[LAU] How to decode raw ADPCM data?

Jozef Henzl popcorp86 at gmail.com
Wed Mar 12 05:43:23 EDT 2008


Hello,
Does anyone know which tool or library i can use to decode audio data stored 
in a ADPCM header-less file? (8kHz, 1 channel, (12,16,25 or 32) bit)
I've tried sox and libsamplerate, but both throws an error.

The data are from a voice-recording machine, with very limited documentation. 
It says the data are "standard ADPCM". No idea whether it is IMA or VOX or MS 
ADPCM format.

$ sox  -i -t raw -r8000 -2 -c1   data.adpcm -t wav out.wav                                 
sox sox: data.adpcm: this encoding is not supported for this data size 
(Unsupported data format)

and with sndfile:
<code snip>
sfinfo.format = SF_FORMAT_IMA_ADPCM | SF_FORMAT_RAW;
sfinfo.samplerate = 8000;
sfinfo.channels = 1;
if ((fpr = sf_open ("data.adpcm", SFM_READ, &sfinfo)) == NULL) 
...
</code snip>

thanks,
-- 
Jozef Henzl
http://popcorp.org
http://chan.cz



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