The invention relates to a method and apparatus for image compression, particularly to an improved block-coding apparatus and method for image compression. Image compression systems such as JPEG and JPEG2000 are known and popular standards for image compression. Many of the advantageous features of JPEG2000 derive from the use of the EBCOT algorithm (Embedded Block-Coding with Optimized Truncation). One drawback of the JPEG2000 standards is computational complexity. This application discloses a relatively fast block-coding algorithm, particularly as compared with the standard JPEG2000 EBCOT algorithm. Computational complexity is reduced.

The invention relates to a method and apparatus for image compression, particularly to an improved block-coding apparatus and method for image compression. Image compression systems such as JPEG and JPEG2000 are known and popular standards for image compression. Many of the advantageous features of JPEG2000 derive from the use of the EBCOT algorithm (Embedded Block-Coding with Optimized Truncation). One drawback of the JPEG2000 standards is computational complexity. This application discloses a relatively fast block-coding algorithm, particularly as compared with the standard JPEG2000 EBCOT algorithm. Computational complexity is reduced.

In one aspect, a method of fast data compression operates on input data comprising plural J-bit bytes (e.g., 16-bit bytes). The method computes a first difference value between one pair of the input J-bit bytes, and determines that this first difference value can be represented by K bits, where K<J. The method further computes a second difference value between a second pair of the input J-bit bytes, and determines that this second difference value can be represented by M bits, where M<K. These K- and M-bit difference values are included in a composite output data string that also includes four data tags. One tag indicates the first difference value is represented by K bits. Another indicates the second difference value is represented by M bits. The final two tags indicate the polarities of the first and second difference values. A great variety of other features and arrangements are also detailed.

A method for decoding an encoded video bit stream in a video decoder is provided that includes determining a scan pattern type for a transform block to be decoded, decoding a column position X and a row position Y of a last non-zero coefficient in the transform block from the encoded video bit stream, selecting a column-row inverse transform order when the scan pattern type is a first type, selecting a row-column inverse transform order when the scan pattern type is a second type, and performing one dimensional (1D) inverse discrete cosine transformation (IDCT) computations according to the selected transform order to inversely transform the transform block to generate a residual block.

A method for decoding an encoded video bit stream in a video decoder is provided that includes determining a scan pattern type for a transform block to be decoded, decoding a column position X and a row position Y of a last non-zero coefficient in the transform block from the encoded video bit stream, selecting a column-row inverse transform order when the scan pattern type is a first type, selecting a row-column inverse transform order when the scan pattern type is a second type, and performing one dimensional (1D) inverse discrete cosine transformation (IDCT) computations according to the selected transform order to inversely transform the transform block to generate a residual block.

A method and apparatus for decoding JVET video, including receiving a bitstream, and parsing said bitstream to identify a syntax element indicating an intra direction mode to use for generating at least one predictor. The intra direction mode is a first intra direction mode in a plurality of intra direction modes that includes at least one weighted intra direction mode that corresponds to a non-weighted intra direction mode. The syntax element may identify whether to use a non-weighted or weighted intra direction mode to generate the at least one predictor. Thus, the coding unit may be coded in accordance with the at least one generated predictor associated with the selected intra direction mode.

A method and apparatus for decoding JVET video, including receiving a bitstream, and parsing said bitstream to identify a syntax element indicating an intra direction mode to use for generating at least one predictor. The intra direction mode is a first intra direction mode in a plurality of intra direction modes that includes at least one weighted intra direction mode that corresponds to a non-weighted intra direction mode. The syntax element may identify whether to use a non-weighted or weighted intra direction mode to generate the at least one predictor. Thus, the coding unit may be coded in accordance with the at least one generated predictor associated with the selected intra direction mode.

Lossy or lossless compression and transmission, comprising the steps of: (i) receiving an input image; (ii) encoding it to produce a y latent representation; (iii) encoding the y latent representation to produce a z hyperlatent representation; (iv) quantizing the z hyperlatent representation to produce a quantized z hyperlatent representation; (v) entropy encoding the quantized z hyperlatent representation into a first bitstream, (vi) processing the quantized z hyperlatent representation to obtain a location entropy parameter μ.sub.y, an entropy scale parameter σy, and a context matrix A.sub.y of the y latent representation; (vii) processing the y latent representation, the location entropy parameter μ.sub.y and the context matrix A.sub.y, to obtain quantized latent residuals; (viii) entropy encoding the quantized latent residuals into a second bitstream; and (ix) transmitting the bitstreams.

Lossy or lossless compression and transmission, comprising the steps of: (i) receiving an input image; (ii) encoding it to produce a y latent representation; (iii) encoding the y latent representation to produce a z hyperlatent representation; (iv) quantizing the z hyperlatent representation to produce a quantized z hyperlatent representation; (v) entropy encoding the quantized z hyperlatent representation into a first bitstream, (vi) processing the quantized z hyperlatent representation to obtain a location entropy parameter μ.sub.y, an entropy scale parameter σy, and a context matrix A.sub.y of the y latent representation; (vii) processing the y latent representation, the location entropy parameter μ.sub.y and the context matrix A.sub.y, to obtain quantized latent residuals; (viii) entropy encoding the quantized latent residuals into a second bitstream; and (ix) transmitting the bitstreams.

A video encoder comprises an application-specific integrated circuit (ASIC) video encoding unit configured to receive via an interface in a processing order, quantized transform coefficients for a transform unit of a frame of a video being encoded. The ASIC unit is configured to analyze at least a portion of the quantized transform coefficients in the processing order to identify one or more end-of-block candidate positions in the processing order. The ASIC unit is configured to translate the one or more end-of-block candidate positions for the at least a portion of the quantized transform coefficients to one or more scan order versions of the one or more end-of-block candidate positions. The ASIC unit is configured to determine a true end-of-block position for the quantized transform coefficients using the one or more scan order versions of the one or more end-of-block candidate positions.