[alsa-devel] Noise Problem with rate convert plugins

Takashi Iwai tiwai at suse.de
Fri Jul 20 17:08:58 CEST 2007

At Mon, 16 Jul 2007 16:25:58 +0200,
Andreas Rumpler wrote:
> [1  <text/plain; ISO-8859-1 (7bit)>]
> Dear Takashi,
> Thanks for your response. I've tried the patch. It's seems be better 
> now. But something seems still to be wrong.
> At the start of the playback a short sequence seems to be outputed 
> twice. Please have a look at the attached screenshot from my oszi. The 
> screenshot shows playback of a sine with 440Hz.

Hm, it's weird.  I'll check this later.

> The length of the sequence outputed twice is different for every 
> samplerate conversion factor. If I go from 8kHz to 48kHz, it's 2.6 
> millisec long. If I go from 22.025kHz to 48kHz, it's 900 microsec long. 
> So it seems to be a fixed count of samples.

BTW, a temporary fix against the problem with speex resampler was
committed to HG tree today.  It'll always use the interpolation, thus
more CPU time, but it's still not that bad at all.  Give it a try.


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