mirror of
https://github.com/FFmpeg/FFmpeg.git
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106 lines
2.9 KiB
C
106 lines
2.9 KiB
C
/*
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* CRI parser
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* Copyright (c) 2021 Paul B Mahol
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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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* CRI parser
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*/
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#include "libavutil/bswap.h"
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#include "libavutil/common.h"
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#include "parser.h"
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typedef struct CRIParser {
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ParseContext pc;
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int count;
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int chunk;
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int read_bytes;
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int skip_bytes;
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} CRIParser;
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#define KEY (((uint64_t)'\1' << 56) | ((uint64_t)'\0' << 48) | \
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((uint64_t)'\0' << 40) | ((uint64_t)'\0' << 32) | \
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((uint64_t)'\4' << 24) | ((uint64_t)'\0' << 16) | \
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((uint64_t)'\0' << 8) | ((uint64_t)'\0' << 0))
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static int cri_parse(AVCodecParserContext *s, AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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CRIParser *bpc = s->priv_data;
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uint64_t state = bpc->pc.state64;
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int next = END_NOT_FOUND, i = 0;
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s->pict_type = AV_PICTURE_TYPE_I;
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s->key_frame = 1;
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s->duration = 1;
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*poutbuf_size = 0;
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*poutbuf = NULL;
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for (; i < buf_size; i++) {
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state = (state << 8) | buf[i];
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bpc->read_bytes++;
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if (bpc->skip_bytes > 0) {
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bpc->skip_bytes--;
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if (bpc->skip_bytes == 0)
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bpc->read_bytes = 0;
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} else {
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if (state != KEY)
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continue;
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}
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if (bpc->skip_bytes == 0 && bpc->read_bytes >= 8) {
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bpc->skip_bytes = av_bswap32(state & 0xFFFFFFFF);
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bpc->chunk = state >> 32;
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bpc->read_bytes = 0;
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bpc->count++;
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}
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if (bpc->chunk == 0x01000000 && bpc->skip_bytes == 4 &&
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bpc->read_bytes == 0 && bpc->count > 1) {
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next = i - 7;
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break;
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}
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}
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bpc->pc.state64 = state;
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if (ff_combine_frame(&bpc->pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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AVCodecParser ff_cri_parser = {
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.codec_ids = { AV_CODEC_ID_CRI },
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.priv_data_size = sizeof(CRIParser),
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.parser_parse = cri_parse,
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.parser_close = ff_parse_close,
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};
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