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Will digital audio recorders stay in sync with DV video?
If I use a Fostek digital audio recorder (records to CF card) while I shoot digital video, is it likely that the sound and video will remain in sync (assuming I start them in sync when editing)?
Thanks.
James (seatlanta) -
12 Replies
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It should, but…and this is anecdotal… Know a guy editing a project on FCP shot with a DVX 100 in 24p, he recorded the audio to a DA88. His buddy captured the files on another computer and then gave him all the audio on a harddrive – he is now having the audio slowly drift out of sync over time. This is turning out to be a HUGE problem for obvious reasons, it might be worth doing a test…
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If it’s digital it should be ok, but even if it’s not, Vegas makes it very easy to shrink or stretch (Ctrl/Drag edge) so that it matches up – I’ve had audio from cassettes that were way out but didn’t take long to fix.
Peter Wright
Perth, Western Oz
http://www.allroundvision.com.au -
” If it’s digital it should be ok”
Digital recording is only as accurate as the internal clock of the recording and playback devices. This is why cheap voice recorders generally do a very poor job of recording audio for sync to video. Music recorders tend to be more accurate because a 1% error in the clock would never be noticed in a voice recording, but it would be a disaster in music.
You really won’t know until you try it.
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Doesn’t the Fostec have an optional module for reading timecode from the camera?
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The answer is “probably not”. Unless you have the ability to jam sync the recorder to the camera, you will experience a slight drifting of the audio when the take runs a couple of minutes or more. This is common and one of the unspoken bugaboos of using external audio. That’s why audio guys make so much money (LOL!). It’s not that difficult to re-sync, however. A quick and dirty trick is to keep both tracks live (assuming that you also have an audio track from the camera) and line up the slate markers. At first you will hear the audio just fine, but it will slowly develop an echo. When you first hear the echo, that’s where you will split the audio track and nudge it over until the echo goes away. Using the ambient from the camera audio track will help to fill the gap where you split the DAT audio. It’s time consuming, but in the end, it’s worth the time and trouble.
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I’ve done plenty of 1 hour takes with Alesis HD24 and HHB MDP-500 that sync perfectly from beginning to end.
Your mileage may vary, do test, but don’t assume that it will or won’t work until you test.
As Jim noted above, a mic on the camera is always helpful in establishing and checking sync.
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Oh Seth you lucky dog! I would imagine that a hard disk recorder and mini disc would hold sync better than a tape based system. I jsut put my DA-P1 up on ebay in the anticipation of going tapeless. I simply can’t imagine an hour take holding sync LOL! (Well, I can’t imagine an hour take PERIOD!).
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I’ve done a take of over an hour with audio recorded on a MiniDisc, with no synch problems.
The pain was having to transfer digital audio – via analogue – back to digital on PC in real time!
Peter Wright
Perth, Western Oz
http://www.allroundvision.com.au -
Peter, I think you’re right on the real question with digital recording – how do you get it out of the box and into the PC for post? If you’re trying to make money at this, workflow is everything.
The Alesis HD24 has a great optional interface that allows direct connection of their drive to PC or Mac, with awesome speed (you really need the speed with a 24 track 24/48 recording!) However, it’s a little bigger than most field recorders… 🙂
Marantz has the 660 and 670 flash recorders that offer near HD transfer speeds (flash memory is somewhat slower than an HD). However, you either need to buy lots of flash memory or dump off the recordings regularly. Same with the tiny M-Audio Microtrack 24/96 (user reports of some difficulties with long takes, it’s a pretty new product).
If you can afford the $1200-1400 USD, the HHB MDP-500 minidisc has USB and S/PDIF interfaces, but transfers in real time. Superb preamps and lots more, less expensive in Oz? HHB is a UK company.
There are a couple of new Sony MDs out, the MZ-M10 and MZ-M100 that do Hi-MD for uncompressed WAV as well as ATRAC compression and also have high speed (how high?) transfer back to PC.
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Yes, Seth – my MD is the “old type” so I have to play it realtime connected thru my sound card.
However, as with all time taking operations like rendering, I always have plenty of other things to do while they’re completing ….
Peter Wright
Perth, Western Oz
http://www.allroundvision.com.au
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