A method for processing a video signal according to the present invention comprises: determining a length of a current string, which is decoded on the basis of a sample string matching technique in a current block; determining a reference string on the basis of at least one between the length of the current string and a string vector for the current string; and predicting the current string using the reference string.

A method for processing a video signal according to the present invention comprises: determining a length of a current string, which is decoded on the basis of a sample string matching technique in a current block; determining a reference string on the basis of at least one between the length of the current string and a string vector for the current string; and predicting the current string using the reference string.

An encoder (300) configured to receive an input video (302) comprising respective frames, each frame being divided into a plurality of tiles and each tile being divided into a plurality of blocks. The encoder is configured to generate a base encoded stream (310) using abase encoder (306), determine (334) a temporal mode for one or more further encoded enhancement streams (328) generated using an enhancement encoder and generate the one or more further encoded enhancement streams (328) according to the determined temporal mode. The temporal mode is either a first temporal mode that does not apply non-zero values from a temporal buffer or a second temporal mode that does apply non-zero values from the temporal buffer (332). Generating the one or more further encoded enhancement streams comprises applying a transform (348) to each of a series of blocks. The temporal mode is determined for one or more of a frame, tile or block.

An encoder (300) configured to receive an input video (302) comprising respective frames, each frame being divided into a plurality of tiles and each tile being divided into a plurality of blocks. The encoder is configured to generate a base encoded stream (310) using abase encoder (306), determine (334) a temporal mode for one or more further encoded enhancement streams (328) generated using an enhancement encoder and generate the one or more further encoded enhancement streams (328) according to the determined temporal mode. The temporal mode is either a first temporal mode that does not apply non-zero values from a temporal buffer or a second temporal mode that does apply non-zero values from the temporal buffer (332). Generating the one or more further encoded enhancement streams comprises applying a transform (348) to each of a series of blocks. The temporal mode is determined for one or more of a frame, tile or block.

Methods incorporating extensions to copy-above mode for palette mode coding are disclosed. In one aspect, the method includes coding a current pixel of a current block of video data in copy-previous mode via coding a previous line index. The coding of the current pixel in copy-previous mode further including identifying a number of candidate values for the previous line index, identifying a number of escape pixels in a column of pixels above the current pixel in the current block, and reducing a number of candidate values of the previous line index by the number of identified escape pixels.

Methods incorporating extensions to copy-above mode for palette mode coding are disclosed. In one aspect, the method includes coding a current pixel of a current block of video data in copy-previous mode via coding a previous line index. The coding of the current pixel in copy-previous mode further including identifying a number of candidate values for the previous line index, identifying a number of escape pixels in a column of pixels above the current pixel in the current block, and reducing a number of candidate values of the previous line index by the number of identified escape pixels.

A video input interface receives input video data in a normal state. A control input interface receives character data for On Screen Display (OSD) in a setup state. An encoder encodes the character data and stores encoded compressed data in a memory in the setup state. A decoder receives an instruction signal designating the character data to be displayed, reads, and decodes one piece of compressed data corresponding to the instruction signal from the memory, and reproduces the original character data in the normal state. A multiplexer superimposes character data on frame data and outputs the data.

A video input interface receives input video data in a normal state. A control input interface receives character data for On Screen Display (OSD) in a setup state. An encoder encodes the character data and stores encoded compressed data in a memory in the setup state. A decoder receives an instruction signal designating the character data to be displayed, reads, and decodes one piece of compressed data corresponding to the instruction signal from the memory, and reproduces the original character data in the normal state. A multiplexer superimposes character data on frame data and outputs the data.

This disclosure provides methods, devices, and systems for data compression. The present implementations more specifically relate to lossless data compression techniques that combine entropy coding with run-length encoding of zeroes. In some aspects, an encoder may obtain a sequence of integer values representing a frame of data and may iteratively scan the sequence for runs of zeros. During each iteration of the scan, the encoder may increment a count value (N) if the current integer value is equal to zero or, if the current integer value is not equal to zero, output a pattern of bits representing the current count value or the current integer value. In some implementations, the pattern of bits may include a codeword associated with an entropy encoding scheme. More specifically, the encoder may encode the current integer value as the codeword if N>0 and may encode the current count value as the codeword if N=0.

Systems and methods are provided for encoding a multi-pixel caching scheme for lossless encoders. The systems and methods can include obtaining a sequence of pixels, determining repeating sub-sequences of the sequence of pixels consisting of a single repeated pixel and non-repeating sub-sequences of the sequence of pixels, responsive to the determination, encoding the repeating sub-sequences using a run-length of the repeated pixel and encoding the non-repeating sub-sequences using a multi-pixel cache, wherein the encoding using a multi-pixel cache comprises, encoding non-repeating sub-sequences stored in the multi-pixel cache as the location of the non-repeating sub-sequences in the multi-pixel cache, and encoding non-repeating sub-sequences not stored in the multi-pixel cache using the value of the pixels in the non-repeating sub-sequences.