[speex-dev] Speex test cases?

Jean-Marc Valin jean-marc.valin at hermes.usherb.ca
Mon Feb 10 22:29:20 PST 2003

> I don't have answers to 1 or 3, but on the issue of good test data, I've
> been doing a bunch of testing. My best source of test data is System Shock
> 2, the video game. It includes 177 MB (4.3 hours) of speech WAV files in
> 16kHz IMA ADPCM format by various types of voices (male, female, noisy,
> sharp, robotic, organic). Using a shell script and sox, I was able to
> compress it down to 17 MB using 16 kHz wideband, variable bit rate,
> quality 8 with release candidate 1. It definately isn't lossless, but
> it's very good. If you'd like a few of these wav files to test (100k-300k
> each), I can put a few on my web server.

Please don't do that. Tandeming should be avoided whenever possible and
it's simply not acceptable as testing conditions for a codec (unless you
explicitly want to test for tandeming quality). While not necessarily
perceptible, ADPCM will modify the spectral shape of the signal and will
likely make Speex (at least slightly) less efficient.


Jean-Marc Valin, M.Sc.A.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada

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