Global offset/delay for BPM
  • jasonbeyers
    Posts: 41
    Joined: Mon Oct 08, 2018 7:16 am

    Global offset/delay for BPM

    by jasonbeyers » Fri Jun 19, 2020 11:50 pm


    As an extension of the per-projector or per-fixture delay idea posted at ... ctor+delay, it would be great if there was a delay/offset slider for the global BPM in Madmapper.

    Often I find that external clock sources are not producing the correct phase, and have also noticed this with Madmapper's built-in BPM detection via audio. Waveclock on Mac has built-in latency compensation to shift the clock that it produces, so things are fine when I'm driving Madmapper BPM using Waveclock.

    But I have no such option when the BPM is coming from other software, including DJ software. If the clock isn't perfect (say, from internal software delay), then beat-synced compositions I made in Madmapper are off. And the new "Resync" options added in v4 beta (for all BPM sources) is helpful, but it doesn't solve this particular problem.

    Add a global slider for offset / delay / phase shift for the BPM, that takes effect regardless of what your BPM source is. That way, users can compensate for software delays elsewhere, including with Madmapper's built-in audio BPM detection or even Ableton Link. The slider could range from -150ms to +150ms, for example. A negative value means that MM would hit beat=1.0 before it would have otherwise (as seen by a Material, for example), and a positive value would mean it hits beat=1.0 later than normal. Significant shifts would mean that your project would be a bit late in responding to sudden *changes* in BPM and could miss some beats at those times, but that seems like a good trade-off for many cases.

    TouchDesigner and Resolume both let you adjust how those tools interpret an incoming clock signal, and it would be great if Madmapper offered some control in this area, as a "catch all" solution.

    Thanks for your consideration!
  • AEK_98
    Posts: 26
    Joined: Sun Apr 07, 2019 7:23 pm

    Re: Global offset/delay for BPM

    by AEK_98 » Thu Jun 25, 2020 2:37 pm

    Hi Jason,
    According to our long experiments, I can say that getting rid of the delay by introducing compensation is not very effective. For many reasons. One of the main ones is that the delay is not constant. It varies greatly in time and you will have to devote a lot of time and energy to the issue of its compensation during the event. If there is a delay in your system that interferes greatly, let the more correct one be to look for and eliminate the cause of this delay and reduce the latency of your system.

    Best regards,

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