Re: ecasound+jack silent stop, silent data loss

Hi,

sorry for the (probably too) late response.

On Wed, 6 Dec 2006, Paul Knowles wrote:

>>> first thing that comes to my mind is a glitch in JACK
>>> transport support.  There're some messages about seeking in
>>> the middle of recording, and this shouldn't be
>>> happening. Could you retry the tests with adding the option
>>> "-G:jack,eca,notransport"...?
>>
>> This seems to have done the trick. At least I have now 12
>> hours of uninterrupted recording.  The analysis for phase
>> jumps (lost samples) is currently underway.
>
> Nope, spoke too soon.  After analysis, the data loss is
> still there,  It seems to be only one sample at most, not a
> whole buffer.  With the notransport option, ecasound just
> doesn't tell me about it.

You could try recording directly with ecasound+ALSA, i.e. without JACK. It 
shouldn't make any difference, but you'd have one less moving part in the 
puzzle. Missing a single sample does suggest a hardware/driver level 
problem though.

> I did isolate a problem with the word clock: while in use,
> occassionally the sound cards would drop the PLL coherence
> momentarily.  I could not correlate that to the loss of
> data, but when the PLL problem was made worse, there was no
> increase in (supposedly lost) sample corruption, so I don't
> think that the word clock is the problem there.
>
> Any hints on how to make ecasound exit when this seek event
> occurs?

I'm afraid this is a similar hw/driver level issue that is not 
escalated/signaled to application layer (i.e. to apps using 
alsa-lib/libasound). Recording directly from ALSA, and with '-z:xruns' 
ecasound option, might be worth a try though.

--

-- 
  links, my public keys, etc at http://eca.cx/kv

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