CPC H04N 19/119 (2014.11) [H04N 19/124 (2014.11); H04N 19/129 (2014.11); H04N 19/182 (2014.11); H04N 19/436 (2014.11); H04N 19/625 (2014.11); H04N 19/63 (2014.11); H04N 19/70 (2014.11); H04N 19/91 (2014.11)] | 5 Claims |
1. A video decoding method for decoding frequency coefficients of a two dimensional frequency conversion unit having 8×8, 8×16, 16×8 or 16×16 pixel size, the frequency conversion unit being a unit of transforming residual signals that are differences between original pixel values and predicted pixel values, the method comprising:
reconstructing the frequency coefficients of the two dimensional frequency conversion unit by decoding a bitstream, thereby generating a frequency conversion block having a size of the two dimensional frequency conversion unit, wherein the frequency coefficients is values generated by transform of the residual signals from a spatial domain into a frequency domain; and
inversely transforming the frequency conversion block from the frequency domain to the spatial domain, by using a transform size identical to the size of the two dimensional frequency conversion unit,
wherein the frequency conversion block is generated by reconstructing and inversely scanning the frequency coefficients of the two dimensional frequency conversion unit in the unit of two dimensional subblocks divided from the two dimensional frequency conversion unit, all of the subblocks in the two dimensional frequency conversion unit having a 4×4 pixel size irrespective of whether the two dimensional frequency conversion unit is of 8×8, 8×16, 16×8 or 16×16 pixel size,
wherein the reconstructing and inversely scanning of the frequency coefficients in the unit of the subblocks comprises:
decoding, from the bitstream, subblock encoding information indicating whether a subblock of the 4×4 pixel size corresponding thereto has at least one non-zero frequency coefficient, wherein,
a value of the decoded subblock encoding information is 0 when the subblock does not have at least one non-zero frequency coefficient, and
the value of the decoded subblock encoding information is 1 when the subblock has at least one non-zero frequency coefficient,
reconstructing from the bitstream and inversely scanning frequency coefficients corresponding to the subblock, when the decoded subblock encoding information has a value of 1, and
setting all frequency coefficients corresponding to the subblock to 0, when the decoded subblock encoding information has a value of 0,
wherein each of the subblocks includes frequency coefficients corresponding to a frequency range, the frequency range of each of the subblocks being different from those of another subblocks,
wherein the frequency coefficients which are located at different positions in each of the subblocks are values in the frequency domain which correspond to different frequencies.
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