OT Audio Capture Issue

murphy wrote on 12/8/2007, 11:39 PM
I am unable to capture the audio portion of some mini dv tapes.

I have 14 tapes and one tape will allow me to capture both audio and video. I'm using a panasonic pv gs83 connected via firewire, tried it on 2 different pcs I've checked all the connections countless times. Tapes that are recorded with panasonic transfer the audio no problem

These tapes were originally captured about 5 years ago at an event on 2 sony pd 170's and a cannon xl1.

I can hear the audio coming thru the camera but it doesen't register on the time line in Vegas 8, There is an audio track created but no sound comes from it. When I try capturing the tape that does transfer the audio I can hear the audio both coming thru the camers speaker and thru the head phones connected to the sound card on the pc

The tapes that dont capture the audio I hear it coming thru the cameras speaker but not thru the head phones

I can't figure this out and was hoping someone here may have some suggestions If you know of any work arounds that will allow me to capture the audio seperatly and then combine with the video track please let me know
I'm thinking that most of the tapes were originally captured in 16 Bit and that this cam for some reason won't allow the 16 bit audio to capture although it does allow for 16 bit recording.

Thanks for taking a look

Comments

farss wrote on 12/9/2007, 12:18 AM
All DV cameras do 16bit 48KHz audio, that's the DV spec.

Simple workaround and I've done this several times.
Capture the video and however much audio you can get.
Then take the audio outputs from the camera into a good sound card. Record that at 16/48K using Vegas. Line up the recorded audio track with whatever remains of the DV audio and vision. Mute DV audio track and render to a new file. Possibly record that to a new tape for safety.
That's it.
Bob.
murphy wrote on 12/9/2007, 8:08 AM
Thanks Bob for your help.
This camera does not have rca cables out but does have usb I tried using the usb out and although the camera is recognized I not sure how to capture the audio thru the usb port in vegas.
It seems like that would be the way to go though
Any ideas about which software would do this?
Chienworks wrote on 12/9/2007, 8:11 AM
The USB port is usually used for either still images or highly compressed web-cam style video. I don't think you'll be able to get the audio that way, at least not anything you'd want to hear.

Surely the camcorder at least has a headphone jack. Use that instead of RCA outputs.
Tim L wrote on 12/9/2007, 8:41 AM
Maybe you're overlooking it, but I'm sure this camcorder must have RCA outputs so that you can connect to a regular TV for viewing. I didn't find specifics on the GS83, but the similar model(?) GS85 apparently has an A/V output on the right side near the front (probably behind a cover). You probably have a cable that looks like a minijack connector on the end that plugs into the camcorder, and three RCA jacks (yellow, red, white) that plug into the back of a TV (unless the cable has an S-Video connector in place of the Yellow RCA). Audio is on the Red and White RCA jacks.

Still, though, not having sound is puzzling -- especially if you hear it playing on the camera. Did you use the Vegas VidCap capture program? or some other capture option?

If you play the "no audio" AVI files in Windows Media Player do you get the audio? If so, you might have captured a Type 1 AVI file vs. the Type 2 AVI format that Vegas requires. If this is the case, you can either recapture with Vegas VidCap to assure you get a Type 2 AVI, or you can find a Type1 to Type2 converter program on the web to convert the files you already have.

Tim L
farss wrote on 12/9/2007, 1:41 PM
This problem is not uncommon, I've had much the same issue several times.
Trying different computers will not solve the problem and it has nothing to do with how the video is being captured and everything to do with DV and how cameras and VCRs play it out over firewire.

The best approach would be to try a different device, start with a DSR-11, if that doesn't fix the problem we go for a DSR 45, if that fails as well then find someone with a DSR 2000.

That tapes from a Canon camera exhibit this problem is not unusual, they are notorious for guide alignment problems however as the same thing is happening with old tapes from a PD150 it's possible the camera currently being used as a VCR is slightly out of alignment.
The other possibility is as these tapes are old, they may not have been stored correctly.

Bob.
Chienworks wrote on 12/9/2007, 4:04 PM
The alignment idea puzzles me. Analog decks record separate audio and video tracks on the tape. DV has everything mixed together as a single data stream. There aren't any audio tracks or audio heads on DV tape. So, if the video is being read, the audio is too. It must be something in the camcorder's firmware that's misformatting the audio and either not sending it down the firewire or making the video capture program think it's not there.
farss wrote on 12/9/2007, 4:55 PM
As someone cursed with a brain that's wired to want to know how other things are wired I wish I had a better explaination for what I've observed too. A couple of things to throw into the mix.
Contrary to popular belief the transfer of data from the DV tape to computer is not strictly a bit transfer. Audio has to be synced and there's quite a bit of error correction as well. When things start to go wrong it's the audio that seems to go first although not many notice it until it gets really bad.
For some reason the DV camcorders and VCRs do a better job of putting that data back together again for their analogue ports than they do for their firewire ports. It's quite possible that VidCap doesn't do as much error correction as it might either. I have recently had one problem tape that faired better using SCLive than VidCap but that's not scientific. Simply running a tape over the heads again can help get the data off during the next pass. On some problem tapes I've done multiple captures and found the problem areas shifted enough to patch things back togther.
How does this relate to guide alignemnt I'm not really certain. I'd imagine if the heads are slightly mistracking then there's a higher error rate and if there's less error correction on the audio then it goes.

Another wierd example. A few years ago I shot something on a PD250. During capture the TC kept coming and going, no dramas thanks to Vegas. Sent the camera off to Sony and they 'fixed' it and sent it back. We tested it, same problme. Perfect pictures and audio but playing the tapes back on a DSR-11 TC was there around 50% of the time. Back to Sony it goes. We tried the tape on their DSR 20 and TC is perfect. So they dragged out a DSR-11 and boom, TC is flaky. It got fixed in the end but no one including the service tech had an explaination for the behaviour he'd seen. From memory all he did to fix it was adjust the tape guides in the camera. It was in spec originally but just at one end of the spec.

Bob.