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

Alexandre FERRIEUX - FT/RD/SIRP/ASF/SOFTL alexandre.ferrieux
Thu Jan 22 09:42:54 CET 2009

Hi Baptiste,

Baptiste Coudurier wrote:
> 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 problem is the Muchhausen effect: FFmpeg codecs are both on the 
sending and receiving sides since all three players decode with it :-}

What I forgot to add in the first message is that a vlc --sout 
"#transcode{vcodec=mp2v,venc=ffmpeg}:std{...,mux=ts}" displays perfectly 
on the same STB. So the difference lies somewehere in the (different) TS 
muxers of ffmpeg and vlc...

> Did you try adding "-re" in the commandline ?

Sorry, of course I use -re, I just pasted the line by pieces and forgot 
that one :-}.


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