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read and use index (based on a patch by John Donaghy on the 23-03-2006 '[Ffmpeg-devel] dvr-ms seek help request')

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Originally committed as revision 6054 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-08-23 17:07:01 +00:00
parent 052aa2ad3c
commit 56c96a229b
1 changed files with 77 additions and 2 deletions
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79
libavformat/asf.c
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@ -837,16 +837,91 @@ static int64_t asf_read_pts(AVFormatContext *s, int stream_index, int64_t *ppos,
return pts;
}
static void asf_build_simple_index(AVFormatContext *s, int stream_index)
{
GUID g;
ASFContext *asf = s->priv_data;
int64_t gsize, itime;
int64_t pos, current_pos, index_pts;
int i;
int pct,ict;
current_pos = url_ftell(&s->pb);
url_fseek(&s->pb, asf->data_object_offset + asf->data_object_size, SEEK_SET);
get_guid(&s->pb, &g);
if (!memcmp(&g, &index_guid, sizeof(GUID))) {
gsize = get_le64(&s->pb);
get_guid(&s->pb, &g);
itime=get_le64(&s->pb);
pct=get_le32(&s->pb);
ict=get_le32(&s->pb);
av_log(NULL, AV_LOG_DEBUG, "itime:0x%Lx, pct:%d, ict:%d\n",itime,pct,ict);
for (i=0;i<ict;i++){
int pktnum=get_le32(&s->pb);
int pktct =get_le16(&s->pb);
av_log(NULL, AV_LOG_DEBUG, "pktnum:%d, pktct:%d\n", pktnum, pktct);
pos=s->data_offset + asf->packet_size*(int64_t)pktnum;
index_pts=av_rescale(itime, i, 10000);
av_add_index_entry(s->streams[stream_index], pos, index_pts, asf->packet_size, 0, AVINDEX_KEYFRAME);
}
}
url_fseek(&s->pb, current_pos, SEEK_SET);
}
static int asf_read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags)
{
ASFContext *asf = s->priv_data;
AVStream *st = s->streams[stream_index];
int64_t pos;
int index;
if (asf->packet_size <= 0)
return -1;
if(av_seek_frame_binary(s, stream_index, pts, flags)<0)
return -1;
if (!st->index_entries)
asf_build_simple_index(s, stream_index);
if(!st->index_entries){
if(av_seek_frame_binary(s, stream_index, pts, flags)<0)
return -1;
}else{
index= av_index_search_timestamp(st, pts, flags);
if(index<0)
return -1;
/* find the position */
pos = st->index_entries[index].pos;
pts = st->index_entries[index].timestamp;
// various attempts to find key frame have failed so far
// asf_reset_header(s);
// url_fseek(&s->pb, pos, SEEK_SET);
// key_pos = pos;
// for(i=0;i<16;i++){
// pos = url_ftell(&s->pb);
// if (av_read_frame(s, &pkt) < 0){
// av_log(s, AV_LOG_INFO, "seek failed\n");
// return -1;
// }
// asf_st = s->streams[stream_index]->priv_data;
// pos += st->parser->frame_offset;
//
// if (pkt.size > b) {
// b = pkt.size;
// key_pos = pos;
// }
//
// av_free_packet(&pkt);
// }
/* do the seek */
av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %Ld\n", pos);
url_fseek(&s->pb, pos, SEEK_SET);
}
asf_reset_header(s);
return 0;
}