89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
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/*
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* Dirac parser
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*
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* Copyright (c) 2007 Marco Gerards <marco@gnu.org>
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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 dirac_parser.c
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* Dirac Parser
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* @author Marco Gerards <marco@gnu.org>
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*/
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#include "parser.h"
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#define DIRAC_PARSE_INFO_PREFIX 0x42424344
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/**
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* Finds the end of the current frame in the bitstream.
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* @return the position of the first byte of the next frame or -1
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*/
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static int find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
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{
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uint32_t state = pc->state;
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int i;
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for (i = 0; i < buf_size; i++) {
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state = (state << 8) | buf[i];
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if (state == DIRAC_PARSE_INFO_PREFIX) {
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pc->frame_start_found ^= 1;
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if (!pc->frame_start_found) {
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pc->state = -1;
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return i - 3;
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}
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}
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}
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pc->state = state;
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return END_NOT_FOUND;
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}
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static int dirac_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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ParseContext *pc = s->priv_data;
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int next;
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if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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next = buf_size;
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}else{
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next = find_frame_end(pc, buf, buf_size);
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if (ff_combine_frame(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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}
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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 dirac_parser = {
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{ CODEC_ID_DIRAC },
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sizeof(ParseContext),
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NULL,
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dirac_parse,
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ff_parse_close,
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};
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