Inter-layer prediction method for video signal
The present invention relates to a method for conducting interlayer texture prediction in encoding or decoding of video signal. The present method constructs a pair of frame macro blocks from a single field macro block or vertically-adjacent two field macro blocks of a base layer, and using texture information of the constructed pair of frame macro blocks in interlayer texture predication of a pair of frame macro blocks of a current layer.
1. A method for decoding an image signal comprising:
deriving, by a tangible decoding apparatus, virtual position information of a corresponding field macroblock pair, the corresponding field macroblock pair corresponding to a field macroblock pair of an enhanced layer;
deriving, by the tangible decoding apparatus, position information of a reference frame macroblock pair based on the virtual position information of the corresponding macroblock pair, the reference frame macroblock pair being in a base layer;
predicting, by the tangible decoding apparatus, motion information of the field macroblock pair of the enhanced layer from motion information of the reference frame macroblock pair according to the position information of the reference frame macroblock pair; and
decoding, by the tangible decoding apparatus, the field macroblock pair of the enhanced layer by using the motion information of the field macroblock pair of the enhanced layer,
wherein the motion information of the field macroblock pair and the reference frame macroblock pair includes a reference index and a motion vector, the field macroblock pair is two vertically adjacent field macroblocks, and the reference frame macroblock pair is two vertically adjacent frame macroblocks,
wherein the motion vector of the field macroblock pair is predicted as zero when the field macroblock pair is predicted based on an intra-coded macroblock.
2. The method of claim 1 , wherein the corresponding field macroblock pair is composed of a top field macroblock and a bottom field macroblock, an upper part of the top field macroblock being composed of even lines in a top macroblock of the reference frame macroblock pair, a lower part of the top field macroblock being composed of even lines in a bottom macroblock of the reference frame macroblock pair, an upper part of the bottom field macroblock being composed of odd lines in the top macroblock of the reference frame macroblock pair, and a lower part of the bottom field macroblock being composed of odd lines in a bottom macroblock of the reference frame macroblock pair.
3. The method of claim 1 ,
wherein the intra-coded macroblock is included in the reference frame macroblock pair, and the motion vector of the field macroblock pair is predicted by a unit of 4×4 block.
4. The method of claim 1 , wherein the field macroblock pair of the enhanced layer is included in a MacroBlock Adaptive Frame Field frame (MBAFF frame) of the enhanced layer, the MacroBlock Adaptive Frame Field frame (MBAFF frame) being a frame including macroblocks adaptively decoded as a frame macroblock or field macroblock.
5. A tangible decoding apparatus for decoding an image signal, comprising:
a decoding unit configured to,
derive virtual position information of a corresponding field macroblock pair,
derive position information of reference frame macroblock pair based on the virtual position information of the corresponding field macroblock pair,
predict motion information of an field macroblock pair of an enhanced layer from motion information of the reference frame macroblock pair according to the position information of the reference frame macroblock pair, and
decode the field macroblock pair of the enhanced layer by using the motion information of the field macroblock pair of the enhanced layer,
the corresponding field macroblock pair corresponding to the field macroblock pair of the enhanced layer, the reference frame macroblock pair being in a base layer, the motion information of the field macroblock pair and the reference frame macroblock pair includes a reference index and a motion vector, the field macroblock pair is two vertically adjacent field macroblocks, and the reference frame macroblock pair is two vertically adjacent frame macroblocks,
wherein the motion vector of the field macroblock pair is predicted as zero when the field macroblock pair is predicted based on an intra-coded macroblock.
6. The apparatus of claim 5 , wherein the corresponding field macroblock pair is composed of a top field macroblock and a bottom field macroblock, an upper part of the top field macroblock being composed of even lines in a top macroblock of the reference frame macroblock pair, a lower part of the top field macroblock being composed of even lines in a bottom macroblock of the reference frame macroblock pair, an upper part of the bottom field macroblock being composed of odd lines in the top macroblock of the reference frame macroblock pair, and a lower part of the bottom field macroblock being composed of odd lines in a bottom macroblock of the reference frame macroblock pair.
7. The apparatus of claim 5 ,
wherein the intra-coded macroblock is included in the reference frame macroblock pair, and the motion vector of the field macroblock pair is predicted by a unit of 4×4 block.
8. The apparatus of claim 5 , wherein the field macroblock pair of the enhanced layer is coded adaptively as a frame macroblock or field macroblock for each macroblock.