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Canon XH Series HDV Camcorders
Canon XH G1S / G1 (with SDI), Canon XH A1S / A1 (without SDI).


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Old December 10th, 2008, 11:49 AM   #1
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9 Second gaps

Here's my story.

I used Panasonic 63MQ tapes and never had a problem.

Then last April the show I was going to record had 80 minute acts. So I tried the Panasonic 83PQ tapes. Before I used them, I did run the Sony tape cleaner through my A1.

When I captured the recording into FCP 6, I would get a dropped sections of about 9 seconds. It was consistent, if I tried again. It didn't happen too often, but enough to be annoying. Zero to three 9 second drops per tape. Since I had recorded multiple days, I was covered for all the scenes and really didn't hurt my final output except for having to work around all those gaps.

I cleaned the heads again and switched back to the 63MQ tapes, but the problem of the 9 second drops is still happening.

It seems that I lose a few "L-Gop" at a time. I'm shooting 60i.

Any recommendations to fix this? Get the heads professionally cleaned?

Thanks,
Howard
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Old December 10th, 2008, 12:34 PM   #2
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Are you sure it's a problem with the camera? This happens a lot to me and it's usually the software I am editing with. Dropouts are pretty common when digitizing even if there is nothing wrong with the actual tape or camera, usually timecode related (in which case just digitize without timecode) or the computer doesn't have enough memory to keep up with the video. Does it happen if you try digitizing from a different deck?

Or maybe something happened and your computer just does not like the camera anymore. I know it sounds stupid, but there was this one freelance camera guy at work who all of the sudden I could not digitize his tapes anymore from the deck I used because the deck just stopped playing stuff shot with his camera properly (lots of dropouts) and I had to route everything shot with his camera from a deck in another room in order to use any of it. Now that was with an Avid, but you never know, maybe that's what happened, though I highly doubt it.
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Old December 10th, 2008, 12:42 PM   #3
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Hi Howard,

One option is to make a firewire dub of the tape and capture the copy. If it is a problem with the tape this should fix it...


Quote:
Originally Posted by Howard Wilczynski View Post
Here's my story.

I used Panasonic 63MQ tapes and never had a problem.

Then last April the show I was going to record had 80 minute acts. So I tried the Panasonic 83PQ tapes. Before I used them, I did run the Sony tape cleaner through my A1.

When I captured the recording into FCP 6, I would get a dropped sections of about 9 seconds. It was consistent, if I tried again. It didn't happen too often, but enough to be annoying. Zero to three 9 second drops per tape. Since I had recorded multiple days, I was covered for all the scenes and really didn't hurt my final output except for having to work around all those gaps.

I cleaned the heads again and switched back to the 63MQ tapes, but the problem of the 9 second drops is still happening.

It seems that I lose a few "L-Gop" at a time. I'm shooting 60i.

Any recommendations to fix this? Get the heads professionally cleaned?

Thanks,
Howard
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Old December 10th, 2008, 01:15 PM   #4
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It's silly but I didn't even think of copying the tape.

I think the first thing I do is to watch the tape through the camera at the point it is "bad" and see if it really is the tape or the camera or FCP.

What makes me think it is the tape is that is it absolutely reproducable at exactly the same timecode if I try again.

I have a Mac Pro with quad processors and 7 gigs of memory, capturing to a 1 terrabyte raid device, so I'm pretty sure it is not the computer.
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Old December 10th, 2008, 06:07 PM   #5
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I think it might be a good idea to check the tape on another camera first if you have one available. There have been plenty of times where I pull my hair out checking a camera or deck to find out why a tape won't play right and then I just play the tape in another device and it plays perfectly even if the hit keeps on happening at the same location. Like I said before, sometimes a tape just won't like what it's being played on.
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Old December 10th, 2008, 09:37 PM   #6
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Quote:
Originally Posted by Daniel Fessak View Post
Dropouts are pretty common when digitizing ....
I've not found this to be true, and I've been playing in this patch since Skippy was a duck.

9 seconds is a bit long for a dropout. Mine are generally about 3 seconds long and are repeatable. I haven't tried capturing the same tape with another camera mostly because I didn't think it would make a difference if the problem was with the tape.

Your longer dropouts may indicate a different problem than normal tape glitches although I haven't a clue as to what.
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Old December 10th, 2008, 11:18 PM   #7
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I tried one of the tapes in a different camera and it still happened at the same point in the capture. I watched the camera display and the picture freezes for about 4 seconds, then continues.

I said 9 seconds because that is the time code difference, so maybe it isn't really 9 seconds, but 4 and the time code gets messed up too.

Howard
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Old December 11th, 2008, 01:37 AM   #8
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Hi

Try to do a record over the bad part of the tape, where you have the dropout. Then recapture the new recording and see if you get a dropout again on the same location. If that's the case there is something wrong with the tape, if not there was probably some kind of glitch during the first recording session.


Regards,

/Bo
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Old December 11th, 2008, 08:13 AM   #9
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Yes, I think I will try that, to record over that spot. But first I need to finish my current project in case I need any of the data around that spot.

Good idea.

Howard
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Old December 11th, 2008, 08:55 AM   #10
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I actually had this happen to me a few days ago. I haven't shot much with the camera, about 25-30 tapes or so, but I digitized a wedding ceremony and there was a seven second drop.

I'm using FCP 5.1.4, and Sony tapes. I could go back and recapture this missing portion, but didn't understand why the drop happened in the first place, if I could go back and get it. Maybe there was some dust or something that got in there, and then was gone.

Please post here if you find something out.
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Old December 11th, 2008, 07:03 PM   #11
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What would be interesting to see is some sort of white paper on the causes of HDV dropouts. In addition to minimizing the head scratching going on around here, it would be helpful to know what steps we could take to eliminate the dreaded dropout.

Yeah, it would take a lot of work to do all the testing and even then there would be no way to know how accurate the data might be. To paraphrase (probably badly) the Heisenberg principle, the mere act of observing a test will effect its outcome.

Still, it would be good information to have.
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Old December 14th, 2008, 11:25 PM   #12
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Add me to the list. The 80 min Panasonics (AY-DVM83PQ) are very prone to dropouts. The 60 min tapes have even dropped out in 4x3 SD mode! My previous cameras never had so many dropouts. I have decided to go solid-state and buy the Sony HVR-MRC1K CF Recorder in January.
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Old January 25th, 2009, 11:50 PM   #13
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Sorry I did not get to try the gap problem sooner.

I was going to see what happend if I recorded over a bad spot.
But my camera seems to have mostly stopped working.

See my new thread:
http://www.dvinfo.net/conf/canon-xh-...o-nothing.html

However, the camera still does playback and when I checked the first "gaped" scene, it played ok, no skips. When I played the second one, the gap was still there and when I tried to record, my "new" problem showed up.

So I guess the camera goes off to Canon and I will report on the gap issue when I get it back. I think I will have them clean the heads too.
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