On Fri, 3 Jan 2020 15:38:15 +0100, "R.Wieser" 
declaimed the following:

>Its just that I have zero idea why the sound gets cut short, even though
>inserting a seconds long usleep( ) just before the snd_pcm_drain( ) call
>shows that the whole length of sound is there.

 This description is very perplexing to me...

 A usleep() before the snd_pcm_drain() implies that the OS is during
something BEFORE you invoke the snd_pcm_drain() call. So focusing on that
call is a red-herring. It indicates, to me, that some call before the
usleep() needs to be investigated.

 Something like an asynchronous buffering operation which is returning
before the entire buffer has been transferred, and your subsequent
operations are interrupting/terminating the remaining transfer.

Just some random Google results...
https://github.com/raspberrypi/linux/issues/999
https://stackoverflow.com/questions/18034132/alsa-snd-pcm-drainhandle-the-strea
m-isnt-played-to-the-end


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