Adaptive resolution management prediction rescaling
A method includes receiving a reference frame, determining, for a current block, a scaling constant, determining a scaled reference block using the reference frame and the scaling constant, determining a scaled prediction block using the scaled reference block, and reconstructing pixel data of the current block and using the rescaled prediction block. Related apparatus, systems, techniques and articles are also described.
1. A decoder configured to:
receive a bitstream comprising a reference picture, a current picture having a resolution different from the reference picture and including a first block and a second block, and information useful for determining a scaling constant;
determine a scaling constant using the information in the bitstream;
determine a scaled prediction block from the reference picture by:
determining a location of the scaled prediction block by scaling a motion vector component using the scaling constant;
scaling the resolution of a block of the reference picture using the scaling constant and applying a filter determined specifically for the prediction block and not determined for the whole reference picture;
reconstruct the first block using the scaled prediction block; and
reconstruct the second block without using a scaled prediction block.
2. The decoder of claim 1 wherein, the information in the bitstream useful for determining a scaling constant includes an index to a set of predetermined values and said index is utilized to determine the scaling constant.
3. A decoder configured to:
receive a bit stream including a current coded picture comprising a first plurality of coded blocks and a second plurality of coded blocks;
decode each block of the first plurality of coded blocks by:
determining a scaling constant using information in the bitstream;
determining a scaled prediction block from a reference picture having a different resolution than the current coded picture, by scaling a motion vector component to determine the location of the scaled prediction block, scaling a block from the reference picture using the scaling constant, and applying a filter determined individually for the prediction block;
decoding each block of the first plurality of coded blocks using its scaled prediction block; and
decode each block of the second plurality of coded blocks without using a scaled prediction block of a reference picture and without applying a resolution changing filter specifically determined for a block of a reference picture.
4. The decoder of claim 3 wherein, the information in the bitstream includes an index to a set of predetermined values and said index is utilized to determine the scaling constant.