FFmpeg

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Author	SHA1	Message	Date
Niklas Haas	f50382cba6	avcodec/aom_film_grain: implement AFGS1 parsing Based on the AOMedia Film Grain Synthesis 1 (AFGS1) spec: https://aomediacodec.github.io/afgs1-spec/ The parsing has been changed substantially relative to the AV1 film grain OBU. In particular: 1. There is the possibility of maintaining multiple independent film grain parameter sets, and decoders/players are recommended to pick the one most appropriate for the intended display resolution. This could also be used to e.g. switch between different grain profiles without having to re-signal the appropriate coefficients. 2. Supporting this, it's possible to predict the grain coefficients from previously signalled parameter sets, transmitting only the residual. 3. When not predicting, the parameter sets are now stored as a series of increments, rather than being directly transmitted. 4. There are several new AFGS1-exclusive fields. I placed this parser in its own file, rather than h2645_sei.c, since nothing in the generic AFGS1 film grain payload is specific to T.35, and to compartmentalize the code base.	12 months ago
Niklas Haas	1535d33818	avcodec/aom_film_grain: add AOM film grain synthesis Implementation copied wholesale from dav1d, sans SIMD, under permissive license. This implementation was extensively verified to be bit-exact, so it serves as a much better starting point than trying to re-engineer this from scratch for no reason. (I also authored the original implementation in dav1d, so any "clean room" implementation would end up looking much the same, anyway) The notable changes I had to make while adapting this from the dav1d code-base to the FFmpeg codebase include: - reordering variable declarations to avoid triggering warnings - replacing several inline helpers by avutil equivalents - changing code that accesses frame metadata - replacing raw plane copying logic by av_image_copy_plane Apart from this, the implementation is basically unmodified.	12 months ago

Author

SHA1

Message

Date

Niklas Haas

f50382cba6

avcodec/aom_film_grain: implement AFGS1 parsing

Based on the AOMedia Film Grain Synthesis 1 (AFGS1) spec:
  https://aomediacodec.github.io/afgs1-spec/

The parsing has been changed substantially relative to the AV1 film
grain OBU. In particular:

1. There is the possibility of maintaining multiple independent film
   grain parameter sets, and decoders/players are recommended to pick
   the one most appropriate for the intended display resolution. This
   could also be used to e.g. switch between different grain profiles
   without having to re-signal the appropriate coefficients.

2. Supporting this, it's possible to *predict* the grain coefficients
   from previously signalled parameter sets, transmitting only the
   residual.

3. When not predicting, the parameter sets are now stored as a series of
   increments, rather than being directly transmitted.

4. There are several new AFGS1-exclusive fields.

I placed this parser in its own file, rather than h2645_sei.c, since
nothing in the generic AFGS1 film grain payload is specific to T.35, and
to compartmentalize the code base.

12 months ago

Niklas Haas

1535d33818

avcodec/aom_film_grain: add AOM film grain synthesis

Implementation copied wholesale from dav1d, sans SIMD, under permissive
license. This implementation was extensively verified to be bit-exact,
so it serves as a much better starting point than trying to re-engineer
this from scratch for no reason. (I also authored the original
implementation in dav1d, so any "clean room" implementation would end up
looking much the same, anyway)

The notable changes I had to make while adapting this from the dav1d
code-base to the FFmpeg codebase include:

- reordering variable declarations to avoid triggering warnings
- replacing several inline helpers by avutil equivalents
- changing code that accesses frame metadata
- replacing raw plane copying logic by av_image_copy_plane

Apart from this, the implementation is basically unmodified.

12 months ago

2 Commits (dedc2456bf97003323fbfd61f94a6b345062e7d4)