks, a detection unit for detecting the characteristic of each block in accordance with orthogonal conversion coefficients obtained by the orthogonal conversion unit, a selection unit for selecting optimal quantization parameters which can realize a constant code amount obtained when the input signal blocks are encoded in a unit consisting of a plurality of input signal blocks, a changing unit for changing the quantization parameters selected by the selection unit in accordance with an output from the detection unit, and an encoding unit for encoding the orthogonal conversion coefficients from the orthogonal conversion unit using the quantization parameters changed by the changing unit.

Abstract: A video signal compressing method and a video signal compressing apparatus for compressing a video signal for a system in which for a synchronism between a plurality of compressed signals must be maintained. A presentation time stamp and/or a decode time stamp are multiplexed in a stream for transmission in which a video signal is compressed to generate a compressed signal. The following are generated as access unit information (AUI) for use in multiplexing the compressed data of the video signal: a picture size value, a picture type value, a repeat first field value, and a flag indicating the occurrence of a big picture.

Abstract: A system for playing a selected one of multiple audio tracks recorded in synchronized fashion with a motion picture on an optical disk. The optical disk has encoded on it a mixing master music and effects (“M&E”) track, or a switching master M&E track. Individual audio tracks are provided for language-specific versions of the same motion picture, but these tracks have data recorded in them only where there is dialog. In this way, for many a motion picture, all tracks but masters will have data recorded for well less than half of the running time of the motion picture. When a mixing master is used, it is mixed with a language-specific track when the latter has dialog; the mixing master contains no dialog. If a switching master is used, it may contain dialog recorded with the M&E; when a language-specific track has dialog recorded in it, it also contains M&E and the track is played to the exclusion of the switching master.

Abstract: A motion factor coding apparatus receives an input video signal which is applied to a subtractor and to a motion estimator which generates motion vectors for the current frame relative to a reference frame that is stored in the motion estimator. The motion vectors are passed to a buffer which are then iteratively update in a re-estimator. The number of iterations can be set to a fixed number or can be controlled by measuring the effect of each successive update on the motion. When a satisfactory number of iterations is reached, update motion vectors are passed to a motion compensator which generates a predicted frame which is applied as another input to the subtractor where the predicted frame is subtracted from the current frame in the input digital video signal. The subtraction removes temporal redundancy in the signal.

Abstract: An apparatus and a method of encoding/decoding an input image frame in an image data processing system are disclosed. Using the apparatus and the method of the present invention, a total memory space of the memories required for encoding/decoding the input image frame is optimized using a slice memory. The encoder/decoder according to the present invention includes a slice memory storing each image slice of a restored image frame having T image slices and a first frame memory storing the restored image frame by copying each image slice stored in the slice memory until all of the T image slices are copied.

Abstract: In a moving image encoding device, a first object encoding section encodes first object data within a unit time allowable code amount and outputs the resultant, data and a first object generated code amount. A code amount log storage section stores the first object generated code amount. A remaining object allowable code amount calculating section adds up the first object generated code amount within each time interval to obtain a sum, and subtracts the sum from the unit time allowable code amount to calculate a remaining object unit time allowable code amount. A second object encoding section encodes each VOP of second object data in accordance with a second object VOP target code amount, and outputs the resultant data, second object encoding information including quantization information, motion information, activity information, encoding error information, or object size information, and a second object generated code amount.

Abstract: The present invention provides an apparatus and method for coding moving pictures, which reduces a delay time generated by buffering of a decoding apparatus in compressive coding of the moving pictures. In this invention, the target number of bits of one picture P as a target value of the number of generated bits per one picture is set as well as the upper limit number of bits uCg as an upper limit value of the number of generated bits of the picture is set. Then, when the cumulative number of generated bits Cg generated from the first macroblock to a macroblock which is being coded in the picture exceeds the upper limit number of bits uCg in the middle of the picture which is being coded, the coding of a macroblock is skipped to avoid underflow.

Abstract: A method for processing image data includes quantizing a region in a frame with an initial quantizer level. It is determined whether an amount of bits required for encoding the region after quantizing the region with the initial quantizer level is within a bit allocation budget. The region is re-quantized if the amount of bits is not within the bit allocation budget.

Abstract: A method of compressing digital data is disclosed including the steps of transforming the data utilizing a discrete wavelet transform to produce corresponding transformed data; quantizing the transformed data utilizing a variable quantization determined by a corresponding quadtree structure wherein each of the quadtree leaf nodes has an associated quantization factor utilized in the quantizing of the transformed data. Preferably, the quadtree is determined to be an optimum in a rate distortion sense and encoded utilizing a binary prefix notation followed by a list of quantization factors. The method of Lagrange multipliers can be utilized to determine the optimum to a predetermined number of bits per data item. The present invention has particular application to image data or to video data and in particular frame difference data.

Abstract: In a coding control apparatus deciding, when coding of motion picture data on the basis of a generated information amount Aig of coded data generated by coding one frame, a quantization characteristic to be used for coding a next frame, a threshold comparison part compares the generated information amount Aig with upper bound and lower bound thresholds Th_U and Th_L, and on the basis of the comparison result, a quantization characteristic decision part decides the quantization characteristic to be used for coding the next frame.

Abstract: Input picture data represents a succession of pictures each composed of plural blocks. The input picture data is quantized into first quantization-resultant data in response to a fixed quantization width. The first quantization-resultant data is encoded into first code data of a variable length code for every block. Information of an accumulation transition in an amount of the first code data is generated for every block. A code amount accumulation transition value is calculated from the accumulation-transition information and a predetermined target code amount for every block. The predetermined target code amount is defined with respect to every picture. The input picture data is quantized into second quantization-resultant data in response to a variable quantization width. The second quantization-resultant data is encoded into second code data of the variable length code for every block. An actual amount of the second code data is detected for every block.

Abstract: An MPEG encoder for encoding an input digital video signal performs encoding processing in every macroblock forming a picture by a frame sequence changing unit, a motion detecting unit, a subtracting unit, a discrete cosine transform unit, a quantization unit, a variable-length coding unit, an inverse quantization unit, an inverse discrete cosine transfer unit, an adding unit, a frame storing and predicting unit, a multiplexer, and a buffer memory. The encoder further decides a quantization scale for every macroblock by a quantization deciding unit by use of the picture target encode amount calculated in an assigned encode amount calculating unit and the encoded amount obtained in an encoded amount calculating unit, and thereafter controls the quantization scale to be corrected into a direction of decreasing a deviation degree of the encoded amount from the target encode amount by a quantization correcting unit.

Abstract: Executes a re-encoding after decoding data of a connection section A of a first MPEG picture data. This re-encoding is executed based on a control such that a transition of a VBV buffer occupation value starts from a VBV buffer occupation value at a position a and ends with a VBV buffer occupation value at a position d. Up to the position a of the first MPEG picture data, the first MPEG picture data is reproduced. Next, re-encoded MPEG picture data of the connection section A is reproduced. Thereafter, the data is connected to the position d of a second MPEG picture data, and the second MPEG picture data of the position d and after is reproduced.

Abstract: A system and method for performing image compression using multi-threshold wavelet coding (MTWC) which utilizes a separate initial quantization threshold for each subband generated by the wavelet transform, which substantially reduces the number of insignificant bits generated during the initial quantization steps. Further, the MTWC system chooses the order in which the subbands are encoded according to a preferred rate-distortion tradeoff in order to enhance the image fidelity. Moreover, the MTWC system utilizes a novel quantization sequence order in order to optimize the amount of error energy reduction in significant and refinement maps generated during the quantization step. Thus, the MTWC system provides a better bit rate-distortion tradeoff and performs faster than existing state-of-the-art wavelet coders.

Abstract: In the case where the code generation volume that the data occupancy rate in the buffer of the image decoding apparatus is smaller than the first, second or the third threshold value corresponding to the first, second or the third image currently being coded from among the first, second and third threshold values of the data occupancy rate set corresponding to the first image to be intra-coded, the second image to be directionally predictive coded and the third image to be bidirectionally predictive coded respectively, the coding processing on the first, second or the third image presently being coded will be stopped.

Abstract: A rate control apparatus for real-time video communication includes: an initialization unit for setting an initial value required for rate control according to a transmission speed and the number of input frames; a target bit calculation unit for obtaining the target number of encoding bits, maximum allowable number of bits, and minimum allowable number of bits in consideration of a buffer state and a transmission speed; a rate control and encoder unit for executing rate control and encoding using the maximum allowable number of bits and the minimum allowable number of bits; a stuffing control unit for comparing the size of a bit stream from the rate control and encoding unit with the target number of encoding bits from the target bit calculation unit for thereby outputting stuffing bits; a buffering unit for storing a combination of the bit stream from the rate control encoding unit and the stuffing bits from the stuffing control unit for thereby outputting them to the target bit calculation unit; a frame sk

Abstract: Disclosed is a picture encoding format converting apparatus, comprising: a picture decoder for decoding a picture signal from an input bitstream; a picture encoder for encoding the picture signal into an output bitstream; a main controller for controlling the amount of calculations executed by the picture encoder, on the basis of a state of the picture decoder.

Abstract: An encoding apparatus comprises an input unit for supplying sampled information data, a block forming unit for forming blocks of the information data supplied by said input means, an encoding unit for encoding information data outputted from said block forming unit, a detection unit for detecting code quantity of encoded data derived by consolidating and encoding said blocks, a one-dimension processing circuit for a applying one-dimension processing to the encoded data of said blocks, and a deletion unit for deleting the encoded data in accordance with the enocded data processed by said one-dimension processing circuit in accordance with the output of said detection unit.

Abstract: A method and system for encoding digital video picture data. In accordance with this method, the video picture data is partitioned into a group of blocks, at least some of those blocks are selected, one block at a time, and each of the selected blocks of data is encoded to form an encoded coefficient having an associated number of bits. The encoded coefficients are outputted, and an accumulated sum of the number of bits in the outputted encoded coefficients is kept. The outputting of the encoded coefficients is terminated at a defined time in order to prevent the accumulated sum from exceeding a given number.

Abstract: In accordance with a first embodiment of the invention, a method for editing video is provided. In accordance with the invention, a previously compressed first digital video bit stream is decoded to obtain a decoded digital video signal. In response to statistical values which characterize the previously compressed first digital video bit stream, the decoded digital video signal is re-encoded to form a second digital video bit stream such than an ending fullness of a vbv does not fall below a predetermined threshold. Optionally, an effect may be added to the decoded digital video signal before re-encoding. A second embodiment of the invention is directed to a method for splicing a first compressed digital video bit stream and a second compressed digital video bit stream. The first compressed digital video bit stream has a plurality of entry points.

Abstract: A system for coding video data comprised of one or more frames codes a portion of the video data using a frame-prediction coding technique, and generates residual images based on the video data and the coded video data. The system then codes the residual images using a fine-granular scalability coding technique, and outputs the coded video data and at least one of the coded residual images to a receiver.

Abstract: The invention relates to a transcoding method and device for converting input coded signals previously quantized with a first quantization scale Q1 into output coded signals quantized with a second quantization scale Q2.

Abstract: A data compression device for correctly allotting limited amounts of data and performing high image quality compression of video data by means of a method suitable for an authoring device such as the MPEG (Moving Picture Experts Group) technique so that when the desired amount of data for compression is set based on the data quantity detected by the previous data compression processing, the target bit quantity is set in specified block units, allotted to separate frames and then corrected by means of the individual block structure.

Abstract: A system for encoding data blocks and methods of operating the same result in a video encoder that provides advanced intelligent encoding. The video encoder comprises DCT (discrete cosine transformer) resources configured to DCT the data blocks. Quantizing resources is coupled to the DCT resources configured to quantize the data blocks to provide quantized data blocks. Inverse quantizing resources is coupled to the quantizing resources to inverse quantize the quantized data blocks. Frame reconstruction resources is coupled to the inverse quantizing resources configured to reconstruct previous compressed frames. Motion estimation resources is coupled to the frame reconstruction resources configured to provide predicted data blocks. Subtraction resources is coupled to the DCT resources and the motion estimation resources to subtract the data blocks and the predicted data blocks.

Abstract: The present invention provides an apparatus and method for coding moving pictures, which reduces a delay time generated by buffering of a decoding apparatus in compressive coding of the moving pictures. In this invention, the target number of bits of one picture P as a target value of the number of generated bits per one picture is set as well as the upper limit number of bits uCg as an upper limit value of the number of generated bits of the picture is set. Then, when the cumulative number of generated bits Cg generated from the first macroblock to a macroblock which is being coded in the picture exceeds the upper limit number of bits uCg in the middle of the picture which is being coded, the coding of a macroblock is skipped to avoid underflow.

Abstract: A transmission system which quantizes a data signal into quantized data and alternatively either transmits the quantized data while controlling a quantity of distortion to a constant value or transmits the quantized data while controlling a quantity of data generated to a constant value as a function of the quantized data which are alternatively stored in and read out from a first memory and a second memory.

Abstract: An image transmitting system which maintains the same image resolution even when a line speed is set to a low speed. The image transmitting system basically comprises an image data conversion block, a quantization block, a variable-length coding block, smoothing buffers, output selectors, and a dequantization block. The image data conversion block converts input image data into a coefficient suitable for coding. The quantization block quantizes the coefficients obtained through conversion. The variable-length coding block codes the quantized coefficients. The first smoothing buffer smoothes the generated amount of data with respect to a first frame in a block, the second smoothing buffer smoothes the generated amount of data with respect to a second frame in the block, and the third smoothing buffer smoothes the generated amount of data with respect to a third frame in the block.

Abstract: An upper limit of a usable range of a VBV buffer is determined from a preset delay time of the VBV buffer and a designated bit rate. A target bit quantity of a picture (i) and a data occupancy quantity of the VBV at the time when a picture (j+1) is coded are calculated, and the target bit quantity T(j) for coding the picture (j) is corrected so that the data occupancy quantity of the VBV of the picture (j+1) constantly falls within the limited range. By this, even when a low coding bit rate is set, the delay due to the VBV buffer of a predetermined delay time or longer does not reach a prescribed delay time or longer. Thus, an MPEG encoder suitable for a live broadcast in which the problem of delay time is not desired can be realized.

Abstract: Plural n number of encoders 21, 22 . . . 2n carry out reading in advance of parameter information PAR. #1, #2 . . . #n with respect to respective n number of programs prog. 1, 2 . . . n to allow a controller 3 to estimate encoding difficulty related information “difficulty” when picture is encoded, and to compression-encode the plural n number of programs on the basis of target encoding rate that the controller 3 has calculated on the basis of the parameter information. The controller 3 calculates allocation code quantities target_rate #1, #2 . . . #n every respective programs from the parameter information PAR. #1, #2 . . . #n. A multiplexer 4 multiplexes streams “stream” #1, #2 . . . #n that the encoders 21, 22 . . . 2n have encoded in correspondence with the allocation code quantities target_rate #1, #2 . . . #n.

Abstract: A video encoder for changing the bit rate at a halfway point in a GOP by using a TM5 (Test Model 5) bit rate control algorithm is provided. Using a bit quantity Rj(+1) allocated to non-coded pictures at and after a coding target picture (j+1), a target bit quantity T(j+1) allocated to the coding target picture (j+1) is calculated. In the case where pictures up to a picture (j) at a halfway point in a GOP are coded at a first bit rate and the picture (j+1) is coded at a second bit rate, the bit quantity R(j+1) allocated to non-coded pictures for calculating the target bit quantity R(j+1) is corrected to a bit quantity R(j+1) for non-coded pictures at the time when the pictures from a leading picture of the GOP are coded at the second bit rate. Thus, seamless bit rate change can be carried out at a halfway point in the GOP by using the fixed rate algorithm such as TM5.

Abstract: A method and apparatus for achieving maximum bandwidth reduction in communication networks. The invention provides a multisource coding scheme, implemented through an intersource coding block that provides maximum bandwidth reduction for transmissions from a plurality of time-correlated information sources over a single physical link. In one embodiment of the invention the intersource encoder uses run-length coding to compress the aggregate bit rate before the physical transmission. The intersource encoder provides data compression for both completely correlated and partially correlated sources. For completely correlated sources, the intersource encoder strips off the intersource redundancies and transmits only a single copy of the information over the physical link, wherein the single copy is a superpicture. For partially correlated sources, the intersource encoder compresses the aggregate signal through a predetermined coding scheme, including vector run-length coding.