Method and apparatus for decoding a video signal
The present invention relates to a method for decoding a video signal, comprising: obtaining adaptive transform size flag information for a 1st coding unit, the adaptive transform size flag information indicating whether a coding unit is partitioned in to coding units each of which has a half size in horizontal and vertical directions; obtaining adaptive transform size flag information for each 2nd coding unit, if the adaptive transform size flag information of a 1st coding unit is true, the 2nd coding unit indicating a sub-block included in the 1st coding unit; determining a size of a transform unit based on the adaptive transform size flag information; wherein the adaptive transform size flag information is obtained based on a size of a current transform unit, a minimum transform size, and a maximum transform size.
1. A method for decoding a bitstream for a video signal, the method comprising:
obtaining, from the bitstream and based on a predefined condition being satisfied, split indication information for a transform block, the split indication information indicating whether the transform block is split into four transform sub-blocks that each have a half horizontal size and a half vertical size of the transform block;
based on the split indication information for the transform block having a first value, partitioning the transform block into the four transform sub-blocks; and
based on the split indication information for the transform block having a second value, performing a transform operation on the transform block to obtain pixel values of the transform block,
wherein the predefined condition includes:
a current size of the transform block being less than or equal to a maximum transform size, and
the current size of the transform block being greater than a minimum transform size, and
wherein, based on the split indication information having the first value, for each of the four transform sub-blocks into which the transform block was partitioned, repeating the steps of:
obtaining split indication information for the transform sub-block;
based on the split indication information for the transform sub-block having the first value, partitioning the transform sub-block into the four transform sub-sub-blocks; and
based on the split indication information for the transform sub-block having the second value, performing a transform operation on the transform sub-block to obtain pixel values of the transform sub-block.
2. The method according to claim 1 , wherein the maximum transform size is 32×32 and the minimum transform size is 4 x4.
3. The method according to claim 1 , wherein performing the transform operation includes obtaining transform coefficient information from the bitstream, and performing the transform operation on the obtained transform coefficient information.
4. The method according to claim 1 , further comprising:
obtaining coded block flag information for the transform block from the bitstream based on the split indication information having the second value, the coded block flag information indicating whether the transform block includes one or more transform coefficient information not equal to 0.
5. The method according to claim 1 , wherein, based on the current size of the transform block being less than or equal to the minimum transform size, the split indication information is derived to have the second value.
6. An apparatus for decoding a bitstream for a video signal, the apparatus comprising:
a transform size determining unit configured to obtain split indication information for a transform block from the bitstream based on a predefined condition being satisfied, the split indication information indicating whether the transform block is split into four transform sub-blocks, each transform sub-block having a half horizontal size and a half vertical size of the transform block, and to partition the transform block into the four transform sub-blocks based on the split indication information for the transform block having a first value; and
a transform decoding unit configured to, based on the split indication information for the transform block having a second value, perform a transform operation on the transform block to obtain pixel values of the transform block,
wherein the predefined condition includes:
a current size of the transform block being less than or equal to a maximum transform size, and
the current size of the transform block being greater than a minimum transform size, and
wherein the transform size determining unit is further configured to obtain split indication information for each of the four transform sub-blocks, and, based on the split indication information for each of the four transform sub-blocks having the first value, to partition each of the four transform sub-blocks into four transform sub-sub-blocks, and
wherein the transform decoding unit is further configured to, based on the split indication information for the transform block having the second value, perform the transform operation on the each of the four transform sub-blocks to obtain pixel values of each of the four transform sub-blocks.
7. The apparatus according to claim 6 , wherein the maximum transform size is 32×32 and the minimum transform size is 4 x4.
8. The apparatus according to claim 6 , wherein the transform decoding unit is further configured to perform the transform operation by obtaining transform coefficient information from the bitstream, and performing the transform operation on the obtained transform coefficient information.
9. The apparatus according to claim 6 , wherein the transform decoding unit is further configured to obtain coded block flag information for the transform block from the bitstream based on the split indication information having the second value, the coded block flag information indicating whether the transform block includes one or more transform coefficient information not equal to 0.
10. The apparatus according to claim 6 , wherein based on the current size of the transform block being less than or equal to the minimum transform size, the split indication information is derived to have the second value.