[Ffmpeg-devel] -ab 128 doesn't work with aac encoding?

Patrice Bensoussan patrice.bensoussan
Fri Aug 26 01:49:55 CEST 2005


I'm trying to convert a WMA file to AAC 128kbit, but it seems the -ab  
doesn't work : when I use -ab 128, the created file is 94kbit  
according to quicktime 7 :
Any idea what is happening? (i'm using the lastest ffmpeg cvs)

./ffmpeg -ab 128 -i blacksmith.wma backsmith.m4a
ffmpeg version CVS, build 3211266, Copyright (c) 2000-2004 Fabrice  
   configuration:  --enable-mp3lame --enable-faac --enable-small
   built on Aug 24 2005 20:02:45, gcc: 3.3 20030304 (Apple Computer,  
Inc. build 1809)
Input #0, asf, from 'blacksmith.wma':
   Duration: 00:00:31.9, start: 2.600000, bitrate: 175 kb/s
   Stream #0.0: Audio: wmav2, 44100 Hz, stereo, 160 kb/s
Output #0, mp4, to 'backsmith.m4a':
   Stream #0.0: Audio: aac, 44100 Hz, stereo, 128 kb/s
Stream mapping:
   Stream #0.0 -> #0.0
Press [q] to stop encoding
size=     405kB time=34.0 bitrate=  97.7kbits/s
video:0kB audio:393kB global headers:0kB muxing overhead 3.066695%

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