[MPlayer-users] Audio encoding speed?

[Jack]

Josef Wolf wrote:

>On Mon, Jan 24, 2005 at 12:16:08PM -0500, Piszcz, Justin Michael wrote:
>
>  
>
>>mplayer -vo null -vc dummy -ao pcm file.mpg
>>the output will be called audiodump.wav
>>    
>>
>
>Ah, OK.  This gives me a file of 1.2GB length.  Strange, the original
>video+audio is only 2.6GB (The movie is about 1:45 length).
>  
>
Because this is the uncompressed version.

>So here are the results:
>
>  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             # about 5 hours
>
>  
>
q=0 is pointless, because vbr=0 sets it to CBR mode.

>  lame -V 0 audiodump.wav foo.mp3                    # 30 minutes
>
>Sum: 1:37 hours
>---------------
>
>So obviously, about 3.5 hours are lost somewhere.  Any ideas what I can
>do next to find the cause why the 3.5 hours are lost?
>
>  
>
aq=0.

>PS: I can not find an equivalent to the aq=0 option in lame's options.
>    What does this aq=0 mean?
>
>  
>
It is equal to -q 0 on the lame command line.

>BTW: I noticed that the dumped mp2 file is even shorter than the
>     resulting mp3 file (154MB vs. 166MB).  So I wondered whether it is
>     really worth to reencode the audio. 
>
No, no it isn't worth it.  Reencoding like this would be totally 
pointless, and just lose more quality.  If you gain some space by 
reencoding to VBR or to a lower bitrate, that would be worth it.  The 
rest of that discussion really belongs on a lame list, I suppose.

... your lame options are totally inconsistent.  Are you trying to use 
VBR or CBR?  You keep switching. 

The equivalent lame command line to your -lameopts q=0:vbr=0:aq=0 would 
be lame -q 0  (cbr is default, and q=0 does nothing, as I pointed out 
above)

-jack