[FFmpeg-devel] mpeg2ts/udp --> broken display by set-top-box

Måns Rullgård mans
Thu Jan 22 02:53:23 CET 2009

Baptiste Coudurier <baptiste.coudurier at gmail.com> writes:

> M?ns Rullg?rd wrote:
>> Baptiste Coudurier <baptiste.coudurier at gmail.com> writes:
>>> Hi,
>>> Alexandre FERRIEUX - FT/RD/SIRP/ASF/SOFTL wrote:
>>>> Hi,
>>>> I am now using ffmpeg to stream video to a set-top-box:
>>>> ./ffmpeg -i 134.wmv -vcodec mpeg2video -acodec mp2 -f mpegts 
>>>> udp://HOST:PORT\?pkt_size=1316
>>>> What I see on the TV is a sequence of chunks of correct video and
>>>>  (somewhat shorter) correct sound.
>>>> Of course I first thought about a problem in the bitstream or TS 
>>>> muxer, but... if I receive the same UDP flow and concatenate the 
>>>> contents in a .ts file, that file is played perfectly by 
>>>> mplayer/ffplay/vlc.
>>> Well, if the generated TS plays fine, this might indicate the TS is
>>>  somehow correct.
>> The TS playing on a PC means very little.
> This is not false, however it seems VLC cares about the PCR and screws
> the playback when something is wrong with it.

Nit: VLC screws up playback when *it* thinks something is wrong with
the PCR.

>> It could still be overflowing buffers on the STB.
> Yes, probably.

It could be worthwhile testing with a video-only stream.  This should
be much less sensitive to muxing irregularities.

M?ns Rullg?rd
mans at mansr.com

More information about the ffmpeg-devel mailing list