AAF and Reference off by subframe


Brought in an AAF and reference and they both start at the same TC, but are off by half a subframe on playback and also on export.

I do not have this issue in PT. Works round trip both ways.

Sequence is from Media Composer.

What is the reference?

i think that he means audio mixdown from video track is the reference.
if so, i have the same issue.
and i am using quicktime prores (the recomended codec)
i have half frame slip.
i think that nuendo is shifts audio when extracting from video track.
a bug probably.

Audio extracted from video can neverever-ever-ever-ever be a reference track.


of course it can not be the reference, i was just pointing out a possible workflow issue.
but i remember a strange bug about a year ago when the aaf was out of sync. by half frame…strange.
maybe it was media composer update or nuendo update that sorted it out.

I consistently see a differential between ref picture and AAF of 3/4 frame + 3 subframes, these are projects that have edited on Premier Pro.

Define “reference”.

The ONLY reference is a 2pop on each audio channel and a White Flash of 1 frame in video.
Anything else is wrong.
Audio extracted from Video is pretty much always delayed vs. the picture for video playback reasons. So YES, audio extracted from a video will pretty much always be out of sync. Some NLE’s only snap to frames, which can result to offsync. So, I repeat, the only correct reference is a 2pop with White Flash.


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I just exported an AAF and a mixdown WAV of the same sequence from Autodesk Flame, consisting of a VO track with a ton of edits and a stereo music track with a few edits.

Importing both into Nuendo, If I invert the phase on the WAV against the AAF tracks, I will get a tiny bit of leakthrough where it doesn’t cancel perfectly on a handful of random clips (VO and music) but I can “correct” these by nudging them 1 sample, sometimes + sometimes -.

In the almost 50 audio clips, I didn’t find one that was any more than 1 single sample off.

Take what you will from it.

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Sounds like sync to me!

Me too!

I come from the days of trying to force multiple reels of 35mm Mag Film ( ie sound film ) to sync by getting “SYNC” stickers to line up on the playback heads of giant 35mm players!

A sample here or there? - meh! :wink:

ok, so today i received a bunch of aaf from media composer (latest version).
i opened one and it is in perfect sync with audio mixdown and 2pops and flashes.
i also asked editor to insert pops and flashes every 10 min on timeline to see if there is some sort of “sync drift”. but sync is sample perfect.
the only thing that is out of sync is mixdown from video track but that is not the reference.
if you use NLE that can cut material in "slip"mode (in between frames), aaf export will quantise those clips to frames, resulting in about half frame off-sync per clip (davinci resolve).
if i find some issues with my latest aaf’s, i will post it here.

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