sync using video in 23.976?

I edited video in Blender that is 23.976 fps and am using JackPilot to lock Blender with Ardour to edit sound. All systems are run by Jack. I have been duplicating the same sound clip, cut end to end, and am finding that the sound is drifting out of sync with the picture in Ardour at around 20 minutes. Why is it losing sync? Is there a better way?

Hard to say exactly, could be an issue with clip length (If the clip isn’t the exact length you need the more times you duplicate it the more out of sync it will be), could be an issue with how Blender manages sync as well. I haven’t spent a lot of time with it’s jack integration to be able to say how good it is or isn’t, but jack sync is measured in audio samples, whereas video frames are a MUCH more coarse measurement. I suppose it is possible that Blender just doesn’t have as strong timing as is required as well, not sure(And not meant as a slight against Blender, it wasn’t intended to do audio editing, or really video editing for that matter).

Do you have a longer (>20 Minutes at least) 23.976 video that already has audio encoded that you could import into Ardour? If you import that and the audio and video remain in sync, then it is unlikely to be an issue in Ardour that you are seeing.


yes, somehow the clip was extended in the middle. New user failure. Thank you