Systems and methods for adaptive extrapolation filter based intra prediction mode
An example method of video coding includes receiving a video bitstream for a plurality of blocks. When an extrapolation filter-based intra prediction (EIP) mode is active for a current block of the plurality of blocks, the method also includes determining, when a boundary condition is met for the current block, one or more EIP mode parameters from a first set of EIP parameters. When the boundary condition is not met for the current block, the method also includes determining the one or more EIP mode parameters from a second set of EIP parameters, where the second set of EIP parameters includes one or more parameters not included in the first set of EIP parameters. The method further includes reconstructing the current block using the one or more EIP mode parameters.
1 . A method of video decoding performed at a computing system having memory and one or more processors, the method comprising:
receiving a video bitstream comprising a plurality of blocks; and
when an extrapolation filter-based intra prediction (EIP) mode is active for a current block of the plurality of blocks:
when a boundary condition is met for the current block, determining one or more EIP mode parameters from a first set of EIP parameters, the boundary condition corresponding to at least one of:
a first number of available top rows of reconstruction samples being less than a first threshold, or
a second number of available left columns of reconstruction samples being less than a second threshold;
when the boundary condition is not met for the current block, determining the one or more EIP mode parameters from a second set of EIP parameters, wherein the second set of EIP parameters includes one or more parameters not included in the first set of EIP parameters; and
reconstructing the current block using the one or more EIP mode parameters.
2 . The method of claim 1 , wherein the one or more EIP mode parameters comprise a parameter for a reconstruction area for the EIP mode.
3 . The method of claim 1 , wherein the one or more EIP mode parameters comprise a parameter for a filter shape for the EIP mode.
4 . The method of claim 1 , further comprising:
parsing, from the video bitstream, an indicator indicating whether the current block of the plurality of blocks is to be decoded using EIP mode.
5 . The method of claim 1 , wherein the boundary condition involves a picture boundary, a subpicture boundary, a slice boundary, and/or a tile boundary.
6 . The method of claim 1 , wherein the boundary condition corresponds to the current block being located at a top partition boundary.
7 . The method of claim 1 , wherein the boundary condition corresponds to the current block being located at a left partition boundary.
8 . The method of claim 1 , further comprising, when the current block is located at a partition boundary, determining that the EIP mode is inactive for the current block.
9 . The method of claim 8 , wherein the partition boundary is a top-left partition boundary.
10 . The method of claim 1 , further comprising, when the EIP mode is active for the current block and when one or more samples in a reconstruction area for the EIP mode are unavailable, padding the one or more samples for the EIP mode.
11 . The method of claim 10 , wherein padding the one or more samples comprises using a predefined constant value to pad the one or more samples.
12 . The method of claim 11 , wherein the predefined constant value is based on a sample bit depth.
13 . The method of claim 10 , wherein padding the one or more samples comprises extending available sample values to pad the one or more samples.
14 . The method of claim 1 , wherein
the first set of EIP parameters includes a first set of reconstruction area types and filter shapes for the EIP mode,
the second set of EIP parameters includes a second set of reconstruction area types and filter shapes for the EIP mode, and
the first set of reconstruction area types and filter shapes for the EIP mode includes a subset of the second set of reconstruction area types and filter shapes for the EIP mode.
15 . A computing system, comprising:
control circuitry;
memory; and
one or more sets of instructions stored in the memory and configured for execution by the control circuitry, the one or more sets of instructions causing the control circuitry to perform:
receiving video data that includes a plurality of video blocks; and
when an extrapolation filter-based intra prediction (EIP) mode is active for a current block of the plurality of video blocks:
when a boundary condition is met for the current block, determining one or more EIP mode parameters from a first set of EIP parameters, the boundary condition corresponding to at least one of:
a first number of available top rows of reconstruction samples being less than a first threshold, or
a second number of available left columns of reconstruction samples being less than a second threshold;
when the boundary condition is not met for the current block, determining the one or more EIP mode parameters from a second set of EIP parameters, wherein the second set of EIP parameters includes one or more parameters not included in the first set of EIP parameters; and
encoding the current block using the one or more EIP mode parameters.
16 . The computing system of claim 15 , wherein the one or more sets of instructions further cause the control circuitry to perform:
signaling, via a video bitstream, an indicator indicating whether the current block of the plurality of video blocks is to be decoded using the EIP mode.
17 . A non-transitory computer-readable storage medium storing one or more sets of instructions which when executed by processing circuitry cause the processing circuitry to perform a method of encoding a bitstream, the method comprising:
receiving video data that includes a plurality of video blocks; and
when an extrapolation filter-based intra prediction (EIP) mode is active for a current block of the plurality of video blocks:
when a boundary condition is met for the current block, determining one or more EIP mode parameters from a first set of EIP parameters, the boundary condition corresponding to at least one of:
a first number of available top rows of reconstruction samples being less than a first threshold, or
a second number of available left columns of reconstruction samples being less than a second threshold;
when the boundary condition is not met for the current block, determining the one or more EIP mode parameters from a second set of EIP parameters, wherein the second set of EIP parameters includes one or more parameters not included in the first set of EIP parameters;
encoding, in the bitstream, the current block using the one or more EIP mode parameters; and
transmitting the bitstream.
18 . The computing system of claim 15 , wherein
the first set of EIP parameters includes a first set of reconstruction area types and filter shapes for the EIP mode,
the second set of EIP parameters includes a second set of reconstruction area types and filter shapes for the EIP mode, and
the first set of reconstruction area types and filter shapes for the EIP mode includes a subset of the second set of reconstruction area types and filter shapes for the EIP mode.
19 . The non-transitory computer-readable storage medium of claim 17 , wherein the bitstream comprises:
an indicator indicating whether the current block of the plurality of blocks is to be decoded using the EIP mode.
20 . The non-transitory computer-readable storage medium of claim 17 , wherein
the first set of EIP parameters includes a first set of reconstruction area types and filter shapes for the EIP mode,
the second set of EIP parameters includes a second set of reconstruction area types and filter shapes for the EIP mode, and
the first set of reconstruction area types and filter shapes for the EIP mode includes a subset of the second set of reconstruction area types and filter shapes for the EIP mode.