Enhancements of the AV1 video codec
AssigneeFastVDO LLC
InventorsPankaj N. Topiwala, Wei Dai, Madhu Peringassery Krishnan
Life of this patent
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Abstract
Encoding and decoding systems disclosed enhance the AV1/VPX codecs in the context of 8-bit SDR video and 10-bit HDR video content, for applications including streaming and high quality coding for content contribution editing. For SDR content, lapped biorthogonal transforms for near lossless applications and used and optimized resampling filter pairs for adaptive resolution coding in streaming applications are used. For HDR content, a data adaptive grading technique in conjunction with the VP9/VP10 encoder may be used. The encoding/decoding system provides substantial value in the coding of HDR content, and provides backward compatibility with SDR.
Claims20
A method of encoding videos comprising:
- receiving, by a source device, a first signal representing a video and having a first dynamic range;
- processing, by the source device, the first signal to generate a second signal and metadata, the second signal having a second dynamic range, the second dynamic range being smaller than the first dynamic range, the metadata enabling a decoder to produce a high-quality third signal with the first dynamic range based on the second signal, comprising:
- extracting, from the first signal, a luminance signal;
- smoothing the luminance signal to generate a smoothed luminance signal, based upon a difference between the first dynamic range and the second dynamic range;
- generating the second signal based on a preliminary second signal generated by dividing the first signal by the smoothed luminance signal;
- and
- encoding, by the source device, the second signal and the metadata into a combined bitstream.
A non-transitory computer-readable storage medium comprising instructions that when executed by a processor cause the processor to:
- receive a first signal representing a video and having a first dynamic range;
- process the first signal to generate a second signal and metadata, the second signal having a second dynamic range, the second dynamic range being smaller than the first dynamic range, the metadata enabling a decoder to produce a high-quality third signal with the first dynamic range based on the second signal, comprising:
- extracting, from the first signal, a luminance signal;
- smoothing the luminance signal to generate a smoothed luminance signal, based upon a difference between the first dynamic range and the second dynamic range;
- generating the second signal based on a preliminary second signal generated by dividing the first signal by the smoothed luminance signal;
- and
- encode the second signal and the metadata into a combined bitstream.
A method of decoding a coded high dynamic range bitstream comprising:
- receiving a combined bitstream;
- decoding the combined bitstream to obtain a first signal and metadata, the first signal having a first dynamic range;
- obtaining a smoothed luminance signal based on the metadata;
- regrading the first signal using inverse adaptive monotonic nonlinear mapping with data adaptive tuning;
- and
- generating a second signal by multiplying the regraded first signal by the smoothed luminance signal, the second signal having a second dynamic range, the second dynamic range being larger than the first dynamic range, the second signal representing a video.
Dependencies are inferred from the claim text.