[Speex-dev] Preprocessor frame size

Троцкий Василий altersoft at mail.ru
Sat Sep 26 12:13:56 PDT 2009

I have a question about preprocessor frame_size.

I can read in libspeex API http://speex.org/docs/manual/speex-manual/node7.html
"It is recommended to use the same value for frame_size as is used by
the encoder (20 ms)."
But I have no enough RAM(in my embedded project) to bring up
preprocessor with 20ms frame size.
As I understand, it is possible to use smaller frame size, but it is not recommended. Why?
Can I use 32samples frame_size?
What about quality/side effects in this case?
Echo canceller seems to be OK with 32sample frame_size....
Echo canceller frame_size and preprocessor frame_size must be
equal(when using preprocessor residual echo supression)?

Another question: can I somehow reduce memory usage if I need only AGC
from preprocessor?

Thanks a lot! Speex is wonderful! :)

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