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 some embodiments, an electronic device for compressing video image data includes a housing, an image sensor, a memory device, and one or more processors. The image sensor can generate image data from light incident on the image sensor. The one or more processors can transform the image data to obtain transform coefficients, quantize the transform coefficients, encode the quantized transform coefficients, and store the quantized transform coefficients to the memory device. The one or more processors can encode the quantized transform coefficients at least by determining a range of multiple ranges in which one transform coefficient is included, determining a value within the range to which the one transform coefficient corresponds, encoding using a first algorithm the range as a range code, and encoding using a second algorithm the value as a value code.

In some embodiments, an electronic device for compressing video image data includes a housing, an image sensor, a memory device, and one or more processors. The image sensor can generate image data from light incident on the image sensor. The one or more processors can transform the image data to obtain transform coefficients, quantize the transform coefficients, encode the quantized transform coefficients, and store the quantized transform coefficients to the memory device. The one or more processors can encode the quantized transform coefficients at least by determining a range of multiple ranges in which one transform coefficient is included, determining a value within the range to which the one transform coefficient corresponds, encoding using a first algorithm the range as a range code, and encoding using a second algorithm the value as a value code.

A method of video encoding includes determining whether a plurality of constraint flags of a constraint information group are to be signaled for a subset of coding blocks, and signaling a gate flag indicating whether the plurality of constraint flags of the constraint information group are signaled. The gate flag is signaled in constraint information in a syntax structure of a coded video bitstream. In accordance with the signaled gate flag indicating that the plurality of constraint flags of the constraint information group are signaled, the method further includes signaling the plurality of constraint flags of the constraint information group in the constraint information in the syntax structure of the coded video bitstream. In accordance with the plurality of constraint flags being signaled in the constraint information, the method further includes encoding the subset of coding blocks based on the plurality of constraint flags.

A method of video encoding includes determining whether a plurality of constraint flags of a constraint information group are to be signaled for a subset of coding blocks, and signaling a gate flag indicating whether the plurality of constraint flags of the constraint information group are signaled. The gate flag is signaled in constraint information in a syntax structure of a coded video bitstream. In accordance with the signaled gate flag indicating that the plurality of constraint flags of the constraint information group are signaled, the method further includes signaling the plurality of constraint flags of the constraint information group in the constraint information in the syntax structure of the coded video bitstream. In accordance with the plurality of constraint flags being signaled in the constraint information, the method further includes encoding the subset of coding blocks based on the plurality of constraint flags.

An embodiment of the present description provides a decoding method and device for a quantization block as well as an electronic device. The method comprises: determining the scanning order of quantization coefficients in the quantization block, initializing the scanning position of the quantization coefficients, and decoding a run-length; adding a subscript value of the current scanning position and the value of the run-length to obtain the scanning position of nonzero coefficients, decoding the values of the nonzero coefficients; judging whether the subscript value of the nonzero coefficients is the maximum subscript value, if yes, ending the decoding of the quantization block; if not, judging whether there are undecoded nonzero coefficients, and if there are no undecoded nonzero coefficients, ending the decoding of the quantization block; if there are undecoded nonzero coefficients, adding 1 to the subscript value of the decoded nonzero coefficients to obtain an updated current scanning position, taking the current scanning position as the initial scanning position to decode the next run-length until the decoding of the quantization block is completed. The technical solution of the present application can improve the decoding efficiency of quantization block.

Measures are provided to encode a signal. An input frame is received and down-sampled to obtain a down-sampled frame. The down-sampled frame is passed to an encoding module which encodes the down-sampled frame to generate an encoded frame. A decoded frame is obtained from a decoding module which generates the decoded frame by decoding the encoded frame. A set of residual data is generated by taking a difference between the decoded frame and the down-sampled frame and is encoded to generate a set of encoded residual data. The encoding comprises transforming the set of residual data into a transformed set of residual data. The set of encoded residual data is output to a decoder to enable the decoder to reconstruct the input frame. Measures are also provided to decode a signal.

Measures are provided to encode a signal. An input frame is received and down-sampled to obtain a down-sampled frame. The down-sampled frame is passed to an encoding module which encodes the down-sampled frame to generate an encoded frame. A decoded frame is obtained from a decoding module which generates the decoded frame by decoding the encoded frame. A set of residual data is generated by taking a difference between the decoded frame and the down-sampled frame and is encoded to generate a set of encoded residual data. The encoding comprises transforming the set of residual data into a transformed set of residual data. The set of encoded residual data is output to a decoder to enable the decoder to reconstruct the input frame. Measures are also provided to decode a signal.

A system includes a first encoder configured to receive first input bits and generate a first stream of first bits based on the first input bits, a bit generator configured to receive second inputs bits and generate a second stream of second bits based on the second input bits, and a PAM4 transmitter configured to receive the first stream of first bits and the second stream of second bits, and generate PAM4 symbols based at least on the first stream of first bits.

Sketch copy mode may be used to code blocks comprising irregular lines, syntax redundancy may be removed from blocks with special characteristics, and/or run value coding may be simplified. The parsing dependencies in palette coding design may be removed. For example, the context modeling dependency of the syntax element palette_transpose_flag be removed, for example, by simplifying the corresponding context model. The context modeling of the syntax element palette mode may be removed, for example, by using run-length coding without using context. The syntax parsing dependencies and/or the syntax signaling dependencies that are related with escape color signaling may be removed. A palette table generation process may handle input screen content video with high bit depths, for example, at the encoder side.