OMF vs Track Import

[georgia]

Ok.. here's one i've never seen before..

we're doing a mix for the band MOE for an HDnet concert... We recieved all the files in Protools but we needed to reformat the session for 48Khz 16bit for a DOLBY-E encode due to the wrong format and the sessions being 48 tracks of 2 hour long files.... Huge memory eater...
So, We created a series of OMF exports for all the tracks via 3 OMF sessions of about 10+ tracks each. We created a single new session from these OMF Files that ended up being 30 tracks of AIFF 48Khz 16bit in a protools session. Ok great everything is perfect and works like a charm....

but wait, we missed 1 track.. So I simply dis a quick IMPORT TRACK from the old huge session. The files converted and imported correctly... except.. the audio was off by 1 frame from all the other files that came in via OMF. I then created an OMF file of the 1 track and then imported the OMF data as I did on the other tracks... NOW, the track is properly lined up and matched perfectly.

We compared the Audio track that was AUDIO TRACK Imported and the track that came in via OMF. They are identical in size, original time stamp and everything except the audio is 1 frame late on the IMPORT AUDIO track and exactly aigned in the correct spot via OMF.

So my questions:
Why would the audio be off by one frame from each other using these 2 methods... Shouldn't they be identical? Is OMF off by 1 frame for ALL the tracks or is the one AUDIO IMPORT track off by 1 frame? Why do the OMF tracks and the Audio Imported track have the exact same start location and the exact same time stamps, but the audio in the file that was imported seemed to be off by 1 frame?

Beats me... I've never seen this before...

MAC OS9.2 PT 5.1.3 Digitranslator
Original session was recorded on MOTU then Protools 5.1.3 was utilized to create the PT 48Khz 24bit SDII session. The original session was so big that we couldn't run it smoothy and we needed to create AIFF 16bit for delivery, so we utilized OMF to consoliate with 10 sec handles at 48Khz 16bit AIFF FIles...
Again it all worked fine and the client is happy as a clam, but this I wanted to see if anyone else has any info about these two import methods beinig off by the 1 frame...


cheers
geo

[Richard Fairbanks]

Hi Georgia! Curious...are you saying the IMPORTED track was wrong (compared to the original sd2 session), or the OMF'd tracks were all wrong by one frame? Which direction was the error? I'd love to try and duplicate the problem (not that I've got the time this week to fiddle!) You exported from 5.1.3 and imported into...5.1.3?

Digitranslator has had a bug for years where sometimes, depending on session start time vs. omf start time, audio tracks come in a SAMPLE out of sync and Avid video comes in a full frame wrong, but yours does not sound like the same bug.

[georgia]

Hey Richard

I'm actually not sure which one is wrong, but i believe the OMF is wrong and the track import is right. I'm going to check it tonight. Thanks for the note about the sample prob.. Maybe it's related to that. The sessions are in fact all 5.1.3 off the same machine. go figure....
oh, btw the original audio was recorded in MOTU at the concert and transfered to Protools later.
I wonder if this has anything to do with it.

Man, your bug sounds like a pain-in-the-butt.... good luck sorting it out. I hope the digitech note helped...

cheers
geo