Timing Problem

Chris De Rock · Tue Apr 21, 2015 7:44 am

I have a strange behavior with rgb matrixes. i can tap the tempo and the tap-widget shows me the correct beat, but the fixures get a totaly different timing and are not in beat. Tested with QLC+ 4.8.5 GIT on OSX 10.6 and Raspberry.

plugz · Tue Apr 21, 2015 9:43 am

Hi,

please share a workspace file demonstrating the issue.

Thanks.

Chris De Rock · Wed Apr 22, 2015 6:38 am

ok, here are the workspace

janosvitok · Wed Apr 22, 2015 6:57 am

My guess is that tapping adjusts speed (step duration) but doesn't adjust when the step starts, so it the matrix (or anything else) is in tempo but may be off beat.

Chris De Rock · Wed Apr 22, 2015 7:33 am

No. As long as i tap the tempo, all fixures are in beat. if i stop tapping, the speed changes.

plugz · Wed Apr 22, 2015 8:33 am

Yup.

This happens quickly on short tempos (like 300ms).

This is something that is complex to fix :/

Chris De Rock · Wed Apr 22, 2015 8:36 am

This workspace is for the liveset of my band (rolling stones tribute) and the effect happens on every speed (i think from 70bpm to 130bpm. i tap quarter notes)

plugz · Wed Apr 22, 2015 9:14 am

Yes, it also happens on longer tempos.

Chris De Rock · Wed Apr 22, 2015 9:22 am

now i have found the file engine/src/mastertimer-unix.cpp (currently im on debian) and set the tread priority to time-critical but it changes nothing.

plugz · Wed Apr 22, 2015 2:26 pm

If you can compile from sources, the RGBMatrix + speed dial tap should look way better now.

Chasers have to be fixed still.

Chris De Rock · Wed Apr 22, 2015 2:26 pm

plugz wrote:If you can compile from sources, the RGBMatrix + speed dial tap should look way better now.

Chasers have to be fixed still.

Oh, great. Then i wait a few days (i need this at the end of the month)

plugz · Wed Apr 22, 2015 2:54 pm

Chaser timings improved too.

Here's a sample workspace for testing.

How to test the bug ?
- Start the chaser and the rgbmatrix
- You have to tap to a tempo that is not a multiple of the MasterTimer tick. Like 0s.290 (default tick is 20ms, so 0s.280 or 0s.300 may show a correct behavior)
- The speed dial tap and the lights will quickly be out of sync

How to test the fix ?
- Install QLC+ from git sources, do the same as above.

Now, a question: Would 1ms precision instead of 10ms precision be useful for you ?

Also, if you can compile from sources, can you tell the sync is better now ?

Chris De Rock · Wed Apr 22, 2015 2:59 pm

There seems to be another small problem: QTimer::setTimerType and Qt::PreciseTimer are not available in QT 4.8, so the patch is a little bit evil.

plugz · Wed Apr 22, 2015 3:43 pm

Sorry :/ fixing that...

plugz · Wed Apr 22, 2015 3:53 pm

Fixed, thanks for reporting my mistake

I don't know about the default precision of QTimer on Qt4 though, but it seems to be precise enough.

Chris De Rock · Wed Apr 22, 2015 3:53 pm

plugz wrote:Fixed, thanks for reporting my mistake

I don't know about the default precision of QTimer on Qt4 though, but it seems to be precise enough.

Now it looks (and works) good. Thank you for the fix.