[MPlayer-users] Trouble with realtime transcoding

wwwadmin unkn0wn at megabit.ru
Fri Sep 14 09:23:52 CEST 2007


> On Thu, Sep 13, 2007 at 01:40:35PM +0400, wwwadmin wrote:
> > I try to transcode aac stream to mp3, but i have trouble: when
> > mplayer out sound to soundcard, all works fine, but when I try to
> > send raw-output to lame, encoding work with a jerks: mplayer
> > recieve some portion of a stream (~2sec) and freeze (~0.5sec), and
> > it's repeated and repeated. I use construction
> > "mplayer->lame->ezstream" to send encoded mp3 stream to icecast,
> > and in freeze time i listen noise. I try to use -cache and
> > -cache-min with no effect. Where is a bug?
> > 
> > Command line: 
> > mplayer -playlist /tmp/radio/drum.m3u -ac faad -demuxer aac -vc
> > null -vo null -cache 256 -cache-min 40 -ao
> > pcm:nowaveheader:file=/dev/stdout | lame --silent -q 0 -b 128 - - |
> > ezstream -c /usr/local/etc/ez_drum.xml
> 
> I assume that the cache you specify is big enough to permit a smoot
> playback. If not a stop is normal.
> 
> Apart from that, you can use the command line in this way in order to
> feed properly the raw audio stream to lame (requires bash or a bourne
> compatible shell):
> 
> mplayer <options> -vc null -vo null \
>   -ao pcm:nowaveheader:file=/dev/fd/4 4>&1 >&2 | lame <options> ....
> 
> For even faster decoding replace -vc null with -vc dummy.
> -vc dummy may not work all the times, but in this case it should.
> 
> Ciao
> Giacomo

I make mistake: mplayer cache 2 sec without out to lame, after caching
it write cache to stdout in lame input.

I try 32k-cache and zero cache-min with no effect. 

Situations:
- Playback. Mplayer precache stream, after this it decode aac and out
stream to soundcard on-the-fly, without jecks.
- Store wav. Mplayer cache stream, write to file, cache stream, write
to file,... Mplayer doesn't write stream at cache-time, it's a problem.



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