In article ,
Richard
Robinson wrote:

The DAC has a little row of lights showing the incoming sample rate. I
just set something playing and had a look ... none of them are lit up.
Helpful, no ? :-/

Afraid I've forgotten what kind of DAC you're using, so can only guess.

However it is possible that the DAC is fussy about the rate. So if the
playout is running too fast or too slow (or is too erratic) the LED doesn't
light up.

You can read a 'file' for each device and - when audio is playing - the
relevant one will state the rate, etc, being sent out to hardware. My
memory being what it is I can't immediately recall the 'file' names for
this. But if no-one else can say I'll find out and let you know later on.
[ Edit: see below :-) ]

If you're using -aplay you can use this to probe what works

get a list of devices from 'aplay -l'

then try 'aplay -D hw:one of them file.wav' to see if that will
play the file and give you a coconut. Using 'hw:' tells -aplay
to *not* provide any conversions. So it will only play when the
device can accept the rate and bit-depth of the wave file.

You can use sox to generate versions of a wave file with various
rates and bit depths.


Edit: Found how to check the output in my notebooks

look at files like /proc/asound/cardn/pcmmp/subp/hw_params

and cat their content to see what they hold *while you play
some audio*. Each file will report what's happening for a given
card, etc. If you hear music, the relevant one will report the
rate that is being used.

Jim

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