<html><body><div style="color:#000; background-color:#fff; font-family:arial, helvetica, sans-serif;font-size:12pt"><div id="yiv6311629443"><div><div style="color:#000;background-color:#fff;font-family:arial, helvetica, sans-serif;font-size:12pt;"><div id="yiv6311629443"><div id="yiv6311629443yui_3_7_2_34_1370273908578_67"><div id="yiv6311629443yui_3_7_2_34_1370273908578_66" class="yiv6311629443yui_3_7_2_34_1370273908578_55" style="color:#000;background-color:#fff;font-family:arial, helvetica, sans-serif;font-size:12pt;"><div id="yiv6311629443yui_3_7_2_32_1370273908578_55"><span><br></span></div><div id="yiv6311629443yui_3_7_2_32_1370273908578_73"><br id="yiv6311629443yui_3_7_2_32_1370273908578_57"></div> <div class="yiv6311629443yui_3_7_2_32_1370273908578_59 yiv6311629443yui_3_7_2_34_1370273908578_56" id="yiv6311629443yui_3_7_2_32_1370273908578_60" style="font-family:arial, helvetica, sans-serif;font-size:12pt;"> <div
id="yiv6311629443yui_3_7_2_32_1370273908578_79" class="yiv6311629443yui_3_7_2_32_1370273908578_63 yiv6311629443yui_3_7_2_34_1370273908578_57" style="font-family:times new roman, new york, times, serif;font-size:12pt;"> <div id="yiv6311629443yui_3_7_2_32_1370273908578_78" dir="ltr"> <hr size="1"> <font id="yiv6311629443yui_3_7_2_32_1370273908578_77" face="Arial" size="2"> <b id="yiv6311629443yui_3_7_2_32_1370273908578_76"><span id="yiv6311629443yui_3_7_2_32_1370273908578_75" style="font-weight:bold;">From:</span></b> katja <katjavetter@gmail.com><br> <b id="yiv6311629443yui_3_7_2_32_1370273908578_84"><span id="yiv6311629443yui_3_7_2_32_1370273908578_83" style="font-weight:bold;">To:</span></b> IOhannes m zmoelnig <zmoelnig@iem.at> <br><b id="yiv6311629443yui_3_7_2_32_1370273908578_88"><span id="yiv6311629443yui_3_7_2_32_1370273908578_87" style="font-weight:bold;">Cc:</span></b> pddev <pd-dev@iem.at> <br> <b
id="yiv6311629443yui_3_7_2_32_1370273908578_92"><span id="yiv6311629443yui_3_7_2_32_1370273908578_91" style="font-weight:bold;">Sent:</span></b> Monday, June 3, 2013 7:09 AM<br> <b id="yiv6311629443yui_3_7_2_32_1370273908578_96"><span id="yiv6311629443yui_3_7_2_32_1370273908578_95" style="font-weight:bold;">Subject:</span></b> Re: [PD-dev] jack dbus?<br> </font> </div> <div id="yiv6311629443yui_3_7_2_32_1370273908578_99" class="yiv6311629443y_msg_container"><br>On Mon, Jun 3, 2013 at 9:04 AM, IOhannes m zmoelnig <<a rel="nofollow" ymailto="mailto:zmoelnig@iem.at" target="_blank" href="mailto:zmoelnig@iem.at">zmoelnig@iem.at</a>> wrote:<br><br>>> On 2013-06-02 08:51, Jonathan Wilkes
wrote:<br>>>> Of course these are just the latencies in the settings-- I haven't<br>>>> done the actual measurements
yet.<br>>><br>>> it would be interesting to have actual measurements.<br>>> everything else is wild speculation.<br><br><br>>Right. I would propose the following measurement protocol:<br><br>>(setup/usecase A: Pd only through ALSA)<br>>1. In Pd using ALSA backend, run sine test signal in 'Media > Test<br>>Audio and Midi...'<br>>2. Set Pd's buffer to lowest possible value such that there are no I/O<br>>error messages or audible dropouts during 'normal Pd use', that is,<br>>while clicking (radio)buttons or switching between already loaded Pd<br>>windows.<br>>3. For this nominal latency setting, measure actual roundtrip latency<br>>via line loopback or speaker / mic loopback, using patch<br>>latency-tester2.pd which was attached to my May 29 post in this<br>>thread.<br><br>Ok, I just need a loopback cord.<br><br>(I tried using [r~ foo]---[s~ foo] but when I drag the containing patch to move<br>it
down toward my physical connectors on the laptop, it goes outside the screen<br>area and I can't tell whether it's lined up correctly with them. I think the problem<br>is that my screen only bends down 45 degrees, so the patch doesn't end up on<br>the same plane as the physical inputs. Also the wire in Pd is too far to the left<br>so I probably can't even shove the objects far enough into the cavity to get them<br>to connect without breaking the connection.)<br><br>>(setup/usecase B: Pd and PulseAudio through JACK/ALSA)<br>>4. Set up a routing with Pd and PulseAudio as JACK clients.<br>>5. In Pd, run the sine test signal. Simultaneously, play this video in<br>>a browser while routing it's sound through PulseAudio / JACK:<br><a rel="nofollow" id="yiv6311629443yui_3_7_2_32_1370273908578_125" target="_blank"
href="http://www.youtube.com/watch?v=_63Cc6vPFVI&feature=youtu.be">>http://www.youtube.com/watch?v=_63Cc6vPFVI&feature=youtu.be</a><br>>6.
For this combination, get the lowest nominal latency in Jack such<br>>that there are no I/O errors in Pd, or audible dropouts in either<br>>audio signal. JACK must be restarted for a new buffer setting to take<br>>effect. This is the most time-consuming aspect of the measurement.<br>>7. For this routing and settings, measure the actual roundtrip latency<br>>through Pd.<br><br>In all serious now... :)<br><br>Don't we want to compare straight to ALSA to pd to JACK to ALSA,<br>just with Pd running? Having Pulse in the mix is good to measure as<br>well, but I'd like to get a handle on the "JACK adds no latency" statement<br>and comparing additionally with just Pd running through JACK will simplify<br>that.<br><br>Also, it may be helpful to add: Pd through JACK, VLC using JACK backend<br>through Jack and compare it to the one using PulseAudio through JACK.<br><br>Another question: what are you using to play the Youtube video?
I know the<br>proprietary Flash plugin caused problems with Pulse at one point. Regardless,<br>we should all be using the same plugin for the comparison. (Or maybe just<br>the same network stream through VLC, one using JACK backend and the<br>other using the Pulse one.)<br><br>>My results for Panasonic CF-19 1 GHz Core2Duo, Xubuntu 12.04, built-in<br>>soundcard, no preemptive kernel:<br>>- setup/usecase A: 15 ms buffer in Pd, 18 ms measured roundtrip latency<br>>- setup/usecase B:
15 ms buffer in Pd, 23.2 ms (2*512 samples) buffer<br>>in JACK, 49.3 ms measured rountrip latency through Pd<br><br>RFC: for the Pd preferences dialog, I think the "delay" entry box should<br>be either disabled or replaced with a label that says "set with JACK" when<br>the JACK api is chosen. On my system setting the delay from within Pd has<br>no impact-- you can even set it to zero!<br><br>-Jonathan<br></div> </div> </div> </div></div></div></div></div></div></div></body></html>