An image coding method includes: generating a predicted block; calculating a residual block; calculating quantized coefficients by performing transform and quantization on the residual block; calculating a coded residual block by performing inverse quantization and inverse transform on the quantized coefficients; generating a temporary coded block; determining whether or not an offset process is required, to generate first flag information indicating a result of the determination; executing the offset process on the temporary coded block when it is determined that the offset process is required; and performing variable-length coding on the quantized coefficients and the first flag information.

An image coding method includes: generating a predicted block; calculating a residual block; calculating quantized coefficients by performing transform and quantization on the residual block; calculating a coded residual block by performing inverse quantization and inverse transform on the quantized coefficients; generating a temporary coded block; determining whether or not an offset process is required, to generate first flag information indicating a result of the determination; executing the offset process on the temporary coded block when it is determined that the offset process is required; and performing variable-length coding on the quantized coefficients and the first flag information.

An encoder includes a plurality of registers and is configured to: sequentially receive an array of coefficients, each of the coefficients being decomposed into a plurality of bits located at a plurality of corresponding bit positions of the coefficient; and concurrently operate on the plurality of bits of each of the coefficients.

An encoder includes a plurality of registers and is configured to: sequentially receive an array of coefficients, each of the coefficients being decomposed into a plurality of bits located at a plurality of corresponding bit positions of the coefficient; and concurrently operate on the plurality of bits of each of the coefficients.

An apparatus for image coding includes a processor to: execute a determining process that includes, when a specific entry included in a first palette for use in coding a first block in a coding-target image is not an entry candidate for a second palette for use in coding a second block to be coded after the first block, determining an entry to be included in the second palette based on a first index indicating a code amount to be generated when the specific entry is to be included in the second palette and a second index indicating a code amount to be generated when the specific entry is not to be included in the second palette; execute a generating process that includes generating the second palette including the entry determined in the determining process; and execute a palette coding process that includes coding the second block by the second palette.

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.

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.

This application discloses an image encoding method and apparatus, an image decoding method and apparatus, and a chip. In the encoding method, first, a run-length value sequence and a level value sequence are obtained by using a quantized sequence of an image; updated distribution probabilities of level values are obtained based on distribution probabilities of run-length values and the level values and according to a mapping rule; finally, entropy encoding is performed based on the level value sequence and the updated distribution probabilities of the level values, to output encoded image data. A decoder side only needs to additionally learn of the mapping rule to complete decoding. The method is simple to implement, and can improve image compression efficiency and effectively reduce an amount of data for representing the image.

This application discloses an image encoding method and apparatus, an image decoding method and apparatus, and a chip. In the encoding method, first, a run-length value sequence and a level value sequence are obtained by using a quantized sequence of an image; updated distribution probabilities of level values are obtained based on distribution probabilities of run-length values and the level values and according to a mapping rule; finally, entropy encoding is performed based on the level value sequence and the updated distribution probabilities of the level values, to output encoded image data. A decoder side only needs to additionally learn of the mapping rule to complete decoding. The method is simple to implement, and can improve image compression efficiency and effectively reduce an amount of data for representing the image.