Techniques for high efficiency entropy coding of video data

A coder, comprising:

• a transformer, having an input for pixel blocks representing content of a source image and an output for respective blocks of transform coefficients;
• a quantizer, having an input for the blocks of transform coefficients and an output for respective quantized coefficients of the blocks of transform coefficients;
• an entropy coder, having an input for the quantized coefficients, that alternates between nonzero value coding and zero value coding of values of the quantized coefficients encountered along a scan direction among the pixel blocks, in which:
• during the nonzero value coding, the entropy coder outputs a first data item identifying a number of consecutive nonzero values followed by a data item for each of the nonzero values so identified, and
• during the zero value coding, the entropy coder outputs another data item identifying a number of consecutive zero values.

A non-transitory computer readable medium having stored thereon coded video data generated according to a coding method, comprising:

• transforming pixel blocks representing content of a source image into respective blocks of transform coefficients;
• quantizing the transform coefficients of each pixel block;
• entropy coding the quantized coefficients of the pixel blocks by, iteratively:
• transmitting a data item identifying a number of consecutive nonzero values encountered along a scan direction among the pixel blocks followed by other data items each representing a value of each of the identified number of consecutive nonzero values, and
• transmitting a data item identifying a number of consecutive zero values encountered along the scan direction.

A coding method consisting essentially of:

• transforming pixel blocks representing content of a source image into respective blocks of transform coefficients;
• quantizing the transform coefficients of each pixel block;
• entropy coding the quantized coefficients of the pixel blocks by,
• iteratively:
• a. transmitting data identifying a number of consecutive nonzero values encountered along a scan direction among the pixel blocks followed by a value of for each of the identified number of consecutive nonzero values, and
• b. transmitting data identifying a number of consecutive zero values encountered along the scan direction.