[FFmpeg-devel] [PATCH] libavformat/mpegtsenc: improved cbr mode pcr accuracy

Michael Niedermayer michael at niedermayer.cc
Tue Jun 14 16:30:32 CEST 2016

On Tue, Jun 14, 2016 at 04:25:50PM +0300, Alexander Shumsky wrote:
> 08.06.2016 18:48, Michael Niedermayer пишет:
> >did you test this ?
> >if so please provide information & test results from it
> >
> >also has this been tested with multiple programs ?
> We have tested this with StreamGuru MPEG Analyzer. With default 20ms
> PCR interval patched version gives max PCR interval 21ms while with
> unpatched version max interval is 26ms (See screenshots).

The big problem of our TS muxer is the packet interleaving
the granularity of the interval is too big
This also results in the PCR being a bit unevenly spaced

The code should be changed to allow optional packet interleaving at
finer granularity to improve compliance of some high bitrate cases
If things can be interleaved with finer granularity then PCR too
can more easily be made more evenly spaced.

Please correct me if iam wrong but your patch basically makes an
exception to the (non optimal) interleaver for PCR only
Isnt this a hack on top of the current non optimal code?

also  MPEG-TS requires the interval to be < 100ms
(see 2.7.2 Frequency of coding the program clock reference)

both 21 and 26ms are within that


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have often repented speaking, but never of holding my tongue.
-- Xenocrates
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