mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2026-10-28 18:15:24 +08:00
François Doray
9badbee44d
In Chrome-branded builds, libavcodec/h274.c places 700,440 bytes of film grain buffers in chrome.dll's .bss (`film_grain_db` at 692,248 B and `init_slice_c::tmp` at 8,192 B), even though these buffers are only touched when software H.264 decoding encounters an H.274 Film Grain Characteristics SEI. On Windows, the PE loader pre-commits chrome.dll's entire .bss in every process. Move `init_slice_c::tmp` into `H274FilmGrainDatabase` (700,440 B total) and allocate `film_grain_db` on the heap via `ff_thread_once()` on the first call to `ff_h274_apply_film_grain()`. This is safe because: - `ff_h274_apply_film_grain()` is the sole entry point that accesses `film_grain_db`. Its callers in `h264_picture.c` and `vvc/dec.c` already handle negative error returns (`AVERROR(ENOMEM)`), and this CL updates `hevc_frame_end()` in `hevc/hevcdec.c` to propagate negative returns instead of asserting `ret >= 0`. - `init_slice_c()` is only called while holding `init_slice()`'s static mutex, so storing `tmp` in `H274FilmGrainDatabase` preserves the same thread safety without a large stack allocation. Impact (Windows x64 official Chrome-branded chrome.dll): - .data VirtualSize: 3,758,744 B -> 3,058,328 B (-684 KiB / ~-9.1 MiB at p50 process count). - Binary file size (.text/.data RawSize): +0 B.
82 lines
2.7 KiB
C
82 lines
2.7 KiB
C
/*
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* H.274 film grain synthesis
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* Copyright (c) 2021 Niklas Haas <ffmpeg@haasn.xyz>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* H.274 film grain synthesis.
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* @author Niklas Haas <ffmpeg@haasn.xyz>
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*/
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#ifndef AVCODEC_H274_H
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#define AVCODEC_H274_H
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#include "libavutil/film_grain_params.h"
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/**
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* Check whether ff_h274_apply_film_grain() supports the given parameter combination.
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*
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* @param model_id model_id from AVFilmGrainParams to be supplied
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* @param pix_fmt pixel format of the frames to be supplied
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*/
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static inline int ff_h274_film_grain_params_supported(int model_id, enum AVPixelFormat pix_fmt)
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{
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return model_id == 0 && pix_fmt == AV_PIX_FMT_YUV420P;
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}
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// Synthesizes film grain on top of `in` and stores the result to `out`. `out`
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// must already have been allocated and set to the same size and format as
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// `in`.
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//
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// Returns a negative error code on error, such as invalid params or
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// AVERROR(ENOMEM). If ff_h274_film_grain_params_supported() indicated that the
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// parameters are supported and the arguments given to
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// ff_h274_film_grain_params_supported() coincide with actual values from the
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// frames and params, only AVERROR(ENOMEM) can be returned.
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int ff_h274_apply_film_grain(AVFrame *out, const AVFrame *in,
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const AVFilmGrainParams *params);
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typedef struct H274HashContext H274HashContext;
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typedef struct H274SEIPictureHash {
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int present;
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union {
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uint8_t md5[3][16];
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uint16_t crc[3];
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uint32_t checksum[3];
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};
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uint8_t hash_type;
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} H274SEIPictureHash;
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int ff_h274_hash_init(H274HashContext **c, int type);
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int ff_h274_hash_verify(H274HashContext *c, const H274SEIPictureHash *hash,
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const AVFrame *frame, int coded_width, int coded_height);
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void ff_h274_hash_freep(H274HashContext **c);
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typedef struct H274SEIFrameFieldInfo {
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int present;
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int picture_struct;
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uint8_t display_elemental_periods;
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uint8_t source_scan_type;
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uint8_t duplicate_flag;
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} H274SEIFrameFieldInfo;
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#endif /* AVCODEC_H274_H */
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