mirror of https://git.ffmpeg.org/ffmpeg.git
117 lines
3.6 KiB
C
117 lines
3.6 KiB
C
/*
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* DNxHD/VC-3 parser
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* Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
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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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* DNxHD/VC-3 parser
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*/
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#include "parser.h"
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#define DNXHD_HEADER_PREFIX 0x000002800100
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typedef struct {
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ParseContext pc;
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int interlaced;
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int cur_field; /* first field is 0, second is 1 */
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} DNXHDParserContext;
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static int dnxhd_find_frame_end(DNXHDParserContext *dctx,
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const uint8_t *buf, int buf_size)
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{
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ParseContext *pc = &dctx->pc;
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uint64_t state = pc->state64;
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int pic_found = pc->frame_start_found;
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int i = 0;
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int interlaced = dctx->interlaced;
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int cur_field = dctx->cur_field;
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if (!pic_found) {
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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 & 0xffffffffff00LL) == DNXHD_HEADER_PREFIX) {
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i++;
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pic_found = 1;
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interlaced = (state&2)>>1; /* byte following the 5-byte header prefix */
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cur_field = state&1;
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break;
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}
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}
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}
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if (pic_found) {
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if (!buf_size) /* EOF considered as end of frame */
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return 0;
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for (; i < buf_size; i++) {
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state = (state << 8) | buf[i];
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if ((state & 0xffffffffff00LL) == DNXHD_HEADER_PREFIX) {
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if (!interlaced || dctx->cur_field) {
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pc->frame_start_found = 0;
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pc->state64 = -1;
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dctx->interlaced = interlaced;
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dctx->cur_field = 0;
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return i - 5;
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} else {
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/* continue, to get the second field */
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dctx->interlaced = interlaced = (state&2)>>1;
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dctx->cur_field = cur_field = state&1;
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}
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}
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}
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}
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pc->frame_start_found = pic_found;
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pc->state64 = state;
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dctx->interlaced = interlaced;
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dctx->cur_field = cur_field;
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return END_NOT_FOUND;
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}
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static int dnxhd_parse(AVCodecParserContext *s,
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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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DNXHDParserContext *dctx = s->priv_data;
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ParseContext *pc = &dctx->pc;
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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 = dnxhd_find_frame_end(dctx, 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 ff_dnxhd_parser = {
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.codec_ids = { AV_CODEC_ID_DNXHD },
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.priv_data_size = sizeof(DNXHDParserContext),
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.parser_parse = dnxhd_parse,
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.parser_close = ff_parse_close,
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};
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