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Dick Nelson
03-25-2003, 08:33 PM
We have only been using VT[2] for a few days. Today we ran into a new problem. A captured audio/video clip played back slightly out of sync. The clip was captured from DV tape. We have also had this problem on occasion capturing clips in Apple Final Cut, so it's not a problem unique to the Toaster. But is it common, and is there a fix?

SBowie
03-25-2003, 09:28 PM
How long was the clip, and how did you capture it? Did you capture it from within the Toaster, or externally using some other app? Was it captured as native DV, or as an RTV, or something else? Did you capture Program Out or Main In?

mgutman
03-26-2003, 05:58 AM
I think you will find that it is out of sync by exactly 1 second. I think this is because of the default 1 second "in" point (which can be set as desired in preferences).
hth, Mike

SBowie
03-26-2003, 10:36 AM
Hmmm ... maybe, but I'm not sure anyone would refer to a 1 second delay as a "slight" sync error.

Dick Nelson
03-26-2003, 10:49 AM
How long was the clip, and how did you capture it? Did you capture it from within the Toaster, or externally using some other app? Was it captured as native DV, or as an RTV, or something else? Did you capture Program Out or Main In?

The file was captured within Toaster as an RTV file with Program Out.

Dick Nelson
03-26-2003, 10:54 AM
Re: the one-second offset. Preferences already was set to "No offset." Plus, we captured several other clips with everything set the same way and didn't have the problem. I have since captured another clips which is in sync at the beginning, but not at the end. I can't tell where it gets out of sync because there's voice-over in the middle. At the beginning, with the talent on camera the sound is in sync. Then it goes to voice-over. Then it comes back to talent on camera and it's out of sync.

SBowie
03-26-2003, 02:15 PM
Originally posted by Dick Nelson
The file was captured within Toaster as an RTV file with Program Out. OK, that can be a factor, depending on...

Originally posted by Dick Nelson
I have since captured another clips which is in sync at the beginning, but not at the end. I can't tell where it gets out of sync because there's voice-over in the middle. At the beginning, with the talent on camera the sound is in sync. Then it goes to voice-over. Then it comes back to talent on camera and it's out of sync. So this latter clip has been pre-edited somewhere along the way, or how did the voice-over get added? Again, apart from that, length can be a factor...

TTBOMK, Recording Program Out as you are takes advantage of the Toasters 'TBC' function, and on a very long capture it is possible to get a little (normally very trivial) sync drift. Recording Main Out bypasses this, but can result in the occasional glitched frame due to timing errors from the source.

In any case, sidestepping it when it occurs might simply be a matter of splitting the RTV and WAVE and doing a little nudging? (If your issue doesn't involve long clips, I'd love to hear more about it.)

Dick Nelson
03-26-2003, 08:10 PM
As with all the clips, this one was originally edited in Apple Final Cut, printed to a DV tape, then captured from that tape into the Toaster via regular audio and video inputs (not firewire). The audio is not out of sync on the tape. None of the clips exceed one minute in length. Except for the one clip, all the problem clips have been consistently out of sync from beginning to end. Bear in mind that we have also captured a few clips, using exactly the same method described above, with no problem.

SBowie
03-26-2003, 08:23 PM
Weirder and weirder...

Could you describe your system setup for us?

Dick Nelson
03-26-2003, 08:46 PM
What do you need to know?

Gordon
03-26-2003, 09:39 PM
Hi Dick;
Problems like this almost always come down to a break in the control track on tape. Often captured video from tape includes an edit point, generally because there wasn't enough pre-roll in the clip on the DV tape. This edit point will have a break in the control track and this confuses every analog capture non-linear editor.

The best thing to do is to transfer the DV clip(s) via firewire into the Toaster machine instead of doing an analog capture. Decision Maker DV and Scenalyzer are a couple good programs for DV transfer especially when coupled with the MainConcept DV codec. (Choosing Type2 for DV format will use the Main Concept DV codec when it is installed.)

http://www.vionline.com/
http://www.scenalyzer.com/main.html
http://www.mainconcept.com/codecs.shtml

SBowie
03-27-2003, 06:35 AM
A control track break crossed my mind, too Gordon -- but I'm not clear on how that could skew timing on an analog capture. I'd have expected any timing errors to be synchronous, affecting both A and V. If this is the cause, though, would running the source through a TBC perhaps resolve the issue?

Dick Nelson
03-27-2003, 07:28 AM
I'm not sure what you mean by a control track break. I know what that is, of course, but I'm not clear what would cause one in this case. The TAPE itself does not have any edits in it. There are, of course, edits made in Final Cut.

So that I'm clear, here's our procedure. Students edit their stories on Final Cut. They then "Print to Video" (Final Cut terminology for recording the finished product on DV tape). This tape is then taken to the Toaster where it is captured via audio-video inputs from a DV playback deck. It's then played back from a DDR during the newscast. (We also have the capability of recording the story on VHS and capturing in the Toaster from that, and I will try that today to see if we have the same problem. Obviously I don't want to make that our standard practice because of VHS quality loss.)

slacker
03-27-2003, 08:43 AM
One thing we've found that may or may not help you is that Canon equipment (specifically the xl- and gl- series cameras) has been known to create weird sync issues. I've found this to be the case in our old Final Cut suite (circa 1 B.T. - before toaster :D ) and in our linear room when people send in tapes shot on canon cameras (I've not captured any dv or canon-filmed footage on the toaster yet). If, as you mentioned in your first post, it is a problem on multiple NLEs, your cameras/decks would be the first place I'd look.

Regards,

Joel Slack
Media Department, New Life Christian Fellowship

Gordon
03-27-2003, 09:43 AM
Steve;
I'm not even sure using a direct DV copy would work let alone a full TBC! (But DV transfer would be the first thing I would try. Especially since you can download the free trial versions of the software I listed for a test to see if it solves the problem.)

Dick;
You should test to see if this problem is related to just some DV clips from FCP or if he has the same problem on some clips that have never touched FCP or any other editor. Could be a problem with the record/playback hardware or with FCP software or could be a problem with the way FCP 'prints to tape'. You may also want to try changing the DV type used by FCP between Type1 and Type2.

Finally, you may want to make sure you pad the head and tail of the clips to be re-captured in ToasterEdit with 10 seconds of black just to make sure that you have enough time to start and stop the recording in TED well within the 'In' and 'Out' points of the FCP edit.

Gordon
03-27-2003, 09:46 AM
It could also be a problem with just that tape. These DV tapes are NOT robust and don't stand up to editing.

Dick Nelson
03-27-2003, 07:43 PM
We think we have solved the problem. Turns out that it seems related to the tape deck we were using.

We have two DV decks hooked up to the Toaster. They're both Sonys, but different models. I had been doing all the capturing on one of the decks. When I switched to the other one, the problem disappeared. I haven't been able yet to figure out why this might be. Both are connected to the Toaster in the same way. Is there some configuration on the individual inputs that might be different?

Also, it became obvious that on the same deck we had the audio problem with we were getting a glitch at the beginning of the first shot of video. I'm thinking that the two things are related.

SBowie
03-28-2003, 05:32 AM
Originally posted by Dick Nelson

Also, it became obvious that on the same deck we had the audio problem with we were getting a glitch at the beginning of the first shot of video. I'm thinking that the two things are related. Could be. I have seen a somewhat similar issue with a different NLE system using DV from a DHR1000 when there was a mismatch between 12 and 16bit audio on the tape and the DHR.

The issue was barely noticeable on analog output from the deck, but caused constant problems on DV out. Sony spent a long time looking for the trouble without finding it, and it had plagued the user for months. I was fortunate enough to stumble on it by chance after about 20 minutes experimentation. The deck was showing the 16bit light when playing the tape, which would seem to imply auto-detection of audio modes was working, but the problem disappeared when I manually set it to 16 bit in the menu. (What reminded me of this is when you mentioned the other deck did not seem to exhibit the issue. My clients TRV-900 did no have any problems playing his tapes, only the DHR1000.)