Re: [ecasound] Garbage at end of playback: ecasound or alsa broken?

From: Knut Petersen <>
Date: Sat Jul 20 2013 - 22:10:31 EEST

On 20.07.2013 20:02, Joel Roth wrote:
> Hi Knut,
> Knut, if you want a copy of testout.wav, I don't see why
> you are using the soundcard as an input, except maybe
> as a source for extra silence. If so, that may not
> be the best solution.

The RME Digi96 / PAD with expansion boards allows up to 8
channels of 24 bit audio for simultaneous recording and playback,
but the hardware buffer is small: 42.666 ms. So I modified the
kernel driver rme96.c to allow (much) bigger buffers to reliably prevent
buffer underruns / overruns.

The modified rme96.c does work perfectly with arecord, aplay, and a
number of other applications, but it breaks audacity as audacity does
fail to play correctly on non-mmap devices.

I also tested ecasound, and found the problem described in
the original post.

Recording the output and comparing input/output is simply a test
that can help to find the necessary multitrack offset but it is also
very helpful to validate the working of all the software layers involved.

  Knut Petersen

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Received on Sun Jul 21 08:15:02 2013

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