Re: [ecasound] Ecasound 2.4.4 released

From: Kai Vehmanen <kvehmanen@email-addr-hidden>
Date: Tue Jan 31 2006 - 01:59:40 EET


On Sat, 28 Jan 2006, Junichi Uekawa wrote:

> I don't remember since when, but recording from my USB audio
> (alsahw,2,0,0) and playing back on internal audio (IXP) seems to cause
> underruns. On the other hand, specifying the format with '-f
> 16,2,48000' to change it to 48000 seems to make it behave well.

as the two devices are driven by independent clock sources, they are bound
to go out of sync sooner or later (-> xruns). Using the 48000 srate might
help because it's probably the "native rate" of the internal audio chip
(very common nowadays), and is thus more accurate.

> $ ecasound -i alsahw,2,0,0 -o alsahw,0,0,0
> $ ecasound -f 16,2,48000 -i alsahw,2,0,0 -o alsahw,0,0,0

One way to decrease underruns is to add "-z:intbuf" (use all buffering
that the sound devices are capable of).

PS Alternatively, it's possible to write software that detects
    and corrects clock-drift in real-time. One example is the
    jack-diplomat project (run one JACK server for each device, and
    then run jack-diplomat to connect the two JACK systems).
    With some hardware you can sync multiple device via some
    external methods like word-clock cabling (or even something
    like ... )
    ... but I'd first try -f:16,2,48000 plus -z:intbuf and see how well
    it works.

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Received on Tue Jan 31 04:15:08 2006

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