Search found 59 matches

by robiwan
Mon Jul 24, 2017 4:30 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Audio injector zero kickstarter is live !
Replies: 22
Views: 7255

Re: Audio injector zero kickstarter is live !

Texas Instruments has a lot of codecs that support 192 kHz, Matt ;)
by robiwan
Sat Jul 22, 2017 7:42 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Audio injector zero kickstarter is live !
Replies: 22
Views: 7255

Re: Audio injector zero kickstarter is live !

Any preliminary date when this one will be available for purchase ? :)
by robiwan
Fri Jul 21, 2017 9:11 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20453

Re: Lowest possible latency

Actually, I now been able to run alsaloop with a latency of 48 frames @ 48 kHz, which means a total of 1ms SW latency. Awesome! I had to use chrt to heighten process to realtime status though. But now it works without a glitch, running the LADSPA reverb :) True, I might not have the time to write th...
by robiwan
Tue Jul 18, 2017 6:22 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20453

Re: Lowest possible latency

Well, if 64 is the latency, then it is pretty good. I'd definitely settle for < 1ms throughput latency. Anyway, I tried to setup an asymmetric alsa device, like so: /etc/asound.conf: pcm.ladspa { type ladspa slave.pcm "plughw:0" path "/usr/lib/ladspa" plugins [{ # Reverb plugin from the CAPS LADSPA ...
by robiwan
Mon Jul 17, 2017 6:51 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20453

Re: Lowest possible latency

The full duplex test, is it using a polling thread or an ALSA callback ?
by robiwan
Mon Jul 17, 2017 6:28 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20453

Re: Lowest possible latency

Got everything to compile, and running the full duplex test I cannot get below 64 frames. I get: latency = 0.000666667 s opening the device hw:0 opening the device hw:0 func: fillParams func: setAccess func: setFormat func: setChannels func: setSampleRate opening the device hw:0 opening the device h...
by robiwan
Sun Jul 16, 2017 3:34 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20453

Re: Lowest possible latency

Thanks! Having been experimenting around a bit, I've decided to put the DSP inside a LADSPA plugin, and use the ALSA LADSPA PCM plugin to load it, works nicely with f.i. Mopidy. The ALSA full duplex example is needed though to pipe from input to output, so the full pipeline would be: i2s_in -> alsa_...
by robiwan
Sun Jul 16, 2017 3:12 am
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20453

Re: Lowest possible latency

Using the patest_wire from Portaudio, and paFramesPerBufferUnspecified + PA_ALSA_PERIODSIZE = 32 I can get reliable streaming. With 24 it seems a bit shaky, but that might relate to the Portaudio ALSA implementation, still, that should be a latency of about (32 * 2)/48000 ~ 1.33 ms. I might be able ...
by robiwan
Sun Jul 16, 2017 2:23 am
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20453

Re: Lowest possible latency

NEVERMIND! The input mux was set for Mic. A little confusing having the input mux on the Playback page of alsamixer ;)
by robiwan
Sun Jul 16, 2017 1:30 am
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20453

Re: Lowest possible latency

Ok, I'm having a bit of a trouble, tried to record from the card, but I get nothing but silence: > arecord -L null Discard all samples (playback) or generate zero samples (capture) ladspa pladspa default:CARD=audioinjectorpi audioinjector-pi-soundcard, Default Audio Device sysdefault:CARD=audioinjec...