[NBLUG/talk] sox ulaw to mp3

[Bob Blick]

Hi Walter,

ulaw is different enough that I'm not surprised some apps don't 
understand it. You will probably need to do a sample rate conversion 
to something more typical as an intermediate step - also you will get 
the proper resolution since ulaw is compressed and you don't want it 
to be treated as raw even if you get the sample rate to match.

Cheerful regards,

Bob


On 27 Sep 2006 at 19:23, Walter Hansen wrote:

> I'm getting squirels.
> 
> I'm taking a ulaw 8000hz mono file and trying to make it into an mp3.
> It's going pretty good to wav.
> The wav reports 64kbps bitrate, 8bit audio sample, mono, 8khz sample rate
> and CCITT u-law audio format.
> 
> If I do it with lame at the command line it claims it's invalid. I'm
> assuming much the same is happening under covers when I invoke sox. And
> then I get a wav of chipmunks. I've tried lots of different options in
> lame with no better luck. I'm thinking that perhaps having sox put it into
> a format that lame will understand better might work best, but my attempts
> to date have failed. Are there any audio masters out there who know what's
> up? I couldn't use apt-get from debian for the mp3 stuff and ended up
> installing lame and sox from source. The wav files will work, but the
> slimer mp3 files will look better on a web server.
> 
> lame 376756.NAME.WAV test.mp3
> Warning: corrupt or unsupported WAVE format
> Assuming raw pcm input file
> LAME 3.97 64bits (http://www.mp3dev.org/)
> Using polyphase lowpass filter, transition band: 16538 Hz - 17071 Hz
> Encoding 376756.NAME.WAV to test.mp3
> Encoding as 44.1 kHz 128 kbps j-stereo MPEG-1 Layer III (11x) qval=3
>     Frame          |  CPU time/estim | REAL time/estim | play/CPU |    ETA
>     13/13    (100%)|    0:00/    0:00|    0:00/    0:00|   11.320x|    0:00
> ------------------------------------------------------------------------------------------------------------------------------------------------------------
>    kbps        MS  %     long switch short %
>   128.0      100.0        69.2  15.4  15.4
> Writing LAME Tag...done
> ReplayGain: -10.9dB