System, method and computer-readable medium for encoding a signal into macroblocks

A decoder that decodes received macroblocks in a bitstream, a respective macroblock comprising up to four luminance blocks, the decoder comprising:na first module controlling a processor to determine a quantization parameter from quantization data in the bitstream;a second module controlling the processor to generate a luminance scalar according to a first piece-wise linear transformation of the quantization parameter, wherein:n(i) the luminance scalar equals 8 whenever the quantization parameter falls within the values 1 through 4, inclusive;(ii) the luminance scalar equals 2 times the quantization parameter whenever the quantization parameter falls within the values 5 through 8, inclusive;(iii) the luminance scalar equals the quantization parameter plus 8 whenever the quantization parameter falls within the values 9 through 24, inclusive; and(iv) the luminance scalar equals 2 times the quantization parameter;a third module controlling the processor to inverse quantize a DC coefficient of a respective luminance block of the up to four luminance blocks by the luminance scalar to yield a respective inverse quantized DC coefficient;a fourth module controlling the processor to transform data of the up to four luminance blocks, including the respective inverse quantized DC coefficient, according to an inverse discrete cosine transform; anda fifth module controlling the processor to merge data of the up to four luminance blocks to generate image data associated with the respective macroblock.

A decoder that decodes a signal from a bitstream that comprises macroblocks and quantization data, each macroblock comprising up to two chrominance blocks, the decoder comprising:na first module controlling a processor to determine a quantization parameter from the quantization data in the bitstream;a second module controlling the processor to generate a chrominance scalar according to a first piece-wise linear transformation of the quantization parameter as follows:na) the chrominance scalar equals 8 whenever the quantization parameter falls within the values 1 through 4, inclusive;(b) the chrominance scalar equals (the quantization parameter+13)/2 whenever the quantization parameter falls within the values 5 through 24, inclusive; and(c) the chrominance scalar equals the quantization parameter minus 6 whenever the quantization parameter falls within the values 25 through 31, inclusive;a third module controlling the processor to inverse quantize a DC coefficient of a respective chrominance block of the two chrominance blocks by the chrominance scalar to yield a respective inverse quantized chrominance DC coefficient;a fourth module controlling the processor to transform data of the up to two chrominance blocks, including the respective inverse quantized chrominance DC coefficient, according to an inverse discrete cosine transform; anda fifth module controlling the processor to merge data of up to two chrominance blocks to generate image data associated with the macroblock.

A method of decoding a signal having macroblocks, each macroblock comprising up to four luminance blocks, the method comprising:n(1) receiving macroblocks and quantization data in a bitstream;(2) determining a quantization parameter from the quantization data in the bitstream;(3) generating a luminance scalar according to a first piece-wise linear transformation of the quantization parameter as follows:n(i) the luminance scalar equals 8 whenever the quantization parameter falls within the values 1 through 4, inclusive;(ii) the luminance scalar equals 2 times the quantization parameter whenever the quantization parameter falls within the values 5 through 8, inclusive;(iii) the luminance scalar equals the quantization parameter plus 8 whenever the quantization parameter falls within the values 9 through 24, inclusive; and(iv) the luminance scalar equals 2 times the quantization parameter;(4) inverse quantizing by the luminance scalar a DC coefficient of a respective luminance block of the up to four luminance blocks to yield a respective inverse quantized DC coefficient;(5) transforming data of the blocks, including the respective inverse quantized DC coefficient, according to an inverse discrete cosine transform; and(6) merging data of the up to four luminance blocks to generate image data associated with the macroblock.

A method of decoding a signal into macroblocks, each macroblock comprising up to two chrominance blocks, the method comprising:n(1) receiving macroblocks and quantization data from a bitstream;(2) determining a quantization parameter from the quantization data in the bitstream;(3) generating a chrominance scalar according to a first piece-wise linear transformation of the quantization parameter as follows:n(i) the chrominance scalar equals 8 whenever the quantization parameter falls within the values 1 through 4, inclusive;(ii) the chrominance scalar equals (the quantization parameter+13)/2 whenever the quantization parameter falls within the values 5 through 24, inclusive; and(iii) the chrominance scalar equals the quantization parameter minus 6 whenever the quantization parameter falls within the values 25 through 31, inclusive;(4) inverse quantizing a DC coefficient of a respective chrominance block of the up to two chrominance blocks by the chrominance scalar to yield a respective inverse quantized DC coefficient;(5) transforming data of the up to two chrominance blocks, including the respective inverse quantized DC coefficient, according to an inverse discrete cosine transform; and(6) merging data of the up to two chrominance blocks to generate image data associated with a respective macroblock.