Subject: Re: [linux-audio-user] why is my mp3 file bigger than my wav file?
From: Ross Vandegrift (ross_AT_willow.seitz.com)
Date: Sat Feb 02 2002 - 20:51:03 EET
> When I do the same commands with a stereo source, I get the kind of
> compression I expect:
>
> -rw-rw-r-- 1 lconrad lconrad 2461696 Feb 2 12:10 stoks.mp3
> -rw-r--r-- 1 lconrad root 27172908 Feb 2 10:24 stoks.wav
>
> I don't see why the mono recording would be lower quality than the
> stereo (once it gets to my sound card).
It has to do with various stereo modes of lame. It's no lower quality
necessarily, it's that lame is trying to correlate cross-channel data between a
mono wave on the left channel and a mono zero on the right channel.
You could deal with this using lame (this kinda belongs in my last mail, oh
well):
$ lame -a infile.wav outfile.mp3
will downmix to mono on the fly.
$ lame -m force infile.wav outfile.mp3
or
$ lame -m stereo infile.wav outfile.mp3
should tell lame not to use joint stereo mode (knowing that there is no
correleating between channels). You would use this if you actually want two
channel and one of them to be silent and not a mono wav.
Ross Vandegrift
ross_AT_willow.seitz.com
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