Modified coding for transform skipping
AssigneeVelos Media, LLC
InventorsDake He, Jing Wang, Gaëlle Christine Martin-Cocher
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Abstract
Methods and devices for modified coding of blocks of residuals in the case of transform skipping. To better align the data with assumptions upon which the entropy coding scheme is based, the block of residual data is permuted at the encoder prior to entropy coding. The block of reconstructed data is then inverse permuted at the decoder to recover the reconstructed block of residuals. The permutation may include 180 rotation of the block, which may be of particular benefit in the case of intra-coded residuals.
Claims25
A method of decoding a bitstream of encoded video in a video decoder to reconstruct residuals, the method comprising:
- determining that transform skipping is enabled for a block of residuals, meaning that no transform was applied during encoding and no inverse transform will be applied during decoding;
- reconstructing, based on a scan order, a block of quantized residuals by entropy decoding a first part of the bitstream;
- and
- based on the determination that transform skipping is enabled, reconstructing the block of residuals by one of rotating the block of quantized residuals and dequantizing the resulting rotated block or dequantizing the block of quantized residuals and rotating the resulting dequantized block.
A method of encoding video in a video encoder to output a bitstream of encoded data, the encoding including encoding residuals, the method comprising:
- determining that transform skipping is enabled for a block of residuals, meaning that no transform is to be applied during encoding and no inverse transform will be applied during decoding;
- based on the determination that transform skipping is enabled, producing a block of quantized residuals by one of either rotating the block of residuals and quantizing the resulting rotated block or quantizing the block of residuals and rotating the resulting quantized block;
- scanning, in a scan order, the block of quantized residuals to produce a first sequence of quantized residuals;
- and
- entropy encoding the first sequence of quantized residuals to generate a first part of the bitstream of encoded data.
A decoder for decoding a bitstream of encoded video to reconstruct a block of residuals, the decoder comprising:
- a processor;
- a memory;
- and
- a decoding application stored in memory and containing instructions that, when executed, cause the processor to:
- determine that transform skipping is enabled for the block of residuals, meaning that no transform was applied during encoding and no inverse transform will be applied during decoding;
- reconstruct based on a scan order, a block of quantized residuals by entropy decoding a first part of the bitstream;
- and
- based on the determination that transform skipping is enabled, reconstruct the block of residuals by one of rotating the block of quantized residuals and dequantizing the resulting rotated block or dequantizing the block of quantized residuals and rotating the resulting dequantized block.
An encoder for encoding video to output a bitstream of encoded data, the video including a block of residuals, the decoder comprising:
- a processor;
- a memory;
- and
- an encoding application stored in memory and containing instructions that, when executed, cause the processor to:
- determine that transform skipping is enabled for the block of residuals, meaning that no transform is to be applied during encoding and no inverse transform will be applied during decoding;
- based on the determination that transform skipping is enabled, produce a block of quantized coefficients by one of either rotating the block of residuals and quantizing the resulting rotated block or quantizing the block of residuals and rotating the resulting quantized block;
- scan, in a scan order, the block of quantized residuals to produce a sequence of quantized residuals;
- and
- entropy encode the sequence of quantized residuals to generate a part of the bitstream of encoded data.
A non-transitory processor-readable medium storing processor-executable instructions which, when executed, configures one or more processors to decode a bitstream of encoded video in a video decoder to reconstruct residuals, by performing the method of:
- determining that transform skipping is enabled for a block of residuals, meaning that no transform was applied during encoding and no inverse transform will be applied during decoding;
- reconstructing, based on a scan order, a block of quantized residuals by entropy decoding a first part of the bitstream;
- and
- based on the determination that transform skipping is enabled, reconstructing the block of residuals by one of rotating the block of quantized residuals and dequantizing the resulting rotated block or dequantizing the block of quantized residuals and rotating the resulting dequantized block.
Dependencies are inferred from the claim text.