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use packet number instead of byte number internally for seeking

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Originally committed as revision 2704 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-01-14 18:40:29 +00:00
parent a602556e06
commit 09646bab63
1 changed files with 9 additions and 19 deletions
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28
libavformat/asf.c
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@ -1299,13 +1299,6 @@ static int asf_read_close(AVFormatContext *s)
return 0;
}
static int64_t asf_align(AVFormatContext *s, int64_t pos){
ASFContext *asf = s->priv_data;
assert(pos >= 0);
return pos/ asf->packet_size * asf->packet_size;
}
// Added to support seeking after packets have been read
// If information is not reset, read_packet fails due to
// leftover information from previous reads
@ -1354,10 +1347,8 @@ static int64_t asf_read_pts(AVFormatContext *s, int64_t *ppos, int stream_index)
int64_t pts;
int64_t pos= *ppos;
// ensure we are on the packet boundry
assert(pos % asf->packet_size == 0);
//printf("asf_read_pts\n");
url_fseek(&s->pb, pos + s->data_offset, SEEK_SET);
url_fseek(&s->pb, pos*asf->packet_size + s->data_offset, SEEK_SET);
asf_reset_header(s);
do{
if (av_read_frame(s, pkt) < 0){
@ -1369,7 +1360,9 @@ static int64_t asf_read_pts(AVFormatContext *s, int64_t *ppos, int stream_index)
av_free_packet(pkt);
}while(pkt->stream_index != stream_index || !(pkt->flags&PKT_FLAG_KEY));
asf_st= s->streams[stream_index]->priv_data;
*ppos= asf_st->packet_pos - s->data_offset;
assert((asf_st->packet_pos - s->data_offset) % asf->packet_size == 0);
*ppos= (asf_st->packet_pos - s->data_offset) / asf->packet_size;
//printf("found keyframe at %Ld stream %d stamp:%Ld\n", *ppos, stream_index, pts);
return pts;
@ -1391,7 +1384,7 @@ static int asf_read_seek(AVFormatContext *s, int stream_index, int64_t pts)
pts_min = asf_read_pts(s, &pos_min, stream_index);
if (pts_min == AV_NOPTS_VALUE) return -1;
pos_max = asf_align(s, url_filesize(url_fileno(&s->pb)) - 1 - s->data_offset); //FIXME wrong
pos_max = (url_filesize(url_fileno(&s->pb)) - 1 - s->data_offset) / asf->packet_size; //FIXME wrong
pts_max = pts_min + s->duration;
pos_limit= pos_max;
@ -1399,17 +1392,14 @@ static int asf_read_seek(AVFormatContext *s, int stream_index, int64_t pts)
int64_t start_pos;
assert(pos_limit <= pos_max);
assert(pos_limit % asf->packet_size == 0);
assert(pos_max % asf->packet_size == 0);
assert(pos_min % asf->packet_size == 0);
// interpolate position (better than dichotomy)
pos = (int64_t)((double)(pos_limit - pos_min) *
(double)(pts - pts_min) /
(double)(pts_max - pts_min)) + pos_min;
pos= asf_align(s, pos);
pos/= asf->packet_size;
if(pos <= pos_min)
pos= pos_min + asf->packet_size;
pos= pos_min + 1;
else if(pos > pos_limit)
pos= pos_limit;
start_pos= pos;
@ -1420,7 +1410,7 @@ static int asf_read_seek(AVFormatContext *s, int stream_index, int64_t pts)
if (cur_pts == AV_NOPTS_VALUE) {
return -1;
} else if (pts < cur_pts) {
pos_limit = start_pos - asf->packet_size;
pos_limit = start_pos - 1;
pos_max = pos;
pts_max = cur_pts;
} else {
@ -1432,7 +1422,7 @@ static int asf_read_seek(AVFormatContext *s, int stream_index, int64_t pts)
}
}
pos = pos_min;
url_fseek(&s->pb, pos + s->data_offset, SEEK_SET);
url_fseek(&s->pb, pos*asf->packet_size + s->data_offset, SEEK_SET);
asf_reset_header(s);
return 0;
}