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tc probems - best solution


tonymuricy

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I' ve just finished a DVCam shooting of a DVD about one of Brazil´s greatest composer and player.

By request of the finishing house, we run Rec Run 29,97 Drop FrameTC on camera, and sent it from the camera to my Fostex PD4 dat recorder TC input.

But now we found that  in almost every take the tc from the camera freezes for a few seconds then runs normally again, then freezes and so on.

The Avid is not accepting the DV tapes like this, and they can´t be logged. There´s a suggestion that we copy all tapes again with a new continous TC, so the avid may read it. But then we´re going to loose the TC sinc  with DAT tapes, which should be resinced in the final steps to be mixed.

As in 20 out of 24 tapes I´ve sent the line out of the PD4 to the Line In inputs of the camera, I´m suggesting that they use the sound actually on the tapes as the sound source for the editing and mixing. This way even if they change the TC on camera tapes, the sound is actually there, and if imported into the avid correctly, and handled correctly by the image editor, it willl reach the mixing with the necessary quality. I´m also suggesting that if they go this way they sinc immediately the 4 camera tapes which run with camera , mike  and my sound on dat tape only.

I know this is not the perfect way to go, but now we have to find the best sound solution with the last cost for the production company.

If anybody has some other suggestions, they will be most welcome.

Thanks a lot

Tony Muricy - Rio de Janeiro

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You could clone the DAT tapes between two TC DAT machines, with the time code running through a TC generator set  to continuous re-jam.  Thus the TC gen will pickup the TC when it is good and keep it running when it drops out, and you send it on to the 2nd, recording deck.  If you can get all the gear to be looking at house-sync or word clock from the playback deck then the sync will hold for as long as you rolled.  The editors are correct that IF the TC on the DATs is ok and in sync with that on the videotapes, they can cut with the camera audio and the DAT audio can be reconformed later.  The truth is that the conform done later could also be done manually, by ear, if the TC issue is never resolved.  It is more work but will be ok.  (It used to be that all multitrack conforms for music shows were done this way.)  I'd try this DAT clone+ new TC trick right away with the 4 camera rolls you have that I think you said don't have any sound.

good luck

Philip Perkins

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Philip:

Thanks for your reply.

But this TC problem is a bit different from what you understood: The question is that the TC is not missing (drop-out) sometimes, but it is FREEZING. So we have, let´s say, TC frames 1, 2, 3, 4, 5, 6, 6, 6, 6, 6, 7, 8, 9,...

One option was that when they cloned the tapes, maybe we could copy the bad TC into camera Ch 1 audio track, and mixdown both audio tracks into camera Ch 2 audio track, just for the editing. The we could keep this bad TC track as a 4th audio track in the Avid, carry it up to the end of the editing, and then use this TC on audio track 4 on it´s good points to find the audio sinc on the dats. Because there are good TC moments both in camera and on DAT tapes. But actually I don´t think that the Avid will be able to track the bad (frozen frames) TC on the Dats either.

So I think that maybe the best option would be: to check the audio quality of the audio tracks on the camera tapes. If they´re ok, and they should be, because I´ve sent the Fostex PD4 line outs to camera, and these are recorded on digital tracks on DVCam, then they could consider the camera tapes audio to be the final audio, because there´s quality, and they´re are already sincd with the image! This way they could clone the image tapes WITH it´s audio tracks, sinc, which are going to be the final tracks, and not use the DATs audio at all, except in the four image tapes without audio, which they´ll will have to sinc manually, or where the image tapes audio have any kind of problem - dropouts, saturation, etc...

Thanks a lot

Tony

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Philip:

Thanks for your reply.

But this TC problem is a bit different from what you understood: The question is that the TC is not missing (drop-out) sometimes, but it is FREEZING. So we have, let´s say, TC frames 1, 2, 3, 4, 5, 6, 6, 6, 6, 6, 7, 8, 9,...

One option was that when they cloned the tapes, maybe we could copy the bad TC into camera Ch 1 audio track, and mixdown both audio tracks into camera Ch 2 audio track, just for the editing. The we could keep this bad TC track as a 4th audio track in the Avid, carry it up to the end of the editing, and then use this TC on audio track 4 on it´s good points to find the audio sinc on the dats. Because there are good TC moments both in camera and on DAT tapes. But actually I don´t think that the Avid will be able to track the bad (frozen frames) TC on the Dats either.

So I think that maybe the best option would be: to check the audio quality of the audio tracks on the camera tapes. If they´re ok, and they should be, because I´ve sent the Fostex PD4 line outs to camera, and these are recorded on digital tracks on DVCam, then they could consider the camera tapes audio to be the final audio, because there´s quality, and they´re are already sincd with the image! This way they could clone the image tapes WITH it´s audio tracks, sinc, which are going to be the final tracks, and not use the DATs audio at all, except in the four image tapes without audio, which they´ll will have to sinc manually, or where the image tapes audio have any kind of problem - dropouts, saturation, etc...

Thanks a lot

Tony

The camera tape audio may be ok but it is not as good as what your PD4 recorded--the analog audio electronics  in the cameras are inferior in every way to those of the Fostex.  What you need in order to digitise your tapes in sync into the Avid is good  TC, and the method I'm told you will do this for you, freezing code or no--the TC generator will continue to count ahead over those freezes and then resync when the DAT TC starts up again.  If the DAT TC is very intermittant, you could do a one-time jam sync of the code to pickup the number at the start of the recording, and if the DATs  and the TC gen are clocked together then the code will match what is on your video tapes.  In any case, the takes in a concert recording are likely to be few and long, so a manual sync of your DAT audio, once digitised into the Avid, should be very possible and probably the fastest solution, via waveform matching in the Avid.  I've done many concert shoots with small video cameras w/o TC features where the audio line feed became the sync track as well, and my audio was synced to that line feed track via waveform match in FCP systems.  The audio they have is probably fine for cutting, and the resync could happen in audio post, where the tools available allow a much finer sync match.

Philip Perkins

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Philip:

Thanks for your reply.

But this TC problem is a bit different from what you understood: The question is that the TC is not missing (drop-out) sometimes, but it is FREEZING. So we have, let´s say, TC frames 1, 2, 3, 4, 5, 6, 6, 6, 6, 6, 7, 8, 9,...

Tony,

One other thought.  If you could get your hands on a Non-linear recorder you could clone your DATs to a NL and clean up your audio this way.  This would assume that you would have enough good code at the head of each take to jam the NL recorder.

Since non-linear files use only a timecode stamp at the head of the file and the rest of the code is created from that by counting samples, you could connect the TC out of your DAT to a NL recordrer (let's say the 744, for instance.. :-) ) and the Digital out to the digital in.

Set the recorder to external code, roll the DAT and make sure the recorder locks up to the code.  Roll the recorder and disconnect the TC cable.  At least in the 744, while in EXt TC/cont mode, once the timecode cable is disconnected, the timecode will "free-wheel" until the recording is stopped.

It would be pretty tedious to do.  You would have to start and stop with each camera take so that you get the correct starting code on each file, but I think it could be done.

I can only speak to the 744 for sure, your mileage may vary with all the other flavors of NL recorders.

---Matt

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  • 2 months later...
Guest Eric Lamontagne

Just to pipe in here. I

'm guessing that editorial is really just having problems with the DV import. Avid does not like funky timecode for certian. Your idea of using the camera's audio as editing guide/master if it's useable sounds great. Their suggestion of restriping the code to a new tape seems like a must, not that it's really your responsibility as the location sound guy! Audio auto conform after picture cut to the Avid's EDL timecode probably won't work unless the NL recorder option is used (great idea!).

Did you have clapper sticks? Why not just use these? It seems like the camera has produced this bad timecode on the production's suggestion and so it certianly leaves you scott-free.  Problems might come without the conventional sticks.

Question: We are assuming time of day timecode, is this the case? Also, did you mix for summing to mono? This process as you suggest would drastically affect the sound quality, careful here!

All the best,

Eric

PS. an ounce of learned knowledge in post is worth it's weight in GOLD!

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Guest tourtelot

Not to be TOO cynical but when will they ever frickin' learn??  Let's use something other than a cheap POS home video camera on these "really important" jobs, eh?

D.

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