[PD] Shairport-sync Audio pipe into pure data

[IOhannes m zmoelnig]

On 2015-12-03 08:32, corentin THIERCELIN wrote:
> Hi,
> 
> I'm using shairport-sync on my Raspberry Pi to get audio from an Airplay source. Now I'd like to do signal processing on it, via a Pd patch, before its output to the speakers. 
> To do so, I tried to use jack with Pd but It's not working smoothly.

"not working smoothly"??
could you be more specific?

> So I looked for a more direct way of wiring shairport and Pure Data. I found that shairport allow the output to a raw audio pipe.  Is there any chance to capture this pipe into pure data ?

well, you could write an external that does that.
a naive approach should be easy enough, though i don't think that
anybody has done that.
also, "raw audio" is a *very* unspecific term, and the result might be
unsatisfactory if the producer and the consumer of that pipe don't agree.

another critical issue is timing: e.g. if your shairport source plays at
44100Hz but your Pd runs at 48kHz, the Pd process will starve of audio
samples (leading to drop-outs).
unfortunately this holds also true if both are running on a nominal SR
of 44.1kHz but they are not actually synching on the same
hardware-clock, then you get gltiches as well.

jack is the solution for all these problems.
so i would invest time in making the shairport/pd/jack combination to
"run smoothly" rather than doing an ad-hoc solution involving raw audio
pipes.

fgmasdr
IOhannes

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