Context adaptive position and amplitude coding of coefficients for video

摘要

A coding method, apparatus, and medium with software encoded thereon to implement a coding method. The coding method includes encoding the position of non-zero-valued coefficients in an ordered series of quantized transform coefficients of a block of image data, including encoding events using variable length coding using a plurality of variable length code mappings that each maps events to codewords, the position encoding including switching between the code mappings based on the context. The coding method further includes encoding amplitudes of the non-zero-valued coefficients using variable dimensional amplitude coding in the reverse order of the original ordering of the series.

主权项

1. A method of coding using a coding apparatus, the method comprising:
obtaining an ordered series coefficients associated with a block of image data, the coefficients including a first set of amplitudes and a second set of amplitudes; position encoding at least some of the coefficients having amplitudes different from the first set of amplitudes, the position encoding including forming position codewords using a plurality of position code mappings that map position events to position codewords; encoding amplitudes of the coefficients that are different from the first set of amplitudes by encoding amplitude events using more than one amplitude code mapping, the encoding of amplitudes being in the reverse order of the original ordering of the series and forming amplitude codewords, wherein amplitude code mapping is at least in part dependent on whether or not the amplitude event includes a coefficient having other than a most likely-to-occur amplitude that is adjacent to at least one coefficient having a most likely-to-occur amplitude; and concatenating the position and amplitude codewords.