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FFmpeg/libavcodec/h274.h
Andreas Rheinhardt 14015b9e15 avcodec/hevcdec: Check early whether film grain is supported, fix race
Applying film grain happens after ff_thread_finish_setup(),
so the parameters synced in hevc_update_thread_context() must not
be modified. But this is exactly what happens in case applying
film grain fails. (The likely result is that in case of frame threading
an uninitialized frame is output.)

Given that it is actually very easy to know in advance whether
ff_h274_apply_film_grain() supports a given set of parameters,
one can check for this before ff_thread_finish_setup()
and avoid allocating an unused buffer lateron.

Reviewed-by: Niklas Haas <ffmpeg@haasn.xyz>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2023-09-26 21:06:14 +02:00

68 lines
2.4 KiB
C

/*
* H.274 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
* H.274 film grain synthesis.
* @author Niklas Haas <ffmpeg@haasn.xyz>
*/
#ifndef AVCODEC_H274_H
#define AVCODEC_H274_H
#include "libavutil/film_grain_params.h"
// Must be initialized to {0} prior to first usage
typedef struct H274FilmGrainDatabase {
// Database of film grain patterns, lazily computed as-needed
int8_t db[13 /* h */][13 /* v */][64][64];
uint16_t residency[13 /* h */]; // bit field of v
// Temporary buffer for slice generation
int16_t slice_tmp[64][64];
} H274FilmGrainDatabase;
/**
* Check whether ff_h274_apply_film_grain() supports the given parameter combination.
*
* @param model_id model_id from AVFilmGrainParams to be supplied
* @param pix_fmt pixel format of the frames to be supplied
*/
static inline int ff_h274_film_grain_params_supported(int model_id, enum AVPixelFormat pix_fmt)
{
return model_id == 0 && pix_fmt == AV_PIX_FMT_YUV420P;
}
// 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`.
//
// Returns a negative error code on error, such as invalid params.
// If ff_h274_film_grain_params_supported() indicated that the parameters
// are supported, no error will be returned if the arguments given to
// ff_h274_film_grain_params_supported() coincide with actual values
// from the frames and params.
int ff_h274_apply_film_grain(AVFrame *out, const AVFrame *in,
H274FilmGrainDatabase *db,
const AVFilmGrainParams *params);
#endif /* AVCODEC_H274_H */