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syncing MTC-based digital multitrack with DV in NLE??

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syncing MTC-based digital multitrack with DV in NLE??
on Aug 2, 2005 at 8:08:47 pm

Our multi-use theatre (film & live event) has a Roland VM-7200 digital mixer to which I've recently added (now that they are available at a reasonable price) VSR-880 digital multitrack capability (currently one, planning for three total). One of my near-term goals is to be able to market ourselves as having the capability of allowing local bands etc to record themselves 'live' at our facility with a proper mixdown later. We're not looking to compete with the multi-million dollar remote trucks or produce studio-quality CDs, but I think we could make a few bucks with what we have. That part is pretty straightforward and I'm not too worried about the details of it.

However, what I would like to do eventually is combine a multi-camera video shoot along with it and edit the resulting audio and video down into DVD format and produce a reasonable quaility end result for the same local clients. The theatre itself is run as a non-profit and we still have construction debt to pay off (which this might help with), so cost is a definite issue. Expensive HDV or DVCAM editing suites are unfortunately out of the picture. I've looked around and my first idea is to use DV-format cameras capturing directly and independently via IEEE-1394 to multiple hard drives via FireStore or equivalent, then use a PC-based NLE to edit the footage, using the house mix audio to edit the video with. Syncing to the Roland VSR-880/VM-7200 to edit the multitrack audio is the issue. It speaks MIDI Time Code, not LANC/SMPTE/RS-422/etc.

Does anyone know of any relatively cost-effective hardware and/or editing software that can produce MTC out of a MIDI port based on internal DV timecode played back on a DV-acquired video file, or vice-versa? and/or can take a final stereo (or 5.1) mix via AES/EBU or S/PDIF input on a PC and replace (in sync) the existing audio track on a DV-acquired PC video file?

Also (and this might be a little off-topic), does anyone know if the internal TC generators on consumer/prosumer DV camcorders have the precision and stability to be in-sync with each other after an hour and a half of straight recording? I can envision using a digital clapboard to set a reference point to sync the start-point of the different independent video recordings, but will that be sufficient? I'm afraid that cost will probably prevent obtaining cameras where jam syncing can be easily accomplished...

Any input (including suggestions on other ways to handle it, or comments that I'm crazy :) ) would be appreciated.


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Seth Bloombaum
Re: syncing MTC-based digital multitrack with DV in NLE??
on Aug 3, 2005 at 4:37:00 pm

Vegas is the top NLE for DV and multitrack audio. It started life as a protools wannabe for the PC but now is an amazing editor for video and audio. Note that it doesn't conform to the Avid interface standard that so many NLEs have used, but it does have a more PC-like interface that power users are extremely productive with and really enjoy.

I regularly slurp in stereo from HHB pro minidisc and sometimes slurp in 24 track from an Alesis HD24 and sync by hand to action and reference audio from a camera mic. (Sony PD150).

One of the key features of the HD24 for this application is that there is an available firewire interface for its drives - you just plug the drive into your pc, launch the Alesis software, and transfer your files to a PC drive. Simple and fast. This can be a tremendous issue with other multitrack recorders - you don't want something like aes/ebu or s/pdif to be your only way to slurp audio in, because then you're looking at perhaps 8+ transfer hours per recorded hour of 16 track. ADAT lightpipe will get you 8 tracks at a time, but I think it's pretty much a legacy method from the ADAT days and isn't included with my favorite sound cards.

Other features of the HD24 include 24 analog inputs and outputs (no extra cards to buy), uses standard and inexpensive ATA133 hard drives, caddies for the drives only $25. Note that another challenge with this kind of work is how you archive projects. Putting hard drives on the shelf turns out to be the only way, so using inexpensive standard drives helps.

I just harness up with a 24 channel TRS-TRS snake from the direct outs of the board to the HD24. Done. (don't forget to hit record!) And yes, multiple HD24s can be synched as well.

I've never had sync drift problems over 1+ hours of continuous DV-prosumer video.

My understanding is that Vegas can generate what's needed for midisync but I've not used that. If it works as advertised your suggested workflow would probably be fine. Vegas can be downloaded as a demo - see if it works (you'll need some pc-midi interface).

That's my preference and workflow - slurp it all in to the PC and don't bother with timecode chase. BTW, Vegas has tremendous support in forums, and the Cow has a great one. Check it out.

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