mirror of https://git.ffmpeg.org/ffmpeg.git
306 lines
9.0 KiB
C
306 lines
9.0 KiB
C
/*
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* AVI decoder.
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* Copyright (c) 2001 Fabrice Bellard.
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*
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* This library 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 of the License, or (at your option) any later version.
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*
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* This library 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 this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "avformat.h"
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#include "avi.h"
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//#define DEBUG
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typedef struct AVIIndex {
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unsigned char tag[4];
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unsigned int flags, pos, len;
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struct AVIIndex *next;
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} AVIIndex;
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typedef struct {
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int64_t movi_end;
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offset_t movi_list;
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AVIIndex *first, *last;
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} AVIContext;
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#ifdef DEBUG
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static void print_tag(const char *str, unsigned int tag, int size)
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{
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printf("%s: tag=%c%c%c%c size=0x%x\n",
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str, tag & 0xff,
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(tag >> 8) & 0xff,
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(tag >> 16) & 0xff,
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(tag >> 24) & 0xff,
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size);
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}
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#endif
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static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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AVIContext *avi = s->priv_data;
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ByteIOContext *pb = &s->pb;
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uint32_t tag, tag1;
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int codec_type, stream_index, frame_period, bit_rate, scale, rate;
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unsigned int size;
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int i;
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AVStream *st;
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/* check RIFF header */
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tag = get_le32(pb);
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if (tag != MKTAG('R', 'I', 'F', 'F'))
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return -1;
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get_le32(pb); /* file size */
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tag = get_le32(pb);
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if (tag != MKTAG('A', 'V', 'I', ' '))
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return -1;
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/* first list tag */
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stream_index = -1;
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codec_type = -1;
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frame_period = 0;
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for(;;) {
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if (url_feof(pb))
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goto fail;
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tag = get_le32(pb);
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size = get_le32(pb);
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#ifdef DEBUG
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print_tag("tag", tag, size);
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#endif
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switch(tag) {
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case MKTAG('L', 'I', 'S', 'T'):
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/* ignored, except when start of video packets */
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tag1 = get_le32(pb);
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#ifdef DEBUG
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print_tag("list", tag1, 0);
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#endif
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if (tag1 == MKTAG('m', 'o', 'v', 'i')) {
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avi->movi_end = url_ftell(pb) + size - 4;
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#ifdef DEBUG
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printf("movi end=%Lx\n", avi->movi_end);
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#endif
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goto end_of_header;
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}
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break;
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case MKTAG('a', 'v', 'i', 'h'):
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/* avi header */
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/* using frame_period is bad idea */
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frame_period = get_le32(pb);
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bit_rate = get_le32(pb) * 8;
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url_fskip(pb, 4 * 4);
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s->nb_streams = get_le32(pb);
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for(i=0;i<s->nb_streams;i++) {
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AVStream *st = av_mallocz(sizeof(AVStream));
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if (!st)
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goto fail;
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avcodec_get_context_defaults(&st->codec);
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s->streams[i] = st;
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}
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url_fskip(pb, size - 7 * 4);
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break;
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case MKTAG('s', 't', 'r', 'h'):
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/* stream header */
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stream_index++;
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tag1 = get_le32(pb);
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switch(tag1) {
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case MKTAG('v', 'i', 'd', 's'):
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codec_type = CODEC_TYPE_VIDEO;
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if (stream_index >= s->nb_streams) {
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url_fskip(pb, size - 4);
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break;
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}
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st = s->streams[stream_index];
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get_le32(pb); /* codec tag */
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get_le32(pb); /* flags */
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get_le16(pb); /* priority */
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get_le16(pb); /* language */
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get_le32(pb); /* XXX: initial frame ? */
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scale= get_le32(pb); /* scale */
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rate= get_le32(pb); /* rate */
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if(scale && rate)
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st->codec.frame_rate= (rate * (uint64_t)FRAME_RATE_BASE + scale/2) / scale;
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else if(frame_period)
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st->codec.frame_rate = (1000000LL * FRAME_RATE_BASE + frame_period/2) / frame_period;
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else
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st->codec.frame_rate = 25 * FRAME_RATE_BASE;
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url_fskip(pb, size - 7 * 4);
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break;
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case MKTAG('a', 'u', 'd', 's'):
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codec_type = CODEC_TYPE_AUDIO;
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/* nothing really useful */
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url_fskip(pb, size - 4);
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break;
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default:
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goto fail;
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}
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break;
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case MKTAG('s', 't', 'r', 'f'):
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/* stream header */
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if (stream_index >= s->nb_streams) {
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url_fskip(pb, size);
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} else {
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st = s->streams[stream_index];
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switch(codec_type) {
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case CODEC_TYPE_VIDEO:
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get_le32(pb); /* size */
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st->codec.width = get_le32(pb);
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st->codec.height = get_le32(pb);
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get_le16(pb); /* panes */
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st->codec.bits_per_sample= get_le16(pb); /* depth */
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tag1 = get_le32(pb);
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get_le32(pb); /* ImageSize */
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get_le32(pb); /* XPelsPerMeter */
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get_le32(pb); /* YPelsPerMeter */
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get_le32(pb); /* ClrUsed */
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get_le32(pb); /* ClrImportant */
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st->codec.extradata_size= size - 10*4;
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st->codec.extradata= av_malloc(st->codec.extradata_size); //FIXME where should we free this?
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get_buffer(pb, st->codec.extradata, st->codec.extradata_size);
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if(st->codec.extradata_size & 1) //FIXME check if the encoder really did this correctly
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get_byte(pb);
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#ifdef DEBUG
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print_tag("video", tag1, 0);
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#endif
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st->codec.codec_type = CODEC_TYPE_VIDEO;
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st->codec.codec_tag = tag1;
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st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1);
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// url_fskip(pb, size - 5 * 4);
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break;
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case CODEC_TYPE_AUDIO:
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get_wav_header(pb, &st->codec, (size >= 18));
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if (size%2) /* 2-aligned (fix for Stargate SG-1 - 3x18 - Shades of Grey.avi) */
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url_fskip(pb, 1);
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break;
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default:
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url_fskip(pb, size);
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break;
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}
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}
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break;
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default:
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/* skip tag */
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size += (size & 1);
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url_fskip(pb, size);
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break;
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}
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}
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end_of_header:
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/* check stream number */
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if (stream_index != s->nb_streams - 1) {
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fail:
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for(i=0;i<s->nb_streams;i++) {
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av_freep(&s->streams[i]->codec.extradata);
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av_freep(&s->streams[i]);
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}
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return -1;
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}
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return 0;
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}
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static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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AVIContext *avi = s->priv_data;
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ByteIOContext *pb = &s->pb;
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int n, d[8], size, i;
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memset(d, -1, sizeof(int)*8);
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for(i=url_ftell(pb); (!url_feof(pb)) && i < avi->movi_end; i++){
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int j;
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for(j=0; j<7; j++)
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d[j]= d[j+1];
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d[7]= get_byte(pb);
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size= d[4] + (d[5]<<8) + (d[6]<<16) + (d[7]<<24);
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//parse ix##
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n= (d[2] - '0') * 10 + (d[3] - '0');
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if( d[2] >= '0' && d[2] <= '9'
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&& d[3] >= '0' && d[3] <= '9'
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&& d[0] == 'i' && d[1] == 'x'
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&& n < s->nb_streams
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&& i + size <= avi->movi_end){
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url_fskip(pb, size);
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}
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//parse ##dc/##wb
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n= (d[0] - '0') * 10 + (d[1] - '0');
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if( d[0] >= '0' && d[0] <= '9'
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&& d[1] >= '0' && d[1] <= '9'
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&&((d[2] == 'd' && d[3] == 'c') || (d[2] == 'w' && d[3] == 'b'))
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&& n < s->nb_streams
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&& i + size <= avi->movi_end){
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av_new_packet(pkt, size);
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pkt->stream_index = n;
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get_buffer(pb, pkt->data, pkt->size);
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if (size & 1)
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get_byte(pb);
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return 0;
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}
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}
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return -1;
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}
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static int avi_read_close(AVFormatContext *s)
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{
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return 0;
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}
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static int avi_probe(AVProbeData *p)
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{
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/* check file header */
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if (p->buf_size <= 32)
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return 0;
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if (p->buf[0] == 'R' && p->buf[1] == 'I' &&
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p->buf[2] == 'F' && p->buf[3] == 'F' &&
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p->buf[8] == 'A' && p->buf[9] == 'V' &&
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p->buf[10] == 'I' && p->buf[11] == ' ')
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return AVPROBE_SCORE_MAX;
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else
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return 0;
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}
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static AVInputFormat avi_iformat = {
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"avi",
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"avi format",
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sizeof(AVIContext),
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avi_probe,
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avi_read_header,
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avi_read_packet,
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avi_read_close,
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};
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int avidec_init(void)
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{
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av_register_input_format(&avi_iformat);
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return 0;
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}
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