[MPlayer-users] Audio encoding speed?

Josef Wolf jw at raven.inka.de
Mon Jan 24 18:05:05 CET 2005


On Sun, Jan 23, 2005 at 08:54:37PM +0300, Phil Oleynik wrote:
> Josef Wolf wrote:

> >I noticed that encoding mpeg2 TS streams to divx with 
> >
> > mencoder -ni -cache 4096 in.vdr -o out.avi \
> >   -ovc lavc -lavcopts vcodec=mpeg4:vqmin=2:mbd=0:vpass=1 \
> >   -oac mp3lame -lameopts q=0:vbr=0:aq=0
> >
> >takes about four times longer than with
> >
> > mencoder -ni -cache 4096 in.vdr -o out.avi \
> >   -ovc lavc -lavcopts vcodec=mpeg4:vqmin=2:mbd=0:vpass=1 \
> >   -oac copy
> >
> >This would mean that audio encoding takes about three times longer than
> >video encoding.
>
> Try to encode some sound with lame standalone - to see where is the BUG
> lies.

Hmm, I tried:

   mplayer -dumpaudio blah.vdr

which results in a 154MB file (Indiana Jones, broadcasted yesterday over
Astra on german pro7 channel).  But this file seems not to be a valid
audio stream.  When I try to encode this file with lame, I get a mp3 file
with only noise :-(  How do I properly dump the audio stream that I can
encode it with standalone lame?

This is what mplayer says when I try to play without the -dumpaudio
option (shortened to audio relevant output):

==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
MP3lib: init layer2&3 finished, tables done
AUDIO: 48000 Hz, 2 ch, 16 bit (0x10), ratio: 24000->192000 (192,0 kbit)
Selected audio codec: [mp3] afm:mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
Checking audio filter chain for 48000Hz/2ch/16bit -> 48000Hz/2ch/16bit...
AF_pre: af format: 2 bps, 2 ch, 48000 hz, little endian signed int
AF_pre: 48000Hz 2ch Signed 16-bit (Little-Endian)
AO: [oss] 48000Hz 2ch Signed 16-bit (Little-Endian) (2 bps)
Building audio filter chain for 48000Hz/2ch/16bit -> 48000Hz/2ch/16bit...
Starting playback...

-- 
No software patents!
-- Josef Wolf -- jw at raven.inka.de --




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