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FFmpeg/libavcodec/aom_film_grain.h
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.
2024-03-23 18:55:21 +01:00

52 lines
1.8 KiB
C

/*
* AOM film grain synthesis
* Copyright (c) 2021 Niklas Haas <ffmpeg@haasn.xyz>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* AOM film grain synthesis.
* @author Niklas Haas <ffmpeg@haasn.xyz>
*/
#ifndef AVCODEC_AOM_FILM_GRAIN_H
#define AVCODEC_AOM_FILM_GRAIN_H
#include "libavutil/film_grain_params.h"
typedef struct AVFilmGrainAFGS1Params {
int enable;
AVFilmGrainParams sets[8];
} AVFilmGrainAFGS1Params;
// Synthesizes film grain on top of `in` and stores the result to `out`. `out`
// must already have been allocated and set to the same size and format as `in`.
int ff_aom_apply_film_grain(AVFrame *out, const AVFrame *in,
const AVFilmGrainParams *params);
// Parse AFGS1 parameter sets from an ITU-T T.35 payload. Returns 0 on success,
// or a negative error code.
int ff_aom_parse_film_grain_sets(AVFilmGrainAFGS1Params *s,
const uint8_t *payload, int payload_size);
// Attach all valid film grain param sets to `frame`.
int ff_aom_attach_film_grain_sets(const AVFilmGrainAFGS1Params *s, AVFrame *frame);
#endif /* AVCODEC_AOM_FILM_GRAIN_H */