Guessing from bitrate will provide adequate results in most cases.
---
We have this ugly thing in utils.c cargoculted from 2003 that tries to
seek before the end for mpeg and mpegts and guesses the duration from
the packets it finds there.
I think this kind of format-specific hacks isn't justified, so we should
get rid of it. Alternatively we could try to make this more generic or
move the code to mpeg/mpegts demuxers.
Opinions?
---
libavformat/utils.c | 96 +---------------------------------------------
tests/ref/seek/lavf_mpg | 2 +-
2 files changed, 4 insertions(+), 94 deletions(-)
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 6393b62..93f8be8 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -1929,91 +1929,7 @@ static void
estimate_timings_from_bit_rate(AVFormatContext *ic)
}
}
-#define DURATION_MAX_READ_SIZE 250000
-#define DURATION_MAX_RETRY 3
-
-/* only usable for MPEG-PS streams */
-static void estimate_timings_from_pts(AVFormatContext *ic, int64_t old_offset)
-{
- AVPacket pkt1, *pkt = &pkt1;
- AVStream *st;
- int read_size, i, ret;
- int64_t end_time;
- int64_t filesize, offset, duration;
- int retry=0;
-
- ic->cur_st = NULL;
-
- /* flush packet queue */
- flush_packet_queue(ic);
-
- for (i=0; i<ic->nb_streams; i++) {
- st = ic->streams[i];
- if (st->start_time == AV_NOPTS_VALUE && st->first_dts ==
AV_NOPTS_VALUE)
- av_log(st->codec, AV_LOG_WARNING, "start time is not set in
estimate_timings_from_pts\n");
-
- if (st->parser) {
- av_parser_close(st->parser);
- st->parser= NULL;
- av_free_packet(&st->cur_pkt);
- }
- }
-
- /* estimate the end time (duration) */
- /* XXX: may need to support wrapping */
- filesize = ic->pb ? avio_size(ic->pb) : 0;
- end_time = AV_NOPTS_VALUE;
- do{
- offset = filesize - (DURATION_MAX_READ_SIZE<<retry);
- if (offset < 0)
- offset = 0;
-
- avio_seek(ic->pb, offset, SEEK_SET);
- read_size = 0;
- for(;;) {
- if (read_size >= DURATION_MAX_READ_SIZE<<(FFMAX(retry-1,0)))
- break;
-
- do {
- ret = av_read_packet(ic, pkt);
- } while(ret == AVERROR(EAGAIN));
- if (ret != 0)
- break;
- read_size += pkt->size;
- st = ic->streams[pkt->stream_index];
- if (pkt->pts != AV_NOPTS_VALUE &&
- (st->start_time != AV_NOPTS_VALUE ||
- st->first_dts != AV_NOPTS_VALUE)) {
- duration = end_time = pkt->pts;
- if (st->start_time != AV_NOPTS_VALUE)
- duration -= st->start_time;
- else
- duration -= st->first_dts;
- if (duration < 0)
- duration += 1LL<<st->pts_wrap_bits;
- if (duration > 0) {
- if (st->duration == AV_NOPTS_VALUE || st->duration <
duration)
- st->duration = duration;
- }
- }
- av_free_packet(pkt);
- }
- }while( end_time==AV_NOPTS_VALUE
- && filesize > (DURATION_MAX_READ_SIZE<<retry)
- && ++retry <= DURATION_MAX_RETRY);
-
- fill_all_stream_timings(ic);
-
- avio_seek(ic->pb, old_offset, SEEK_SET);
- for (i=0; i<ic->nb_streams; i++) {
- st= ic->streams[i];
- st->cur_dts= st->first_dts;
- st->last_IP_pts = AV_NOPTS_VALUE;
- st->reference_dts = AV_NOPTS_VALUE;
- }
-}
-
-static void estimate_timings(AVFormatContext *ic, int64_t old_offset)
+static void estimate_timings(AVFormatContext *ic)
{
int64_t file_size;
@@ -2026,12 +1942,7 @@ static void estimate_timings(AVFormatContext *ic,
int64_t old_offset)
file_size = 0;
}
- if ((!strcmp(ic->iformat->name, "mpeg") ||
- !strcmp(ic->iformat->name, "mpegts")) &&
- file_size && ic->pb->seekable) {
- /* get accurate estimate from the PTSes */
- estimate_timings_from_pts(ic, old_offset);
- } else if (has_duration(ic)) {
+ if (has_duration(ic)) {
/* at least one component has timings - we use them for all
the components */
fill_all_stream_timings(ic);
@@ -2233,7 +2144,6 @@ int avformat_find_stream_info(AVFormatContext *ic,
AVDictionary **options)
int i, count, ret, read_size, j;
AVStream *st;
AVPacket pkt1, *pkt;
- int64_t old_offset = avio_tell(ic->pb);
int orig_nb_streams = ic->nb_streams; // new streams might appear,
no options for those
for(i=0;i<ic->nb_streams;i++) {
@@ -2479,7 +2389,7 @@ int avformat_find_stream_info(AVFormatContext *ic,
AVDictionary **options)
}
}
- estimate_timings(ic, old_offset);
+ estimate_timings(ic);
compute_chapters_end(ic);
diff --git a/tests/ref/seek/lavf_mpg b/tests/ref/seek/lavf_mpg
index dc51195..d037d9e 100644
--- a/tests/ref/seek/lavf_mpg
+++ b/tests/ref/seek/lavf_mpg
@@ -1,6 +1,6 @@
ret: 0 st: 1 flags:1 dts: 1.000000 pts: 1.000000 pos: 2048 size:
208
ret: 0 st:-1 flags:0 ts:-1.000000
-ret: 0 st: 1 flags:1 dts: 1.000000 pts: 1.000000 pos: 2048 size:
208
+ret: 0 st: 0 flags:0 dts: 1.000000 pts: 1.040000 pos: 26624 size:
16303
ret: 0 st:-1 flags:1 ts: 1.894167
ret: 0 st: 0 flags:0 dts: 1.880000 pts: 1.920000 pos: 327680 size:
12894
ret: 0 st: 0 flags:0 ts: 0.788333
--
1.7.6.3
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