[CELT-dev] Issue with signals with lots of bass

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Sat Dec 6 19:18:47 PST 2008


We've just found an issue when encoding signals that have very powerful
bass (e.g. a loud 40 Hz tone). Turns out that was a combination of the
MDCT leakage with some inefficiency in the VQ search. There's a
tentative fix for that in git, which I'm encouraging everyone to test.
To enable the fix, look for these lines in alg_quant() (vq.c):

#if 0
   if (K > (N>>1))

Just replace with #if 1 and the fix will be enabled. I'm not yet 100%
sure it's safe, so please report and problem (or success). The good
thing is that this should not only solve the original, but it should
also reduce the CPU usage.



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