[FFmpeg-devel] [BUG] PCR, PTS drift for mpegts streams. Black screen on set-top box.
Olof Astrand
olof_astrand
Thu Jun 4 20:11:04 CEST 2009
> > PCR is related to DTS, and yes this is a known problem. It should work
> > better in CBR mode, ie with rc_max_rate set and respected.
>
> Baptiste, can you please give the explicit command-line switches and
> values to use for the CBR mode ?
>
> Also, an IP box is not likely to expect the stuffing used to reach the
> constant bitrate, so it might not fully work, right ?
>
> FWIW, here in my company, this very problem makes us dependent on vlc
> for TS muxing, which induces extra latency and instability (vlc has bugs
> too, though fewer in the TS muxer :-P ). So it is THE dark spot about
> ffmpeg which is absolutely perfect otherwise.
>
This works for us, however It is not CBR at all. Some set top boxes does not like it.
/usr/local/bin/ffmpeg -v 0 -f jack -ac 2 -i ffmpeg -ab 128000 -ac 2
-ar 44100 -acodec mp2 -f x11grab -r 25 -s pal -i :1.0 -vcodec
mpeg2video -b 8000000 -maxrate 12000000 -minrate 0 -bf 2 -i_qoffset 1
-bufsize 1835008 -packetsize 2048 -qscale 1 -threads 4 -f vob - | cvlc
--quiet --rc-fake-tty stream:///dev/stdin --sout
#std{access=udp,mux=ts,dst=239.255.148.69:5555} :ttl=8 2>&1 >
/dev/null &
Maybe the problem is that vlc works for TS muxing.
If it did not work then maybe someone would have more incentive to fix the it.
/Olof
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