Issue with hooktheory calculating bpm changes and video sync

when making a song, the video sync does not account for bpm changes.

Hi and thank you for reporting this.
I’m not sure what’s exactly happening when you have a bpm change. The example of your link has no Video attached anymore, perhaps it got canceled while sharing the project.
Is the transport cursor wrong, does it calculate a wrong tempo or what exactly is the problem?


Please correct me if I’m wrong, but I think the issue here is that Hookpad calculates the pace of the transport cursor by relating the duration of the video section to the number of beats in the Hookpad project. That way when using the youtube playback, the transport cursor is always moving through the Tab at an even pace, regardless of any tempo changes.

The only way to bypass this issue currently would be to transcribe each segment with a differing tempo in a separate TheoryTab section, but that only works if the tempo changes occur between different sections of the song. For example if a tempo change occurs during the chorus of a song, there’s nothing we can do to ensure the playback is in sync, since the database only allows for one chorus per TheoryTab.

A good example of this would be the chorus of Green Day’s Before The Lobotomy. The playback starts out in sync, then gets progressively more and more out of sync and at the very end it’s back in sync again. This is because the chorus is at roughly 136 BPM, but it slows down at the end, which causes the 16 bars to be significantly longer than 16 bars at a strict 136 BPM would be.

The easiest way to fix this would probably be to incorporate an option to increase the number of sync points. That way you could just sync each segment with a differing tempo individually and the playback would be perfectly in sync.

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