Abstract: A predictive video coder performs gradient prediction based on previous blocks of image data. For a new block of image data, the prediction determines a horizontal gradient and a vertical gradient from a block diagonally above the new block (vertically above a previous horizontally adjacent block). Based on these gradients, the encoder predicts image information based on image information of either the horizontally adjacent block or a block vertically adjacent to the new block. The encoder determines a residual that is transmitted in an output bitstream. The decoder performs the identical gradient prediction and predicts image information without need for overhead information. The decoder computes the actual information based on the predicted information and the residual from the bitstream.

Abstract: The present invention relates to a filter circuit for a set of original data (X0-X7) able to implement in series the steps of discrete transformation (DCT2), correction (ZER) of odd transformed data and inverse discrete transformation (IDCT2). The filter circuit takes advantage of the fact that the paths corresponding to the even and odd transformed data are completely separate with the exception of a first processing stage (ST1) of the discrete transformation and a last processing stage (ST8) of the inverse discrete transformation in order to connect a first half of the data issuing from the first stage to the last processing stage. The implementation of the filter circuit is thus simplified, both making said circuit less expensive and giving it a lower power consumption. For optimized implementation, the filter circuit functions in differential mode.

Abstract: The present invention provides a method of supplementing a digital picture with a shorter delay time and less calculations. The padding method is applied to a picture having a great motion, and results in producing a prediction signal with small errors. The present invention also provides an apparatus using the same method. To be more specific about the method, in a digital picture data including picture information indicating an object, a picture is resolved into a plurality of regions adjoining with each other, and each of the insignificant sample value of a region containing the boundary of the object shape is supplemented (padded) by the values obtained from transforming of the significant pixels near to the insignificant pixels.

Abstract: The process is characterized in that it performs the inverse operations (26, 27, 28) of the successive coding operations, in an inverse order, coefficient by coefficient rather than block by block.

Abstract: An MPEG decoding system selectively decodes MPEG enhanced streams, based on a select identification of an enhancement region of a series of image frames. MPEG blocks within the enhancement region are decoded with the enhancement-layer, while blocks outside the enhancement region are decoded at the base-layer. Additionally, the user is provided the option of displaying the series of images in a window that is selectively sized to contain only the enhancement region, or the enhancement region surrounded by a base-layer region, or a custom sized window that may include all or some of the enhancement and base-layer regions.

Abstract: Method and apparatus for performing data conversion between first-format encoded data in which orthogonal transform coefficients are arranged in an order of DC components and AC components from a low spatial frequency order to a high spatial frequency order in each orthogonal transform block when compression encoding which includes orthogonal transform is applied to video data and second-format encoded data in which orthogonal transform coefficients are arranged in an order of DC components and AC components from a low spatial frequency order to a high spatial frequency order in each block assembly member formed of a plurality of orthogonal transform blocks when compression encoding which includes orthogonal transform is applied to video data. The second-format encoded data may be decoded to obtain orthogonal transform coefficients which may be re-arranged from a low spatial frequency order to a high spatial frequency order in each orthogonal transform block of the first format.

Abstract: An apparatus has a one-dimensional DCT transformer (101) for applying the one-dimensional orthogonal transforms to n inputs and outputting n coefficients, a transposition converter (102) for transposing n×n coefficients output from the one-dimensional DCT transformer (101) and outputting every n outputs, a multiplexer (103a) for selecting one output (1004a) of the n outputs from the transposition converter (102) or one output (1003a) of the n outputs from the one-dimensional DCT transformer (101), and a selector (100) for selecting data as a combination of one output (1010a) selected by the multiplexer (103a) and remaining (n−1) outputs, which are not input to the multiplexer (103a), of the n outputs from the transposition converter (102), or the input image data, and supplying the selected data as n data to the one-dimensional DCT transformer (101).

Abstract: The invention provides a method for coding an output bitstream of an input video so the decoded output bitstream has a constant perceived quality. A base layer bitstream having a constant bit-rate is generated from the input video, and an input enhancement layer bitstream is generated from a difference between the input video and the base layer bitstream. Alternatively, the base and input enhancements layer bitstreams are pre-stored.

Abstract: A video reception device, such as personal computer, generates high quality video from video data received from a video capture device over a low data rate communication interface such as a USB interface. The video data is received by the reception device in two passes. The first pass provides a low frequency portion of coefficients and the second pass provides a high frequency portion of coefficients. The coefficients representing the video are generated by performing a Discrete Cosine Transform (DCT) on blocks of pixels and compressing a portion of the coefficients. In one embodiment, the video reception device matches a frame received during the first pass with a frame received during the second pass and signals the video capture device to switch from compressing the low frequency portion of coefficients to compressing the high frequency portion.

Abstract: The present invention provides an improved motion estimation encoder for digital video encoding applications. In one example embodiment, the improved encoder receives a raw image in the form of a current frame and estimates the macroblock motion vector with respect to a reference frame. The encoder then performs an initial local search around an initial motion vector candidate derived from spatio-temporal neighboring macroblock parameters. The encoder then compares the user-defined complexity scalable sum of absolute difference between the original and the associated reference macroblock against an adaptive threshold value for motion estimation convergence. The encoder introduces a global full search around a candidate from a coarser level, in case an initial local search fails.

Abstract: Adjacent regions are identified in an image. Coding parameters for the adjacent regions are identified. Selective filtering is performed at the region between the identified adjacent regions.

Abstract: This invention solves problems due to employing error degraded data in digital processing. It particularly solves multi-generation problems wherein transform data degrade during each inverse transform and forward transform cycle even without any processing due to the rounding and clipping errors. It provides methods, systems and devices for reduced-error processing of transform-coded data. After inverse transformation of transform data, high-precision numbers are converted to integers and clipped to an allowed range forming converted data. High-precision differences are obtained by subtracting the high-precision output of the inverse transform from the converted data. The converted data can be manipulated and sent to output devices which expect integer data. Processed high-precision numbers are formed by adding the high-precision differences to the processed converted data. Thus, the rounding and clipping errors are greatly reduced in the processed high-precision numbers.

Abstract: A distributed video stream decoding system on computer and decoding method of the system is proposed to increase the decoding efficiency. The decoding method reads pictures of video stream and divides each picture into a plurality of slice packages through software modules executing on a CPU. Then, the method dispatches the slice packages by slice dispatcher and sends at least a slice into a master decoder when the slice queue of the master decoder less then a default value and sends a slice into a secondary decoder when the secondary decoder is waiting, respectively. Therefore, the master decoder and the secondary decoder can decode the received slice simultaneously to increase the decoding efficiency.

Abstract: A video transcoding method and apparatus enables digital video to be transmitted over various network infrastructures by transcoding video data to fit available bandwidth. A transcoder extracts MPEG video data from the video stream wrapper and decomposes the MPEG layered data to the block level. The transcoder then processes the variable length coding (VLC) of discrete cosine transform (DCT) coefficients without having to decode and re-code the video stream. Processing involves assigning an allowable error range to each DCT frequency in the video stream based on the available network bandwidth and/or the effect of the DCT code on perception of picture quality, and adapting video traffic dynamically by changing large length codes to small length codes based on the assigned allowable error range. The larger the allowable error ranges that are assigned to the DCT frequencies, the more video traffic may be trimmed off from the incoming video stream.

Abstract: When repeatedly performing compression and encoding of video data, automatically detecting a previous picture type at an encoder side and performing the compression and encoding by matching GOP phases.

Abstract: A variety of different types of video frame encoders can be configured with, e.g., a multimedia processing subsystem, as long as the video frame encoder conforms to the interface protocol of the subsystem. A video controller in the subsystem performs the higher-level functions of coordinating the encoding of the video stream, thereby allowing the video frame encoder to limit its processing to the lower, frame level. In particular, the video controller provides information needed by the video frame encoder to encode the current frame in the video sequence. In addition to the raw image data, this information includes the type of frame to be encoded (e.g., an I or P frame), the currently available bandwidth for encoding the current frame, the time since the previous encoded frame, the desired frame rate, and a quality measure that may be used to trade off spatial and temporal qualities.

Abstract: In a transcoder means are provided for implementing a simultaneous change in rate and in resolution. In a preferred embodiment means are also provided for transferring incoming motion vectors or the like directly to the output encoder. The transcoder architecture is both suited for implementation in the spatial as well as in the frequency domain.

Abstract: A method of transcoding an input image bit stream into an output image bit stream having a different bit rate. The method includes determining a cut area of an input image to be removed, cutting the input image according to the cut area, and generating an output image of the output image bit stream corresponding to the input image after the cutting. In the present method, image areas of not interest to a user are removed so as to lower the bit rate. In addition, removed bits are reassigned to concern areas so as to improve a picture quality.

Abstract: A drift reduction method and apparatus. Drift reduction is effected in an MPEG video transcoder by decoding dropped out pixels to form a drift reference frame. The quantization indices in the current macro-block are changed accordingly in a drift reduction process. The compensated quantized frame is then variable length coded to an MPEG bitstream.

Abstract: A method of data compression. A multiple-level wavelet transform transforms image data of an original image. Motion compensation is performed on a low-frequency band of the transformed image data. This band is then inversely transformed and used to reconstruct a portion of the original image. The remaining portions of the original image are then reconstructed from that portion. This image data then becomes the basis of the next level of the wavelet transform and is transformed back into the wavelet domain. This process is repeated until all of the levels of the wavelet transform have been used.

Abstract: An apparatus and method for encoding quantized frequency represented data, the data comprising zero and non-zero represented data is claimed. For zero represented data, a zero run length is determined. A Golomb parameter is determined as a function of the zero run length. A quotient is encoded as a function of the zero run length and the Golomb parameter. A remainder is encoded as a function of the zero run length, the Golomb parameter and the quotient. The coded quotient and the coded remainder are concatenated. For non-zero represented data, the nonzero data is encoded as a function of the non-zero data value and the sign of the non-zero data value.

Abstract: The present invention is directed to decoding a video bitstream at a first resolution where embedded resizing is used in conjunction with external scaling in order to reduce the computational complexity of the decoding. According to the present invention, residual error frames are produced at a second lower resolution. Motion compensated frames are produced also at the second lower resolution. The residual error frames are then combined with the motion compensated frames to produce video frames. Further, the video frames are up-scaled to the first resolution.

Abstract: A method transcodes groups of macroblocks of a partially decoded input bitstream. The groups of macroblocks include intra-mode and inter-mode macroblocks. Each macroblock includes DCT coefficients, and at least one motion vector. The modes of each group of macroblocks are mapped to be identical only if there is an inter-mode block and an intra-mode macroblock in the group. If any of the macroblocks in the group are mapped, then the DCT coefficients and the motion vector for such mapped macroblocks are modified in accordance with the mapping to generate reduced-resolution macroblock for an output compressed bitstream to compensate for drift.

Abstract: A multi-channel image encoding apparatus for selectively receiving image signals transmitted through a plurality of input channels and encoding the image signals. The multi-channel image encoding apparatus includes a channel data processor that has a frame buffer group having a plurality of frame buffers for each input channel in order to receive a plurality of frame data through the plurality of input channels and to store the plurality of frame data, the channel data processor for selecting the data transmitted to the frame buffer group to output the selected data, and an encoder for encoding image signals output from the channel data processor with an MPEG method.

Abstract: System and method are provided for optimally encoding a sequence of video frames using image statistics collected from multiple encoders connected in parallel, each encoder employing a different set of encode parameters. The image statistics are used to select an optimum set of encode parameters for use in encoding the sequence of video frames in a subsequent encode subsystem stage. As an alternative, multiple buffers are connected to the outputs of the multiple, parallel connected encoders, with the encoded stream from the encoder employing the optimum set of encode parameters selected for output as the bitstream of encoded video data.

Abstract: The present invention provides a method of and system for determining whether a local area of a compressed video stream represented by a plurality of DCT encoded blocks subject to decoding and filtering/scaling is a stationary area or an interlaced moving area. Further, given such information, the invention relates to dynamically switching between frame- or field-based operations in a smart way, thus optimizing the output picture quality. Also, a DCT-domain-filtering scheme for field-based filtering/scaling of frame-DCT data is provided herein.

Abstract: New and improved apparatus and methods for video encoding, for example, to efficiently and concurrently encode video data into digital formats, such as Digital Video (DV) format. A pipelined system receives a block of video data and based on the computations and comparisons concurrently performed on the pixels within the block of video data determines which type of transformation is most appropriate for a given block of video data.

Abstract: A system and method for performing an inverse discrete cosine transform (IDCT) based on DCT data is disclosed. The system is IEEE compliant and transforms one block (8×8) of pixels in 64 cycles. The IDCT processor receives the DCT input, produces the matrix (QXTQ)P, or XQP, in IDCT Stage 1 and stores the result in transpose RAM. IDCT Stage 2 performs the transpose of the result of IDCT Stage 1 and multiplies the result by P, completing the IDCT process and producing the IDCT output. The system performs the matrix function QXtQ, where X represents the DCT data and Q is a predetermined diagonal matrix. The resultant value is adjusted by discarding selected bits, and the system then postmultiplies this with the elements of a predetermined P matrix, and discards selected bits. The system performs a conversion and storing function and performs a sign change to obtain QXtQP. This completes first stage processing, which is then passed to transpose RAM.

Abstract: Systems and methods for transcoding a transport stream or a video stream. A video stream includes a quantization matrix and a quantization scale that define how DCT frequency coefficients are quantized. A transport stream is transcoded by updating the quantization matrix and/or the quantization scale such that a new set of DCT frequency coefficients may be generated. Typically the quantization scale and/or the quantization matrix are updated such that the DCT frequency coefficients are more coarsely quantized such that their encoding consumes fewer bits. The quantization matrix can be updated such that select frequency coefficients are affected. Transcoding can operate at any level of the video stream, such as the frame level, the slice level, or the macroblock level. The bit rate of the video stream can therefore be adjusted or altered according to a current quantization level and a current bit rate.

Abstract: The present invention relates to a device for processing blocks of coded data included in a sequence of coded digital images (ES) according to a block-based coding technique, said device comprising a post-processing circuit DFD (33). Such a device effectively corrects the blocking artifacts while minimizing the bandwidth used, the decoder directly transmitting decoded data blocks (B) to the post-processing circuit. In addition, such a device introduces no or little drift during the decoding since the decoder continues to use reference images (RB) during a motion compensation step. This is because the reference images are no longer the decoded images but the completely processed images as the post-processing circuit is situated in the decoding loop.

Abstract: An apparatus and method of transcoding a video snap image is disclosed. The apparatus includes a video decoder for performing a variable length decoding (VLD), inverse discrete cosine transform (IDCT), and inverse quantization with respect to an input bit stream to display the decoded bit stream, a DC extraction section for extracting DC components from discrete cosine transform (DCT) coefficients of variable-length-decoded macro blocks, an adder for averaging the extracted DC components, a differential pulse code modulation (DPCM) section for obtaining and outputting a difference value between the DC component averaged by the adder or the DC component outputted from the DC extraction section and a DC component of a previous macro block, a Huffman encoding section for Huffman-encoding the difference value outputted from the DPCM section, and a storage device for storing a Huffman-encoded snap image and the video bit stream.

Abstract: Transcoding of a video stream to reduce the size of the video stream with little, if any, loss in video quality after subsampling. After accessing a video stream of video pictures (i.e., video frames or fields), the blocks of the video picture are each subject to matrix pre-multiplication and post-multiplication. Such matrix multiplication does degrade the video quality if subsampling was not to occur. However, the pre-multiplication and post-multiplication matrices are calculated based on the subsampling matrices that will be used to ultimately subsample the video stream such that after subsampling eventually occurs, the matrix multiplications result in minimal loss of video quality.

Abstract: A hybrid video encoder which carries out motion estimation and compensation (8) in the transform domain. In such an encoder, the calculation of a prediction block (Ŷ) from previously encoded blocks (Z) stored in the transform-domain frame memory (7) requires a large number of multiplications. This applies particularly to the motion estimation algorithm. In accordance with the invention, only a few DCT coefficients of candidate prediction blocks are calculated, for example, the DC coefficient and some AC coefficients. In a preferred embodiment, the AC coefficients are adaptively selected in dependence upon the motion vector which is being considered. The calculated coefficients of the candidate prediction blocks and the corresponding coefficients of the current input picture block (Y) are then compared to identify the best-matching prediction block.

Abstract: A DMT system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional DMT systems. The DMT system and method provide seamless rate adaptation with the provision of different power levels. This framing and encoding method enables a system with seamless rate adaptation capability. The system and method of the invention can be implemented in hardware, or alternatively in a combination of hardware and software.

Abstract: Data compression and decompression methods for compressing and decompressing data based on an actual or expected throughput (bandwidth) of a system. In one embodiment, a controller tracks and monitors the throughput (data storage and retrieval) of a data compression system and generates control signals to enable/disable different compression algorithms when, e.g., a bottleneck occurs so as to increase the throughput and eliminate the bottleneck.

Abstract: In a system for encoding digital video, a method of interframe coding is described. A sequence of digital video frames may be expressed as anchor frames and at least one associated subsequent frame. The plurality of pixels of the anchor frame and each subsequent frame are converted from pixel domain elements to the frequency domain elements. The elements are quantized to emphasize those elements that are more sensitive to the human visual system and de-emphasize those elements that are less sensitive to the human visual system. The difference between each quantized frequency domain element of the anchor frame and corresponding quantized frequency domain elements of each subsequent frame are determined and encoded.

Abstract: Adaptive compensation for requantization. A reference picture is decoded. Another copy of the reference picture is then requantized and then decoded. Next, an error picture is calculated and stored. The error picture represents the difference between the reference picture as decoded without requantization and the reference picture as decoded with requantization. The error picture and the requantized reference picture are used to generate a predictive picture that at least partially compensates for generational error introduced by requantization. This compensation for error may be adaptively performed based on system conditions.

Abstract: A device for image encoding and decoding is implemented as follows. There is an incomplete encoding circuit (ENCI) for effecting, inter alia, a DCT transform, a quantization and a variable-length encoding. There is an incomplete decoding circuit (DECI) for effecting, inter alia, a variable-length decoding. Moreover, there is a complementary circuit (CC) for effecting, inter alia, an inverse quantization, an IDCT transform and a motion compensation. A control circuit (CTRL) enables the complementary circuit (CC) to cooperate with the incomplete encoding circuit (ENCI) and the incomplete decoding circuit (DECI) in order to effect encoding and decoding, respectively. The complementary circuit (CC) is arranged to operate in accordance with different modes of an encoding standard. Accordingly, the incomplete decoding circuit (DECI) and the complementary circuit (CC) can, in combination, decode recordings which have been made in accordance with different modes of an encoding standard.

Abstract: A method of decimation of a digital image, the digital image represented by a plurality of pixels, is claimed. In the pixel domain, the digital image is divided into a plurality of blocks. Certain ones of the blocks are selectively decimated base upon predetermined criteria. In an embodiment, the chrominance portions of a give pixel block are determined.

Abstract: A moving picture coding/decoding method and apparatus having a spatially scalable architecture and a signal-to-noise ratio (SNR) scalable architecture together is provided.

Abstract: A method up-samples a compressed bitstream. The compressed bitstream is partially decoding to produce macroblocks. Each macroblock has DCT coefficients according to a predetermined dimensionality of the macroblock. DCT filters are applied to the DCT coefficients of each macroblock to generate up-sampled macroblocks for each macroblock, there is one up-sampled macroblock generated by each filter. Each generated up-sampled macroblock has the predetermined dimensionality.

Abstract: The present invention relates to a method and a device for monitoring the quality of video data having to undergo coding and decoding, making it possible to maintain predetermined constant quality of the video data after decoding.

Abstract: A system and method for filtering interlaced video in the DCT domain. The invention implements an even length symmetric filter necessary for filtering the bottom field of pixel data using the steps of: decomposing the even symmetric spatial filter design into two identical odd length symmetric filter designs have a one pixel phase difference therebetween; creating a discrete cosine transform (DCT) filter that corresponds to the odd length symmetric filter designs; filtering the field of interlaced video data in the DCT domain using DCT filter to create a set of filtered DCT data; converting the set of filtered DCT data into a set of spatial domain data; and filtering the spatial domain data with a [1,1] filter.

Abstract: A method and apparatus for receiving and processing digitized video data in a discrete cosine transform (DCT) domain exploits the orthogonality of a convolution function along with the data sparseness present in the DCT domain. In a preferred method, the convolution function is applied to vectors associated with a plurality of input video data frames in consideration of an orthogonal characteristic of the convolution function. More specifically, cross-products of the input vectors which would yield non-zero output vectors are identified and weighting factors for the cross-products are determined in consideration of this orthogonality. An output video data frame is generated from the non-zero output vectors and the weighting factors. A convolution operation based upon the disclosed method and aparatus is suitable for chroma-keying as well as other video or audio blending applications.

Abstract: The present invention relates to embedding data in material. Material means one or more of video material, audio material and data material. Video material in this context may be still images or moving images. There is provided an apparatus comprising a transformer for transforming transform domain data into spatial domain data and a combiner for receiving material and combining said spatial domain data with said material to form data embedded material. Hence, the material is not subject any transformation at all.

Abstract: A method compensates for drift in macroblocks of a partially decoded input bitstream. The macroblocks include intra-mode and inter-mode macroblocks, and each macroblock includes DCT coefficients, and at least one motion vector. An estimate of drift is measured in the partially decoded input bitstream. The estimated drift is translated into an intra refresh rate. The modes of inter-mode macroblock are mapped to inter-mode macroblock according to the refresh rate. The DCT coefficients and the motion vector for each changed macroblock are modified in accordance with the mapping for each changed macroblock.

Abstract: A method and apparatus for multi-rate encoding of video sequences. The input data stream is received at a first bit rate. A domain transformation is performed on the input data and the transformed data is encoded into a series of output data streams each with a different bit rate.

Abstract: Left and right video cameras 18L and 18R are disposed on both sides of a front video camera 18M. Solid-pictorial video signals used upon signal transmission are generated by using video signals outputted from the left and right video cameras with respect to a video signal outputted from the front video camera. The left and right video cameras make use of simplified video cameras and are cameras with no zoom functions or the like. The video signals obtained from the left and right video cameras are used as signals for forming a solid picture. In the present example, only solid information with respect to a main picture is transmitted as a video signal to reduce the amount of transmission. Since a motion-compensated DCT encode process using the front video signal as a reference picture is performed to extract only the video signal having the solid information from the left and right video signals. Since the simplified video cameras can be utilized, solid-pictorial video signals can be generated at low cost.

Abstract: In a moving image encoding apparatus of this invention, a generated bit amount extracting section (21) counts generated bits of variable-length-encoded data in units of macroblocks, and a reference generated bit count is set in a parameter value control section (22) as an update condition for a parameter value in each block. The boundary value of the parameter value is set in an intra/inter determination section (23) as a criterion for selection of the intra-encoding mode. In the inter-frame encoding mode, the parameter value control section (22) updates the parameter value of a block in which the generated bit count value of encoded data obtained by the generated bit amount extracting section (21) exceeds a reference value. The intra/inter determination section (23) determines that the influence of a data error is large in a block in which the parameter value is continuously updated and exceeds the boundary value, and switches the current mode to the intra-encoding mode to perform refresh operation.

Abstract: The present invention provides methods and systems to determine the frequency weighting matrix that will provide the best image quality during MPEG4 FGS enhancement layer encoding, and to change this determination on a scene characteristics change basis, thereby optimizing the resulting output picture quality, especially in bandwidth-deprived applications.