Adaptive loop filtering in accordance with video coding
View Patent ↗Adaptive loop filtering in accordance with video coding. An adaptive loop filter (ALF) and/or other in-loop filters (e.g., sample adaptive offset (SAO) filter, etc.) may be implemented within various video coding architectures (e.g., encoding and/or decoding architectures) to perform both offset and scaling processing, only scaling processing, and/or only offset processing. Operation of such an ALF may be selective in accordance with any of multiple respective operational modes at any given time and may be adaptive based upon various consideration(s) (e.g., desired complexity level, processing type, local and/or remote operational conditions, etc.). For example, an ALF may be applied to a decoded picture before it is stored in a picture buffer (or digital teacher buffer (DPB)). An ALF can provide for coding noise reduction of a decoded picture, and the filtering operations performed thereby may be selective (e.g., on a slice by slice basis, block by block basis, etc.).
1. An apparatus comprising:
a video encoder configured to encode an input video signal to generate an output bitstream that is representative of the input video signal, wherein the video encoder further includes:
at least one feedback loop having a sample adaptive offset (SAO) filter and an adaptive loop filter (ALF), wherein the ALF is configured to perform only scaling processing and the ALF is implemented to receive a SAO-filtered output signal from the SAO filter, and wherein:
the ALF is configured selectively to operate on a block by block basis or a slice by slice basis within the video encoder;
the apparatus configured to signal to at least one additional apparatus, which is implemented to receive the output bitstream, which subset of a plurality of blocks or which subset of a plurality of slices associated with the input video signal that have been selectively filtered by the ALF, wherein the at least one additional apparatus is implemented to receive the output bitstream and to decode the output bitstream to recover the input video signal; and
the ALF configured to perform only scaling processing to perform illumination compensation using at least one gain value to remove at least one amount of quantization noise during encoding of the input video signal to generate the output bitstream having at least one least one quality.
2. The apparatus of claim 1 further comprising:
the ALF selectively configured selectively to operate using scaling only processing, offset only processing, and both scaling and offset processing.
3. The apparatus of claim 1 , wherein the ALF is further configured to: perform illumination compensation using a first gain value to remove a first amount of quantization noise during encoding of the input video signal to generate the output bitstream at a first quality; and
perform illumination compensation using a second gain value to remove a second amount of quantization noise during encoding of the input video signal to generate the output bitstream at a second quality.
4. The apparatus of claim 1 further comprising:
a first communication device, wherein:
the at least one additional apparatus is a second communication device, which is in communication with the first communication device via at least one communication channel, including:
an input configured to receive the output bitstream; and
a video decoder configured to decode the output bitstream to generate an output video signal corresponding to the input video signal, wherein the video decoder including at least one additional feedback loop having at least one additional ALF configured to operate using only scaling processing, wherein the second communication device is at least one of computer, a laptop computer, a high definition (HD) television, a standard definition (SD) television, a handheld media unit, a set top box (STB), or a digital video disc (DVD) player.
5. The apparatus of claim 1 further comprising:
a communication device that is operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, a fiber-optic communication system, or a mobile communication system.
6. An apparatus comprising:
a video encoder configured to encode an input video signal to generate an output bitstream that is representative of the input video signal, wherein the video encoder further includes at least one feedback loop having an adaptive loop filter (ALF) configured to operate using only scaling processing, wherein the ALF configured to perform illumination compensation using at least one gain value to remove at least one amount of quantization noise during encoding of the input video signal to generate the output bitstream having at least one least one quality.
7. The apparatus of claim 6 further comprising:
the ALF is configured selectively to operate on a block by block basis or a slice by slice basis within the video encoder; and
the apparatus configured to signal to at least one additional apparatus, which is implemented to receive the output bitstream, which subset of a plurality of blocks or which subset of a plurality of slices associated with the input video signal that have been selectively filtered by the ALF, wherein the at least one additional apparatus is implemented to receive the output bitstream and to decode the output bitstream to recover the input video signal.
8. The apparatus of claim 6 further comprising:
a sample adaptive offset (SAO) filter that is also included within the at least one feedback loop having the ALF, and the ALF is implemented to receive a SAO-filtered output signal from the SAO filter; and
the ALF configured selectively to operate using scaling only processing, offset only processing, and both scaling and offset processing.
9. The apparatus of claim 6 further comprising:
a sample adaptive offset (SAO) filter that is also included within the at least one feedback loop having the ALF, and the ALF is implemented to receive a SAO-filtered output signal from the SAO filter.
10. The apparatus of claim 6 further comprising:
a sample adaptive offset (SAO) filter that is also included within the at least one feedback loop having the ALF, and the ALF is implemented to receive a SAO-filtered output signal from the SAO filter; and
the ALF configured to:
perform only scaling processing to perform illumination compensation using a first gain value to remove a first amount of quantization noise during encoding of the input video signal to generate the output bitstream at a first quality; and
perform only scaling processing to perform illumination compensation using a second gain value to remove a second amount of quantization noise during encoding of the input video signal to generate the output bitstream at a second quality.
11. The apparatus of claim 6 further comprising:
a first communication device, wherein:
a second communication device, which is in communication with the first communication device via at least one communication channel, including:
an input configured to receive the output bitstream; and
a video decoder configured to decode the output bitstream to generate an output video signal corresponding to the input video signal, wherein the video decoder including at least one additional feedback loop having at least one additional ALF configured to operate using only scaling processing.
12. The apparatus of claim 11 , wherein the second communication device is at least one of computer, a laptop computer, a high definition (HD) television, a standard definition (SD) television, a handheld media unit, a set top box (STB), or a digital video disc (DVD) player.
13. The apparatus of claim 6 further comprising:
a communication device that is operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, a fiber-optic communication system, or a mobile communication system.
14. A method for execution by a video encoder of a communication device, the method comprising:
operating the video encoder to encode an input video signal to generate an output bitstream that is representative of the input video signal; and
operating an adaptive loop filter (ALF) that is implemented within a at least one feedback loop of the video encoder using only scaling processing, wherein the ALF is included within a feedback loop of the video encoder including performing illumination compensation using at least one gain value to remove at least one amount of quantization noise during encoding of the input video signal to generate the output bitstream having at least one least one quality.
15. The method of claim 14 further comprising:
operating the ALF selectively on a block by block basis or a slice by slice basis within the video encoder; and
signaling from the communication device to at least one additional communication device, which is implemented to receive the output bitstream, which subset of a plurality of blocks or which subset of a plurality of slices associated with the input video signal that have been selectively filtered by the ALF, wherein the at least one additional communication device is implemented to receive the output bitstream and to decode the output bitstream to recover the input video signal.
16. The method of claim 14 further comprising:
operating a sample adaptive offset (SAO) filter, which is also included within the at least one feedback loop having the ALF, to generate and provide a SAO-filtered output signal to the ALF; and
operating the ALF selectively using scaling only processing, offset only processing, and both scaling and offset processing.
17. The method of claim 14 further comprising:
operating a sample adaptive offset (SAO) filter, which is also included within the at least one feedback loop having the ALF, to generate and provide a SAO-filtered output signal to the ALF.
18. The method of claim 14 further comprising:
operating a sample adaptive offset (SAO) filter, included within the at least one feedback loop having the ALF, to generate and provide a SAO-filtered output signal to the ALF; and
operating the ALF to perform only scaling processing to:
perform illumination compensation using a first gain value to remove a first amount of quantization noise during encoding of the input video signal to generate the output bitstream at a first quality; and
perform illumination compensation using a second gain value to remove a second amount of quantization noise during encoding of the input video signal to generate the output bitstream at a second quality.
19. The method of claim 14 further comprising:
operating an additional communication device, in communication with the communication device via at least one communication channel, by:
receiving the output bitstream; and
operating a video decoder to decode the output bitstream to generate an output video signal corresponding to the input video signal, wherein the video decoder including at least one additional feedback loop having at least one additional ALF operative using only scaling processing, wherein the additional communication device is at least one of computer, a laptop computer, a high definition (HD) television, a standard definition (SD) television, a handheld media unit, a set top box (STB), or a digital video disc (DVD) player.
20. The method of claim 14 , wherein the communication device is operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, a fiber-optic communication system, or a mobile communication system.