Topic: Mix audio to video in post or on-the-fly?

[bconnolly]

If you were doing video for a show and you were running your mics as well... would you run the audio straight to the camcorder while recording or would you wait to mix it in during post?  Does a DV tape compress the audio a ton?

[spearheadtaper]

mix it in post.... 

[fsulloway]

We've run out of the 722 into the vid cam w/ decent results on numerous occasions. Obviously you'd be able to maximize audio levels though if you work w/ it in post.

[John Kary]

First off, to my knowledge, you will not lose any audio data by running into a video camera as opposed to a MD/DAT deck.  Your only limitation will be the usually poor mic preamp on the camera that may introduce a higher noise floor or overload too easily.  The benefit you gain is exact sync audio to the video without having to mess with it in post.  I personally would stick with it going to an external recording device.

[guitard]

Definitely go with a separate recording device for the audio.  The only downside that I've seen is that people have a hard time doing both and end up doing neither particularly well.  This is especially true for the hardcore audio taper who decides to start running a camera - he focuses in on the audio too much - because that's what he's used to doing.

If you have a second mic - just hook that to the camera and use both if the cam audio turns out OK.  Invariably the two audio recordings will have different parts of the sound that was at the gig, and sometimes when they are mixes together - they sound great.

[BayTaynt3d]

For starters, the DV spec records 2 channels at 16/48 uncompressed PCM (or 4 channels at 12-bit, but we won't even bother discussing that lunacy). In general, as stated above, the audio sections in lower-end cams including prosumer cams as nice as the DVX100, PD170, and XL2, aren't nearly as good as a lot of the audio-only rigs being run around these parts. Furthermore, many cams, pretty much all consumer cams, and even some prosumer cams, don't even have balanced XLR inputs (although the three listed above do). Many cannot take line-in levels either. Then you get into the business of getting XLR adapters designed for video that can switch mic/line-in (using a pad) and handle balanced XLR to unbalanced mini conversions -- yuk! So, the first thing to ask is what kind of camera are we talking about because some are WAY BETTER than others when it comes to audio?

That said, the ideal would probably look something like this assuming you have access to good audio gear (this is TS of course) and OK video gear. I would record as usual in an AUD-only sense, and if possible, send a feed/patch to the camera as well. This serves, multiple purposes: (1) you get a backup of the recording, (2) it'll make syncing in post a little easier, (3) and the AUD tape (outside of cam) will provide the highest fidelity. Finally, if you do sync in post, I'd also do some of the following: (1) run the cam without stopping as long as possible (less sync points), (2) do a head and tail "slate", which without a clapper board can be as simple as getting everything rolling/recording, then clapping LOUD into the audio being recorded by the cam and the AUD and make sure you can "see" the clap in the video (and if possible, do the same thing at the end, aka "tail slate"), and lastly, record your AUD at 48 kHz (or at least resample to that before dropping into your editor in post, because the DV audio will have been running at this rate, and this can help a tiny bit with sync/drift). Then in post, you'll need to sync up at the start (hopefully with the head slate/clap), and then check the tail to see if you had drift, if so then stretch without chaging pitch such that the tail slate lines up too.

And one more thing, if you can't send a patch to the cam for whatever reason, youcan still do a lot of the things described above to help with sync in post. But, if you can manually change the audio levels on the camera, do it. Sometimes (most times), the on-board camera mics will brickwall and distort so bad, that it can be hard to use the camera's audio to sync to later. So, if possible, turn off the camera's auto-gain-control, put it in manual, and drop the levels way low, so there is at least some decent audio from the on-board mics to help with syncing later.

Anyway, those are some ideas, all or none of which might be helpful.