[FFmpeg-devel] [PATCH v2 2/3] avformat/mpegtsenc: make first_pcr sync with the first valid dts
lance.lmwang at gmail.com
lance.lmwang at gmail.com
Sun Oct 25 14:55:38 EET 2020
On Sun, Oct 25, 2020 at 01:04:11PM +0100, Marton Balint wrote:
>
>
> On Thu, 22 Oct 2020, lance.lmwang at gmail.com wrote:
>
> > From: Limin Wang <lance.lmwang at gmail.com>
> >
> > now first_pts assume dts will start from zero, if it's not true(copyts is enable),
> > too many null packet will be inserted for cbr output.
> >
> > Please test with below command, you'll get huge test.ts without the patch:
> > ./ffmpeg -y -copyts -i ../fate-suite/mpegts/loewe.ts -c:v libx264 -x264opts \
> > nal-hrd=cbr:force-cfr=1 -b:v 3500k -minrate 3500k -maxrate 3500k -bufsize \
> > 1000k -c:a mp2 -muxrate 4500k -vframes 1000 test.ts
> >
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> > libavformat/mpegtsenc.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
> > index 5c97d63..415a64e 100644
> > --- a/libavformat/mpegtsenc.c
> > +++ b/libavformat/mpegtsenc.c
> > @@ -81,6 +81,7 @@ typedef struct MpegTSWrite {
> > int64_t pat_period; /* PAT/PMT period in PCR time base */
> > int nb_services;
> > int64_t first_pcr;
> > + int first_dts_check;
>
> It is minor nitpicking, but can you rename this to first_dts_checked and
> reverse the logic? So this can be 0 by default (so it does not have to be
> explicitly initialized), and you set it to 1 after it is checked.
I'm OK for your suggestion for the name, but MpegTSWriteStream have defined a
first_pts_check for every stream to check first pts for stream, do you think
it's necessary to keep the same style?
>
> Thanks,
> Marton
>
> > int64_t next_pcr;
> > int mux_rate; ///< set to 1 when VBR
> > int pes_payload_size;
> > @@ -1134,6 +1135,7 @@ static int mpegts_init(AVFormatContext *s)
> >
> > if (ts->copyts < 1)
> > ts->first_pcr = av_rescale(s->max_delay, PCR_TIME_BASE, AV_TIME_BASE);
> > + ts->first_dts_check = 1;
> >
> > select_pcr_streams(s);
> >
> > @@ -1688,6 +1690,11 @@ static int mpegts_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
> > stream_id = side_data[0];
> >
> > if (ts->copyts < 1) {
> > + if (ts->first_dts_check && dts != AV_NOPTS_VALUE) {
> > + ts->first_pcr += dts * 300;
> > + ts->first_dts_check = 0;
> > + }
> > +
> > if (pts != AV_NOPTS_VALUE)
> > pts += delay;
> > if (dts != AV_NOPTS_VALUE)
> > --
> > 1.8.3.1
> >
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--
Thanks,
Limin Wang
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