>> 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?
In fact It's not working at all, the raspberry crashes. Because when using jack, I need to have shairport, pd and jack running together. And there is another step between shairport and jack : the loopback device. So that makes something like this : Shairport --> alsa loopback --> jack --> Pd --> jack --> alsa audio card. (you'll notice that I'm not able to choose an alsa output device when jack is set as input device in Pd) That may be too much for a Raspberry Pi ? I also tried to process like this : shairport --> loopback --> Pd --> audio card. Here I have sth inaudible! It sounds like the sample rate of the loopback is 1 Hz... And like this : shairport --> pipe --> loopback --> Pd --> audio card. Here, as you said, they are not synched, It sounds bad and the alsa command to catch the pipe indicates a lot of audio drops. So, these two cases are not good choices, for sure. > well, you could write an external that does 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. I wish I could write an external. I'm not comfortable with c code, that's exactly why I'm using Pd :) But I'll give a look at how to do this. Maybe I can get inspired by the alsa 'pipe reading' function ? The aplay command for listening to the audio pipe (directly to audio card) works perfectly, so, I'm telling myself : why not when reading directly the pipe within Pd ?! I need to test this way, that sounds more direct and more efficient ... Thanks for all your piece of advices. Corentoulf _______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
