Laying back score from PTLE into Avid Symphony

Posted: Mon Feb 04, 2002 5:22 pm

Right now I’m working on a project for a TV documentary. The editor gave me the beta at 30(nd) - (42 minutes long). I’m recording (scoring) using PTLE-001. My Black Burst generator is feeding the Betacam and a Motu Digital Timepiece(DDT). The VTR is sending TC to the DDP, the DDP sends clock (at 4 Cool

via spidif to the Digi 001 and converts the incoming TC to MTC as an address source to the 001 as well.

At last I have finally achieved perfect sync with the 001. I can run the entire 42 minute session and hit all my frames on spot, zero drift!! I have one little problem though. The DDP (I guess ‘cause it’s being fed Black Burst?) is forced into 27.97 frames (nd) and cannot be changed unless I disconnect the burst cable. If I push the button to change the frame rate to 30 on the DDP it automatically switches itself back to 27.97. So of course my session set up must also be set at 29.97nd in order to sync-lock. I have burned the whole session as a .wav file at 48/16 to be loaded into their Avid symphony PC rig for layback. The editor always uses 30nd as a time base. When we go to import this file, the symphony will detect that the file has TC and ask to choose a frame rate via dialog box. What do we choose? Her time base of 30nd or what I was using in PT, 29.97nd.

Just as a note:
As we all know there is no TC ruler in LE but the funny thing is that when I change the time base in the LE session set up to match the 30nd on the Beta, the minute seconds counter in LE runs in sync with the TC burn in on the tape but my audio starts to drift after about 5 minutes. When I switch it back to 29.97nd, the audio syncs up perfectly (for the entire 42 minutes) but the counter in LE does not match up to the beta or the incoming TC in the session set up window. This makes me even more confused...

Anyway. The bottom line is that I’ve got the audio and picture to sync lock. My main question was what to tell Avid Symphony on import.

Thanks,

dk

Posted: Tue Feb 05, 2002 8:08 am

Butterhead,
As with any uncharted territory you may have some trail and error to test all the workable solutions. I can offer some helpful insight which may lead you to a better first choice however. First, the beta source tape that the editor gave you couldn't have been recorded at 30FPS. Video decks always record at 29.97FPS due to the power cycle of 59.94Hz. We think in terms of 30FPS/60Hz as gross generalizations because it is easier to say. Therefore, the material you dumped into your DAW is really 29.97 not 30. This is why you are able to get sync lock using your blackburst generator. As far as dumping it back into the Avid Symphony, my guess would be to select 30FPS unless the Symphony offers a 29.97 selection. I am not very familiar with the Symphony, sorry! I think when Avid says 30FPS they really mean 29.97 video sync. All of this is viable at either Time Code rate, Non-Drop Frame or Drop Frame as long as you are consistent throughout. I hope this is helpful. I will keep posted on the results. I would love to know which one works for you.
Cool

Posted: Tue Feb 05, 2002 9:04 pm

Success!!

You are absolutely correct. 30 frames is a mute point all together. The only important thing is to run my session the same as the incoming TC and that’s all there is to it!

We imported my 42 minute .wav file into the Avid today, chose ND on import and every freaking thing hit right on frame for the duration, just like I scored it! I actually cheered out load. It was a beautifully thing to behold Wink

Thanks for the great reply and, Happy syncing!

Regards

Dan-

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