________________________________ From: katja katjavetter@gmail.com To: Jonathan Wilkes jancsika@yahoo.com Cc: IOhannes m zmoelnig zmoelnig@iem.at; pddev pd-dev@iem.at Sent: Monday, June 3, 2013 6:23 PM Subject: Re: [PD-dev] jack dbus?
On Mon, Jun 3, 2013 at 9:25 PM, Jonathan Wilkes jancsika@yahoo.com wrote:
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Don't we want to compare straight to ALSA to pd to JACK to ALSA, just with Pd running? Having Pulse in the mix is good to measure as well, but I'd like to get a handle on the "JACK adds no latency" statement and comparing additionally with just Pd running through JACK will simplify that.
Also, it may be helpful to add: Pd through JACK, VLC using JACK backend through Jack and compare it to the one using PulseAudio through JACK.
If I'm not mistaken, it was your original idea
to test a setup where
all audio sources can be played together with Pd, i.e. Pd + PulseAudio
- JACK, and compare with Pd's current default routing (plain ALSA). So
that's what I did. I'm now eager to know results from others before further delving into it.
Sorry, I'm talking about a few things at once. One would be to test Pd by itself with ALSA backend vs. Pd by itself with JACK backend. That would provide some data re: the page you linked to about latency. (My suggestion about Pd->JACK + VLC-with-jack-backend->JACK was meant to cover that case and also compare to Pd->JACK +Pulse->JACK, but as you say we can delve into that later.)
The other is: what's a "recommendable" setup for using Pd in GNU/Linux with acceptable/controllable latency while still behaving with the rest of the system. Your Pd/Pulse/JACK measurements help to address that.
So [when I find my cord] I'll give results for: Pd by itself directly to ALSA Pd by itself through JACK (with qjackctl, and with ALSA as JACK's backend) Pd to JACK + "other stuff" through Pulse to JACK
Another question: what are you using to play the Youtube video? I know the proprietary Flash plugin caused problems with Pulse at one point.
Flash plugin indeed (no problem with Pulse on Xubuntu). Should we better find an HTML5 stream for the test?
Sure, if you have a link then that would be preferable-- I think HTML5 should have better coverage than proprietary Flash (at least Debian doesn't ship with it, which I like). Or if you have VLC, opening a stream there-- it has a Pulse backend as well as a JACK one so it'd be easy to test with both. (But if you don't then HTML5 is best.)
-Jonathan
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Katja