Advice Please - Multitrack Recording and DV -AC-3 Encoder

Subject:Advice Please - Multitrack Recording and DV Posted by: dvdude Date:3/14/2004 2:31:32 PM I'm looking for some advice on how best to record multitrack audio and have it stay in sync with video recorded on Mini-DV. The goal is to capture multiple channels with a view to generating a DD 5.1 soundtrack in post. I figured this would be easy as both my camcorders output timecode over firewire during recording, so all I needed to find was a multitrack recorder that would use this timecode instead of it's internally generated one. Despite several extensive searches, I can't find a unit that will definitely take this timecode!! All the specs I've read seem to dance around the subject, with vague claims such as "The alesis hd24 can be synced to an external timecode via a BRC" and so forth. I'm sure some of you guys have already walked down this road?? TIA Andy
Subject:RE: Advice Please - Multitrack Recording and DV Reply by: Coordinator Alan Date:3/25/2004 3:39:17 PM If I understand your question correctly, you want to do live multitrack audio along with your video from two cameras. If this is the case, you need a multitrack recorder that can generate an internal Time Code Rate of 29.97fps (frames per second for video). Also you'll want to be able to record at a sampling rate of 48kHz or 96kHz and a bit depth of at least 16. In the past I have taken a stereo signal off of my mixer as a reference and sent a raw mix either direct out from each channel or sub out to the multitrack recorder. Then, in post, I would match up the tracks with the stereo recording to get sync, mix the audio using the stereo mix as a reference and then muting the original stereo mix when I was done. I did this recently with Vegas 4.0 and 16 tracks of audio to mix, it was a choir and band concert. I have accidently recorded audio in 30fps, only after about 6 minutes did I notice a sync problem. All I did to correct this was shift everything just before the obvious sync problem over one frame and do a cross fade between cameras to make up the lost frame. So if 30fps is all that you can afford, it's workable. Digital video can be forgiving.
Subject:RE: Advice Please - Multitrack Recording and DV Reply by: dvdude Date:4/1/2004 10:03:03 AM It sounds like you've done what I'm thinking about, but you're still having drift issues because more than one TC gen is in use.
Subject:RE: Advice Please - Multitrack Recording and DV Reply by: farss Date:5/7/2004 6:27:33 PM There are some audio recorders that'll accept external TC input or you can record linear TC to an audio track. But you'd need a way to convert the TC on the fwire out of the camera to linear TC and the recorders that take TC in seem to cost big time. I've seen a brochure on one that records 8 tracks to DVD media and another to HD but they were very expensive.

Subject:Advice Please - Multitrack Recording and DV

Posted by: dvdude

Date:3/14/2004 2:31:32 PM

I'm looking for some advice on how best to record multitrack audio and have it stay in sync with video recorded on Mini-DV. The goal is to capture multiple channels with a view to generating a DD 5.1 soundtrack in post. I figured this would be easy as both my camcorders output timecode over firewire during recording, so all I needed to find was a multitrack recorder that would use this timecode instead of it's internally generated one. Despite several extensive searches, I can't find a unit that will definitely take this timecode!! All the specs I've read seem to dance around the subject, with vague claims such as "The alesis hd24 can be synced to an external timecode via a BRC" and so forth. I'm sure some of you guys have already walked down this road??

TIA

Andy

Subject:RE: Advice Please - Multitrack Recording and DV

Reply by: Coordinator Alan

Date:3/25/2004 3:39:17 PM

If I understand your question correctly, you want to do live multitrack audio along with your video from two cameras. If this is the case, you need a multitrack recorder that can generate an internal Time Code Rate of 29.97fps (frames per second for video). Also you'll want to be able to record at a sampling rate of 48kHz or 96kHz and a bit depth of at least 16. In the past I have taken a stereo signal off of my mixer as a reference and sent a raw mix either direct out from each channel or sub out to the multitrack recorder. Then, in post, I would match up the tracks with the stereo recording to get sync, mix the audio using the stereo mix as a reference and then muting the original stereo mix when I was done. I did this recently with Vegas 4.0 and 16 tracks of audio to mix, it was a choir and band concert.
I have accidently recorded audio in 30fps, only after about 6 minutes did I notice a sync problem. All I did to correct this was shift everything just before the obvious sync problem over one frame and do a cross fade between cameras to make up the lost frame. So if 30fps is all that you can afford, it's workable.
Digital video can be forgiving.

Subject:RE: Advice Please - Multitrack Recording and DV

Reply by: dvdude

Date:4/1/2004 10:03:03 AM

It sounds like you've done what I'm thinking about, but you're still having drift issues because more than one TC gen is in use.

Subject:RE: Advice Please - Multitrack Recording and DV

Reply by: farss

Date:5/7/2004 6:27:33 PM

There are some audio recorders that'll accept external TC input or you can record linear TC to an audio track. But you'd need a way to convert the TC on the fwire out of the camera to linear TC and the recorders that take TC in seem to cost big time. I've seen a brochure on one that records 8 tracks to DVD media and another to HD but they were very expensive.