Abstract: A coding method for an ordered series of quantized transform coefficients of a block of image data, including a context adaptive position coding process to encode the position of clusters of non-zero-valued coefficients, e.g., a multidimensional position coder that uses one of a plurality of code mappings selected according to at least one criterion including at least one context-based criterion, and an amplitude encoding process to encode any amplitudes remaining to be coded, the amplitude coding using one or a plurality of amplitude code mappings selected according to at least one criterion, including a context-based criterion. A context-based selection criterion is meant a criterion that during encoding is known or derivable from one or more previously encoded items of information. Also a coding apparatus, a decoding apparatus, a computer readable medium configured with instructions that when executed implement a coding method, and another medium for a decoding method.

Abstract: A coding method, apparatus, and medium with software encoded thereon to implement a coding method. The coding method includes jointly encoding joint events that each are defined by a cluster of consecutive non-zero-valued coefficients, each joint event defined by three parameters: the number of zero-valued coefficients preceding the cluster, the number of non-zero-valued coefficients in the cluster, and an indication of which trailing coefficients up to a maximum number of M trailing coefficients have amplitude greater than 1, with the coding using a 3-dimensional joint VLC table. The method further includes encoding the amplitude of the non-zero-valued trailing coefficients that have amplitude greater than 1 encoding the amplitude of any remaining non-zero-valued coefficients in the clusters that have more than M non-zero-valued coefficients.

Abstract: A coding method, apparatus, and medium with software encoded thereon to implement a coding method. The coding method includes encoding cluster of consecutive non-zero-valued coefficients, the encoding of a cluster including jointly encoding joint events that each are defined by at least two parameters: the number of zero-valued coefficients preceding the cluster, and the number of non-zero-valued coefficients in the cluster. The encoding of the cluster also includes encoding a parameter indicative of the number of amplitude-1 trailing non-zero-valued coefficients in the cluster, in one version with the parameter indicative of the number of trailing amplitude-1 coefficients part of the joint events such that the coding is according to a 3-dimensional joint variable length coding table. The method further includes encoding the amplitudes of the non-zero-valued coefficients that are not encoded by the joint encoding, e.g., encoding the amplitudes of the other than the trailing amplitude-1 coefficients.

Abstract: A coding method, apparatus, and medium with software encoded thereon to implement a coding method. The coding method includes encoding the position of non-zero-valued coefficients in an ordered series of quantized transform coefficients of a block of image data, including encoding events using variable length coding using a plurality of variable length code mappings that each maps events to codewords, the position encoding including switching between the code mappings based on the context. The coding method further includes encoding amplitudes of the non-zero-valued coefficients using variable dimensional amplitude coding in the reverse order of the original ordering of the series.

Abstract: Particular embodiments include a method, an apparatus, and logic embodied in tangible computer-readable medium that when executed carries out a method of encoding an ordered sequence of quantized transform coefficients of a block of image data. One embodiment is a context adaptive variable length coding method that includes position coding the positions of zero-valued and non-zero valued coefficients by either a mixed method that encodes either the run length of zeroes preceding a non-zero coefficient or the run length of nonzero-valued coefficients preceding a zero-valued coefficients. Another includes position coding that uses a variable length code for two parameters respectively indicating the number of zero-valued coefficient positions and nonzero-valued coefficient positions still to be coded.

Abstract: An apparatus, a method, and a computer-readable medium having instructions encoded thereon that when executed cause a method to be carried out. The method includes dividing at least a portion of a picture of a video stream into parts of blocks, and processing the parts in parallel by a plurality of interconnected processors. The processing of a respective part by its respective processor includes determining block-level temporal difference features. Each processor also performs coding functions on its respective part of the picture. The method also includes block-level processing using the block-level temporal difference features to determine which blocks in the picture are likely to be that of a face, the block-level processing being at the granularity of at least a block. In one version, the processing in each processor includes edge detection and color segmentation to determine block-level edge features including block-level color-segmented edge features that are then used in the block level processing.

Abstract: An apparatus, a method, and a computer-readable medium having instructions encoded thereon that when executed cause a method to be carried out. The method includes dividing at least a portion of a picture of a video stream into parts of blocks, and processing the parts in parallel by a plurality of interconnected processors. The processing of a respective part by its respective processor includes edge detection and color segmentation to determine block-level edge features including block-level color-segmented edge features. Each processor also performs coding functions on its respective part of the picture. The method also includes block-level processing using the block-level edge features to determine which blocks in the picture are likely to be that of a face, the block-level processing being at the granularity of at least a block.

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 a plurality of ordered sequences of quantized transform coefficients of a corresponding plurality of blocks 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 plurality of blocks include adjacent blocks and form a multi-block partition. The breakpoint location is determined as a function of the sequences of the multi-block partition such that different multi-block partitions can have different breakpoints.

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 properties of neighboring blocks such that little if any information needs to be sent to a decoder about the breakpoint of a block or multi-block partition, and the decoder can use the properties of neighboring blocks to determine the breakpoint used to code a to-be-decoded sequence or sequences of a block or a multi-block partition.

Abstract: A method, and apparatus, and logic encoded in one or more computer-readable tangible medium to carry out a method of determining a breakpoint position in an ordered sequence of quantized transform coefficients of a block of image data for a hybrid variable length coding the ordered sequence. The breakpoint location in the sequence is between a low-frequency region and a high-frequency region. The hybrid variable length coding method includes 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 position in the sequence of the breakpoint. The breakpoint location is determining uses a relatively simple and fast method based on pre-defined cost criteria. A method is included that instead of coding the breakpoint separately, codes the breakpoint jointly with coefficient events.

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.