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-   -   Mosaic/pixel distortion via XL1 (https://www.dvinfo.net/forum/canon-xl1s-xl1-watchdog/105993-mosaic-pixel-distortion-via-xl1.html)

Eric Neal October 19th, 2007 04:52 AM

Mosaic/pixel distortion via XL1
 
Hi all,

My very first post, wow. And it's a Rubik's Cube. I'm sure I'm going to get some very disappointing answers on this, but I have to ask. I have several tapes I'm trying to capture from with some horrid distortion (you know that blocky/pixelated/mosaic look?). My XL1 has misaligned heads -- found that out the hard way -- so I've been using/trying other cameras for playback, one of them a little Canon Alura, but the noise is persistent, so I'm assuming the distortion is on the tapes themselves. I know there are places out there that claim to remove these glitches and salvage your footage, so I'm wondering if anyone knows of a technique to fix this problem.

Here's the puzzling thing: while I was shooting some of this recent footage, knowing that the heads are out of whack, between takes I would immediately play back what I just shot...and it looked fine and dandy! (In fact, I recently shot a whole field hocket match that's still perfectly fine.) Few hours later, I get home, play the tapes again and -- ARGH! The distortion magically happens. Have to keep telling myself "I love my camera...won't destroy it..."

Another mind-bender: even with the misaligned heads, some tapes shot on my XL1 are playing back fine. Whassup with that? Help, please? I don't have much hair left.

Don Palomaki October 19th, 2007 07:05 AM

Any tape should playback OK on the machine that recorded the tape, at least immediately after recording. It may not playback on the machine if the head alignment/tape path has changed since the recording was made. The change could be the result of aging, realignment, or damage.

Also, dirty heads can cause tape read errors that will result in the mosaic effect on the image. Use of a cleaning tape can help if dirty heads is the cause.

Lastly, there can be issues if the camcorder is not in good maintenance, and this means both the mechanical parts, and the internal electronics; e.g., is the record current tot he head correct, and are the tracking control circuit operating correctly.

Eric Neal October 19th, 2007 01:22 PM

Thanks for the answers, Don. I thought the tapes would/should play back fine, but they won't. Any ideas on what's happening there? Sounds like your suggestion #3 about the tracking controls, etc.

Also, I've tried a cleaning tape (bought an expensive Canon brand just to play it safe), which did nada.

Don Palomaki October 19th, 2007 02:32 PM

About I can suggest at the moment is to try different playback machines, you may get lucky and find one that will play the tapes in question, and:

In some cases you can obtain an usable analog output when digital capture fails, but that may not answer the problem you have.

If the problem is at the exact same place on the tapes on question on all playback system you try, it most likely a problem with the information recorded to that tape. However, if it drifts around a bit, it may be a problem with the physical tape itself, and not the information recorded to the tape, meaning not totally the camcorder's fault - you may have an out-of-spec tape.

If the noise location is drifting a bit in different playbacks, you may be able to capture the footage in pieces, and incrementally put it back together from the good pieces.

In any case, have your camcorder serviced as soon as feasible, but not before you decide there is no longer any chance of using it to playback the questionable tapes, and be aware that once aligned (if that was the problem) it might not play tapes it recorded when it was out of alignment. Thus it would be prudent to dub any other tapes you want to archive that may be a problem

Eric Neal October 21st, 2007 10:43 PM

Hi Don,

Sorry for the delayed response here. Thanks again for the suggestions, all very helpful. (And I'll be shipping my camera out tomorrow.)


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