| Message ID | 4D821620.4050006@gmail.com |
|---|---|
| State | Committed |
| Headers | show |
Vladimir Pantelic <vladoman@gmail.com> writes: > Måns Rullgård wrote: >> Vladimir Pantelic<vladoman@gmail.com> writes: >> >>> Vladimir Pantelic wrote: >>>> Måns Rullgård wrote: >>>>> Vladimir Pantelic<vladoman@gmail.com> writes: >>>> >>>>>> So, maybe using preroll as start_time is bad, but so is not doing it >>>>>> as we can see above. I tend to rather follow the spec. >>>>> >>>>> The alternative would be to subtract the preroll value from all >>>>> timestamps in the demuxer and add it back in the muxer. Your patch >>>>> seems much simpler. >>>> >>>> Reading the spec again, I think we should rather subtract the preroll >>>> in the demuxer: >>>> >>>> "...player software *must* subtract the value in the preroll field >>>> from the play duration and presentation times to calculate their >>>> actual values..." >>> >>> now I set st->start_time to 0 and subtract the preroll, this way we >>> output 0 based timestamps and prevent ffmpeg.c from guessing the wrong >>> timestamps. >>> >>> From 1c72c47cec36d6548db0f9a622dc2430e5d5bd93 Mon Sep 17 00:00:00 2001 >>> From: Vladimir Pantelic<vladoman@gmail.com> >>> Date: Thu, 17 Mar 2011 14:56:14 +0100 >>> Subject: [PATCH] make ASF demuxer subtract the preroll value and thus output 0 based timestamps >>> >>> --- >>> libavformat/asfdec.c | 3 ++- >>> 1 files changed, 2 insertions(+), 1 deletions(-) >>> >>> diff --git a/libavformat/asfdec.c b/libavformat/asfdec.c >>> index cbcd576..3d68527 100644 >>> --- a/libavformat/asfdec.c >>> +++ b/libavformat/asfdec.c >>> @@ -236,6 +236,7 @@ static int asf_read_stream_properties(AVFormatContext *s, int64_t size) >>> if (!asf_st) >>> return AVERROR(ENOMEM); >>> st->priv_data = asf_st; >>> + st->start_time = 0; >>> start_time = asf->hdr.preroll; >>> >>> asf_st->stream_language_index = 128; // invalid stream index means no language info >>> @@ -960,7 +961,7 @@ static int ff_asf_parse_packet(AVFormatContext *s, AVIOContext *pb, AVPacket *pk >>> /* new packet */ >>> av_new_packet(&asf_st->pkt, asf->packet_obj_size); >>> asf_st->seq = asf->packet_seq; >>> - asf_st->pkt.dts = asf->packet_frag_timestamp; >>> + asf_st->pkt.dts = asf->packet_frag_timestamp - asf->hdr.preroll; >>> asf_st->pkt.stream_index = asf->stream_index; >>> asf_st->pkt.pos = >>> asf_st->packet_pos= asf->packet_pos; >> >> No PTS? > > asf has only DTS > >> The silly note about ASF in the start_time doxy should still go away. > > done > > > From e734562dded073e36f83534c2e504805c07abcd6 Mon Sep 17 00:00:00 2001 > From: Vladimir Pantelic <vladoman@gmail.com> > Date: Thu, 17 Mar 2011 14:56:14 +0100 > Subject: [PATCH] make ASF demuxer subtract the preroll value and thus output 0 based timestamps > > --- > libavformat/asfdec.c | 3 ++- > libavformat/avformat.h | 2 -- > 2 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/libavformat/asfdec.c b/libavformat/asfdec.c > index cbcd576..3d68527 100644 > --- a/libavformat/asfdec.c > +++ b/libavformat/asfdec.c > @@ -236,6 +236,7 @@ static int asf_read_stream_properties(AVFormatContext *s, int64_t size) > if (!asf_st) > return AVERROR(ENOMEM); > st->priv_data = asf_st; > + st->start_time = 0; > start_time = asf->hdr.preroll; > > asf_st->stream_language_index = 128; // invalid stream index means no language info > @@ -960,7 +961,7 @@ static int ff_asf_parse_packet(AVFormatContext *s, AVIOContext *pb, AVPacket *pk > /* new packet */ > av_new_packet(&asf_st->pkt, asf->packet_obj_size); > asf_st->seq = asf->packet_seq; > - asf_st->pkt.dts = asf->packet_frag_timestamp; > + asf_st->pkt.dts = asf->packet_frag_timestamp - asf->hdr.preroll; > asf_st->pkt.stream_index = asf->stream_index; > asf_st->pkt.pos = > asf_st->packet_pos= asf->packet_pos; > diff --git a/libavformat/avformat.h b/libavformat/avformat.h > index ce50053..ca179d2 100644 > --- a/libavformat/avformat.h > +++ b/libavformat/avformat.h > @@ -534,8 +534,6 @@ typedef struct AVStream { > * Only set this if you are absolutely 100% sure that the value you set > * it to really is the pts of the first frame. > * This may be undefined (AV_NOPTS_VALUE). > - * @note The ASF header does NOT contain a correct start_time the ASF > - * demuxer must NOT set this. > */ > int64_t start_time; > > -- > 1.6.0.2 Looks fine. Queued, will push later.
From e734562dded073e36f83534c2e504805c07abcd6 Mon Sep 17 00:00:00 2001 From: Vladimir Pantelic <vladoman@gmail.com> Date: Thu, 17 Mar 2011 14:56:14 +0100 Subject: [PATCH] make ASF demuxer subtract the preroll value and thus output 0 based timestamps --- libavformat/asfdec.c | 3 ++- libavformat/avformat.h | 2 -- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/libavformat/asfdec.c b/libavformat/asfdec.c index cbcd576..3d68527 100644 --- a/libavformat/asfdec.c +++ b/libavformat/asfdec.c @@ -236,6 +236,7 @@ static int asf_read_stream_properties(AVFormatContext *s, int64_t size) if (!asf_st) return AVERROR(ENOMEM); st->priv_data = asf_st; + st->start_time = 0; start_time = asf->hdr.preroll; asf_st->stream_language_index = 128; // invalid stream index means no language info @@ -960,7 +961,7 @@ static int ff_asf_parse_packet(AVFormatContext *s, AVIOContext *pb, AVPacket *pk /* new packet */ av_new_packet(&asf_st->pkt, asf->packet_obj_size); asf_st->seq = asf->packet_seq; - asf_st->pkt.dts = asf->packet_frag_timestamp; + asf_st->pkt.dts = asf->packet_frag_timestamp - asf->hdr.preroll; asf_st->pkt.stream_index = asf->stream_index; asf_st->pkt.pos = asf_st->packet_pos= asf->packet_pos; diff --git a/libavformat/avformat.h b/libavformat/avformat.h index ce50053..ca179d2 100644 --- a/libavformat/avformat.h +++ b/libavformat/avformat.h @@ -534,8 +534,6 @@ typedef struct AVStream { * Only set this if you are absolutely 100% sure that the value you set * it to really is the pts of the first frame. * This may be undefined (AV_NOPTS_VALUE). - * @note The ASF header does NOT contain a correct start_time the ASF - * demuxer must NOT set this. */ int64_t start_time; -- 1.6.0.2