Commit 38376f00 authored by Kevin Kuphal's avatar Kevin Kuphal Committed by Michael Niedermayer
Browse files

seeking in single stream asf patch by ("Kevin Kuphal" <kevin dot kuphal at sitecity dot net>)

Originally committed as revision 2700 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 237da0fa
......@@ -1225,6 +1225,8 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
asf_st->seq = asf->packet_seq;
asf_st->pkt.pts = asf->packet_frag_timestamp - asf->hdr.preroll;
asf_st->pkt.stream_index = asf->stream_index;
if (s->streams[asf->stream_index]->codec.codec_type == CODEC_TYPE_AUDIO)
asf->packet_key_frame = 1;
if (asf->packet_key_frame)
asf_st->pkt.flags |= PKT_FLAG_KEY;
}
......@@ -1286,20 +1288,136 @@ static int asf_read_close(AVFormatContext *s)
return 0;
}
// Added to support seeking after packets have been read
// If information is not reset, read_packet fails due to
// leftover information from previous reads
static void asf_reset_header(AVFormatContext *s)
{
ASFContext *asf = s->priv_data;
asf->packet_nb_frames = 0;
asf->packet_timestamp_start = -1;
asf->packet_timestamp_end = -1;
asf->packet_size_left = 0;
asf->packet_segments = 0;
asf->packet_flags = 0;
asf->packet_property = 0;
asf->packet_timestamp = 0;
asf->packet_segsizetype = 0;
asf->packet_segments = 0;
asf->packet_seq = 0;
asf->packet_replic_size = 0;
asf->packet_key_frame = 0;
asf->packet_padsize = 0;
asf->packet_frag_offset = 0;
asf->packet_frag_size = 0;
asf->packet_frag_timestamp = 0;
asf->packet_multi_size = 0;
asf->packet_obj_size = 0;
asf->packet_time_delta = 0;
asf->packet_time_start = 0;
}
static int64_t asf_read_pts(AVFormatContext *s, int64_t pos)
{
ASFContext *asf = s->priv_data;
AVPacket pkt1, *pkt = &pkt1;
int64_t seek_pos;
// ensure we are on the byte boundry
if (pos > asf->packet_size)
seek_pos = s->data_offset + ((pos / asf->packet_size) * asf->packet_size);
else seek_pos = pos;
url_fseek(&s->pb, seek_pos, SEEK_SET);
asf_reset_header(s);
if (av_read_frame(s, pkt) < 0)
return AV_NOPTS_VALUE;
return pkt->pts;
}
static int asf_read_seek(AVFormatContext *s, int stream_index, int64_t pts)
{
#if 0
ASFContext *asf = s->priv_data;
int i;
AVStream *st;
AVPacket pkt1, *pkt;
int block_align, byte_rate;
int64_t pos;
int64_t pos_min, pos_max, pts_min, pts_max, cur_pts;
for(i = 0;; i++) {
url_fseek(&s->pb, asf->data_offset + i * asf->packet_size, SEEK_SET);
if (asf_get_packet(s) < 0)
break;
printf("timestamp=%0.3f\n", asf->packet_timestamp / 1000.0);
pkt = &pkt1;
// Currently we only support single stream files like WMA
if (s->nb_streams > 1) return -1;
// Validate pts
if (pts < 0)
pts = 0;
// Acquire the specified stream
// If no stream is specified, use the only one we work with
if (stream_index == -1)
st = s->streams[0];
else st = s->streams[stream_index];
// ASF files have fixed block sizes, store this to determine offset
block_align = asf->packet_size;
byte_rate = st->codec.bit_rate / 8;
if (block_align <= 0 || byte_rate <= 0)
return -1;
pos_min = 0;
pts_min = asf_read_pts(s, s->data_offset);
if (pts_min == AV_NOPTS_VALUE) return -1;
pos_max = url_filesize(url_fileno(&s->pb)) - 1;
pts_max = pts_min + s->duration;
while (pos_min <= pos_max) {
if (pts <= pts_min) {
pos = pos_min;
goto found;
} else if (pts >= pts_max) {
pos = pos_max;
goto found;
} else {
// interpolate position (better than dichotomy)
pos = (int64_t)((double)(pos_max - pos_min) *
(double)(pts - pts_min) /
(double)(pts_max - pts_min)) + pos_min;
}
// read the next timestamp
cur_pts = asf_read_pts(s, pos);
/* check if we are lucky */
if (pts == cur_pts) {
goto found;
} else if (cur_pts == AV_NOPTS_VALUE) {
return -1;
} else if (pts < cur_pts) {
pos_max = pos;
pts_max = asf_read_pts(s, pos_max);
if (pts >= pts_max) {
pos = pos_max;
goto found;
}
} else {
pos_min = pos + asf->packet_size;
pts_min = asf_read_pts(s, pos_min);
if (pts <= pts_min) {
goto found;
}
}
}
#endif
return -1;
pos = pos_min;
found:
pos = s->data_offset + ((pos / block_align) * block_align);
url_fseek(&s->pb, pos, SEEK_SET);
asf_reset_header(s);
return 0;
}
static AVInputFormat asf_iformat = {
......
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