Abstract: This disclosure provides methods, devices, and systems for image compression. The present implementations more specifically relate to image compression techniques that support inter-channel encoding of codewords. An encoder implementing an image compression operation may apply a spatial-frequency transform to a number (N) arrays of pixel values associated with N color channels, respectively, and may quantize the result to produce N arrays of quantized coefficients. In some aspects, the encoder may map each quantized coefficient of the N arrays of quantized coefficients to a data structure and may encode the data structure as one or more codewords associated with a lossless compression scheme. In some implementations, the mapping may arrange the quantized coefficients in the data structure in order of decreasing (or increasing) amplitude, independent of color channel.

Abstract: 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.