[Gta04-owner] Sound playback

[Dr. H. Nikolaus Schaller]

Hi Neil,
that is an interesting thing I have never noticed. But the hw-test only plays one file…
(see hw-test script).

A very important piece of information is: which kernel and which distro do you use?

BR,
Nikolaus


Am 21.06.2014 um 01:17 schrieb Neil Jerram <neil at ossau.homelinux.net>:

> In my continuing mission to re-understand things that everyone else
> probably understood ages ago... :-)
> 
> I've noticed on my GTA04, with a plain ALSA setup, that sound playback
> sometimes works and sometimes doesn't.  For example, if I do:
> 
> root at neo:~# for n in `seq 1 5`; do aplay -D hw:0 -f S16_LE -c 1 test.wav; done
> 
> the stdout looks good:
> 
> Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Stereo
> Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Stereo
> Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Stereo
> Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Stereo
> Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Stereo
> 
> but I only hear the content of 'test.wav' 2 or 3 times out of 5.
> 
> If I do the same test again, still only 2 or 3 times out of 5, but in a
> different pattern.  (E.g. just now: #1 ok, #2 silence, #3 ok, #4
> silence, #5 ok.)
> 
> If I set the ALSA controls for playback through the earpiece, and listen
> very closely to individual playback attempts, some more observations:
> 
> 1. I can clearly hear two levels of 'silence' after the end of a
> successful playback.  There's a slight click that I assume marks the end
> of the .wav file, then around 5 seconds of low volume white noise, then
> a sudden drop to much better silence.

I think there is some timeout to suspend the hardware.

> 
> 2. During an unsuccessful playback I can hear some very faint noises,
> with a relative volume pattern roughly like the message that I should be
> hearing properly.
> 
> 3. It doesn't seem to make any difference, to whether the next playback
> will be successful or not, if I wait longer before starting it.
> 
> Does anyone have any ideas about:
> 
> - how I can understand what is happening here?
> 
> - if there is any practical thing / workaround I can do to guarantee
>  that the following playback attempt will be successful?
> 
> Many thanks,
> 
>     Neil
> 
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