What Difference between "Frame Dropping" and "Sync To Audio"?

When synchronizing audio and video, you can chose in the "Timeline" editor between "Frame Dropping" and "Sync To Audio". Since the last option also makes Blender drop frames, I'm wondering what is the difference between the two options?

  • Wayne Dixon replied

    I haven't been able to find a full explanation for the differences other than something like it uses the "audio clock".  

    Which just leads me to believe that the the frame dropping option looks at the video clock(?)

    I don't even know if that a thing haha.


    I have always found that syncing to the audio is better for me, but you need to remember that both of those options drop frames.

    So you might see a spacing pop where there is no spacing pop, so you make sure you watch it on loop and always, always, always check the playblast before thinking it's 'finished'.

    'Play every frame' is the worst option for animators as it's going to lag and give you a false sense of the timing.

  • Ingmar Franz(duerer) replied

    Thank you, @waylow 😀! I've taken a look at the Blender 3.0 Alpha tool tips:

    1) "Frame Dropping" => "Drop frames if playback is too slow."

    => I suppose that it's for cases where you don't have any audio but the rendering calculations are too heavy for allowing the scene to be displayed in realtime.

    2) "Sync to audio" => "Sync to audio playback, dropping frames."

    => So, this is the option to choose for audio-video-synchronization


    Blender 2.79b says:

    1) "Frame Dropping" => "Play back dropping frames if frame display is too slow."

    2) "AV-sync" => "Play back and sync with audio clock, dropping frames if frame display is too slow."


    In Blender 2.79b, you could check "AV-sync" and "Frame Dropping" at the same time. In Blender 3.0 Alpha, you have instead a dropdown menu where you can only select either "Frame Dropping" or "Sync to Audio". I suppose that the developers changed it because the old user interface caused some confusion since the "AV-sync" already contains a "Frame Dropping" functionality so that you don't need to check the explicitly named "Frame Dropping" option anymore which is for a pure video playback without any audio.



  • Wayne Dixon replied

    Yeah, looks like they just made it a little clearer haha.