mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-21 10:55:51 +02:00
initial seek support
Originally committed as revision 2502 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Fabrice Bellard
parent
27f388aa24
commit
155e9ee909
@ -13,6 +13,9 @@
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#define AVI_MAX_RIFF_SIZE 0x40000000LL
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#define AVI_MASTER_INDEX_SIZE 256
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/* index flags */
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#define AVIIF_INDEX 0x10
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offset_t start_tag(ByteIOContext *pb, const char *tag);
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void end_tag(ByteIOContext *pb, offset_t start);
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@ -21,18 +21,33 @@
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#include "dv.h"
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//#define DEBUG
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//#define DEBUG_SEEK
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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 AVIIndexEntry {
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unsigned int flags;
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unsigned int pos;
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unsigned int cum_len; /* sum of all lengths before this packet */
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} AVIIndexEntry;
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typedef struct AVIStream {
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AVIIndexEntry *index_entries;
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int nb_index_entries;
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int index_entries_allocated_size;
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int frame_offset; /* current frame (video) or byte (audio) counter
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(used to compute the pts) */
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int scale;
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int rate;
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int sample_size; /* audio only data */
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int new_frame_offset; /* temporary storage (used during seek) */
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int cum_len; /* temporary storage (used during seek) */
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} AVIStream;
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typedef struct {
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int64_t riff_end;
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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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int index_loaded;
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DVDemuxContext* dv_demux;
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} AVIContext;
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@ -74,8 +89,11 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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unsigned int size, nb_frames;
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int i, n;
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AVStream *st;
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AVIStream *ast;
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int xan_video = 0; /* hack to support Xan A/V */
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av_set_pts_info(s, 64, 1, AV_TIME_BASE);
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if (get_riff(avi, pb) < 0)
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return -1;
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@ -100,7 +118,8 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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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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avi->movi_list = url_ftell(pb) - 4;
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avi->movi_end = avi->movi_list + size;
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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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@ -115,9 +134,14 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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url_fskip(pb, 4 * 4);
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n = get_le32(pb);
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for(i=0;i<n;i++) {
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AVIStream *ast;
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st = av_new_stream(s, i);
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if (!st)
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goto fail;
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ast = av_mallocz(sizeof(AVIStream));
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if (!ast)
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goto fail;
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st->priv_data = ast;
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}
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url_fskip(pb, size - 7 * 4);
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break;
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@ -159,7 +183,8 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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}
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st = s->streams[stream_index];
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ast = st->priv_data;
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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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@ -168,27 +193,28 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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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;
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st->codec.frame_rate_base = scale;
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}else if(frame_period){
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st->codec.frame_rate = 1000000;
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st->codec.frame_rate_base = frame_period;
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rate = 1000000;
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scale = frame_period;
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}else{
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st->codec.frame_rate = 25;
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st->codec.frame_rate_base = 1;
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rate = 25;
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scale = 1;
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}
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ast->rate = rate;
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ast->scale = scale;
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st->codec.frame_rate = rate;
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st->codec.frame_rate_base = scale;
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get_le32(pb); /* start */
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nb_frames = get_le32(pb);
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st->start_time = 0;
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st->duration = (double)nb_frames *
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st->codec.frame_rate_base * AV_TIME_BASE /
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st->codec.frame_rate;
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url_fskip(pb, size - 9 * 4);
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break;
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case MKTAG('a', 'u', 'd', 's'):
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{
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unsigned int length, rate;
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unsigned int length;
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codec_type = CODEC_TYPE_AUDIO;
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@ -197,19 +223,23 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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break;
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}
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st = s->streams[stream_index];
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ast = st->priv_data;
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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); /* initial frame */
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get_le32(pb); /* scale */
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rate = get_le32(pb);
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ast->scale = get_le32(pb); /* scale */
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ast->rate = get_le32(pb);
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get_le32(pb); /* start */
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length = get_le32(pb); /* length, in samples or bytes */
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get_le32(pb); /* buffer size */
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get_le32(pb); /* quality */
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ast->sample_size = get_le32(pb); /* sample ssize */
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st->start_time = 0;
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if (rate != 0)
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st->duration = (int64_t)length * AV_TIME_BASE / rate;
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url_fskip(pb, size - 9 * 4);
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if (ast->rate != 0)
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st->duration = (int64_t)length * AV_TIME_BASE / ast->rate;
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url_fskip(pb, size - 12 * 4);
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}
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break;
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default:
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@ -274,6 +304,9 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
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url_fskip(pb, 1);
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/* special case time: To support Xan DPCM, hardcode
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* the format if Xxan is the video codec */
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st->need_parsing = 1;
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/* force parsing as several audio frames can be in
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one packet */
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if (xan_video)
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st->codec.codec_id = CODEC_ID_XAN_DPCM;
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break;
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@ -377,10 +410,31 @@ static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
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size = dv_produce_packet(avi->dv_demux, pkt,
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pkt->data, pkt->size);
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pkt->destruct = dstr;
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pkt->flags |= PKT_FLAG_KEY;
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} else {
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AVStream *st;
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AVIStream *ast;
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st = s->streams[n];
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ast = st->priv_data;
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/* XXX: how to handle B frames in avi ? */
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pkt->pts = ((int64_t)ast->frame_offset * ast->scale* AV_TIME_BASE) / ast->rate;
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pkt->stream_index = n;
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pkt->flags |= PKT_FLAG_KEY; // FIXME: We really should read
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// index for that
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/* FIXME: We really should read index for that */
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if (st->codec.codec_type == CODEC_TYPE_VIDEO) {
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if (ast->frame_offset < ast->nb_index_entries) {
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if (ast->index_entries[ast->frame_offset].flags & AVIIF_INDEX)
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pkt->flags |= PKT_FLAG_KEY;
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} else {
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/* if no index, better to say that all frames
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are key frames */
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pkt->flags |= PKT_FLAG_KEY;
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}
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ast->frame_offset++;
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} else {
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ast->frame_offset += pkt->size;
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pkt->flags |= PKT_FLAG_KEY;
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}
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}
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return size;
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}
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@ -388,6 +442,214 @@ static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
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return -1;
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}
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/* XXX: we make the implicit supposition that the position are sorted
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for each stream */
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static int avi_read_idx1(AVFormatContext *s, int size)
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{
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ByteIOContext *pb = &s->pb;
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int nb_index_entries, i;
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AVStream *st;
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AVIStream *ast;
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AVIIndexEntry *ie, *entries;
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unsigned int index, tag, flags, pos, len;
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nb_index_entries = size / 16;
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if (nb_index_entries <= 0)
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return -1;
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/* read the entries and sort them in each stream component */
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for(i = 0; i < nb_index_entries; i++) {
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tag = get_le32(pb);
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flags = get_le32(pb);
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pos = get_le32(pb);
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len = get_le32(pb);
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#if defined(DEBUG_SEEK) && 0
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printf("%d: tag=0x%x flags=0x%x pos=0x%x len=%d\n",
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i, tag, flags, pos, len);
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#endif
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index = ((tag & 0xff) - '0') * 10;
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index += ((tag >> 8) & 0xff) - '0';
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if (index >= s->nb_streams)
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continue;
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st = s->streams[index];
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ast = st->priv_data;
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entries = av_fast_realloc(ast->index_entries,
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&ast->index_entries_allocated_size,
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(ast->nb_index_entries + 1) *
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sizeof(AVIIndexEntry));
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if (entries) {
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ast->index_entries = entries;
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ie = &entries[ast->nb_index_entries++];
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ie->flags = flags;
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ie->pos = pos;
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ie->cum_len = ast->cum_len;
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ast->cum_len += len;
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}
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}
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return 0;
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}
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static int avi_load_index(AVFormatContext *s)
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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, size;
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url_fseek(pb, avi->movi_end, SEEK_SET);
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#ifdef DEBUG_SEEK
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printf("movi_end=0x%llx\n", avi->movi_end);
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#endif
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for(;;) {
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if (url_feof(pb))
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break;
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tag = get_le32(pb);
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size = get_le32(pb);
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#ifdef DEBUG_SEEK
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printf("tag=%c%c%c%c size=0x%x\n",
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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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#endif
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switch(tag) {
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case MKTAG('i', 'd', 'x', '1'):
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if (avi_read_idx1(s, size) < 0)
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goto skip;
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else
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goto the_end;
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break;
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default:
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skip:
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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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the_end:
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return 0;
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}
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/* return the index entry whose position is immediately >= 'wanted_pos' */
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static int locate_frame_in_index(AVIIndexEntry *entries,
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int nb_entries, int wanted_pos)
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{
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int a, b, m, pos;
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a = 0;
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b = nb_entries - 1;
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while (a <= b) {
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m = (a + b) >> 1;
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pos = entries[m].pos;
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if (pos == wanted_pos)
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goto found;
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else if (pos > wanted_pos) {
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b = m - 1;
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} else {
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a = m + 1;
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}
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}
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m = a;
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if (m > 0)
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m--;
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found:
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return m;
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}
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static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp)
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{
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AVIContext *avi = s->priv_data;
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AVStream *st;
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AVIStream *ast;
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int frame_number, i;
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int64_t pos;
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if (!avi->index_loaded) {
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/* we only load the index on demand */
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avi_load_index(s);
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avi->index_loaded = 1;
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}
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if (stream_index < 0) {
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for(i = 0; i < s->nb_streams; i++) {
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st = s->streams[i];
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if (st->codec.codec_type == CODEC_TYPE_VIDEO)
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goto found;
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}
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return -1;
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found:
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stream_index = i;
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}
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st = s->streams[stream_index];
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if (st->codec.codec_type != CODEC_TYPE_VIDEO)
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return -1;
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ast = st->priv_data;
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/* compute the frame number */
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frame_number = (timestamp * ast->rate) /
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(ast->scale * (int64_t)AV_TIME_BASE);
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#ifdef DEBUG_SEEK
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printf("timestamp=%0.3f nb_indexes=%d frame_number=%d\n",
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(double)timestamp / AV_TIME_BASE,
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ast->nb_index_entries, frame_number);
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#endif
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/* find a closest key frame before */
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if (frame_number >= ast->nb_index_entries)
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return -1;
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while (frame_number >= 0 &&
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!(ast->index_entries[frame_number].flags & AVIIF_INDEX))
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frame_number--;
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if (frame_number < 0)
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return -1;
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ast->new_frame_offset = frame_number;
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/* find the position */
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pos = ast->index_entries[frame_number].pos;
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#ifdef DEBUG_SEEK
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printf("key_frame_number=%d pos=0x%llx\n",
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frame_number, pos);
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#endif
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/* update the frame counters for all the other stream by looking
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at the positions just after the one found */
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for(i = 0; i < s->nb_streams; i++) {
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int j;
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if (i != stream_index) {
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st = s->streams[i];
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ast = st->priv_data;
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if (ast->nb_index_entries <= 0)
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return -1;
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j = locate_frame_in_index(ast->index_entries,
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ast->nb_index_entries,
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pos);
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/* get next frame */
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if ((j + 1) < ast->nb_index_entries)
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j++;
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/* extract the current frame number */
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if (st->codec.codec_type == CODEC_TYPE_VIDEO)
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ast->new_frame_offset = j;
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else
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ast->new_frame_offset = ast->index_entries[j].cum_len;
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}
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}
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/* everything is OK now. We can update the frame offsets */
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for(i = 0; i < s->nb_streams; i++) {
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st = s->streams[i];
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ast = st->priv_data;
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ast->frame_offset = ast->new_frame_offset;
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#ifdef DEBUG_SEEK
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printf("%d: frame_offset=%d\n", i,
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ast->frame_offset);
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#endif
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}
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/* do the seek */
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pos += avi->movi_list;
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url_fseek(&s->pb, pos, SEEK_SET);
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return 0;
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}
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static int avi_read_close(AVFormatContext *s)
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{
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int i;
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@ -395,7 +657,9 @@ static int avi_read_close(AVFormatContext *s)
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for(i=0;i<s->nb_streams;i++) {
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AVStream *st = s->streams[i];
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// av_free(st->priv_data);
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AVIStream *ast = st->priv_data;
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av_free(ast->index_entries);
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av_free(ast);
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av_free(st->codec.extradata);
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av_free(st->codec.palctrl);
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}
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@ -428,6 +692,7 @@ static AVInputFormat avi_iformat = {
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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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avi_read_seek,
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};
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int avidec_init(void)
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