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Sony HVR-A1 and HDR-HC Series
Sony's latest single-CMOS additions to their HDV camcorder line.


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Old September 26th, 2006, 11:45 AM   #1
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How long do tapes last?

What I mean is, how many times can you record over a good sony HDV tape before you start losing picture quality? I burn directly to DVD after a recording so I don't really need to save the tape forever and hate to spend $10-$15 for just one recording.
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Old September 26th, 2006, 12:04 PM   #2
 
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1. You should *never* reuse tape for anything of critical value.
2. Quality doesn't suffer, the risk of dropouts increases exponentially. "Quality" can't be lost; the information is merely a series of 1's and 0's. However, those 1's and 0's can drop down a black hole, causing a dropout. Consider it akin to a bad sector on a hard drive.
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Old September 26th, 2006, 03:01 PM   #3
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I doubt about the exponential growth of dropouts when reusing DV tapes. It's indeed about 0's and 1's but the head's output levels are high enough, (when the video heads are still in good shape and clean) for the slicer circuits to cope with signal level reduction as a result of frequent use. I think that after a number of reuses, the number being depending on the tape brand and the videoheads condition, a treshold is reached which will start severe dropouts. I am not aware of tests that show extra dropouts before 10 playback sessions, and playback is far more affecting the output signal level then 10 record/playback sessions.
Dropouts in HDV (long GOP MPEG2) have terrible effects. They kill the signal for almost half a second for each unrecoverable dropout.
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Old September 26th, 2006, 03:05 PM   #4
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How long do tapes last?

Since we are on the subject and I apologize for the hijack but I thought this might be closely related..
I have been using standard DV tapes shooting in HDV. When I capture I just downconvert. My idea was not to reuse HDV tapes and I wanted to shoot in HDV for future use. I don't see any qaulity loss by using the SD tapes. Am I missing something or are HDV tapes well lubricated SD tapes in disquise.
I've only started doing this, any reasons why this might come back to bite me.


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Old September 26th, 2006, 03:19 PM   #5
 
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Quote:
Originally Posted by Andre De Clercq
I doubt about the exponential growth of dropouts when reusing DV tapes. It's indeed about 0's and 1's but the head's output levels are high enough, (when the video heads are still in good shape and clean) for the slicer circuits to cope with signal level reduction as a result of frequent use. I think that after a number of reuses, the number being depending on the tape brand and the videoheads condition, a treshold is reached which will start severe dropouts. I am not aware of tests that show extra dropouts before 10 playback sessions, and playback is far more affecting the output signal level then 10 record/playback sessions.
Dropouts in HDV (long GOP MPEG2) have terrible effects. They kill the signal for almost half a second for each unrecoverable dropout.
it's not a question of HDV vs SD/DV.
Do a search around the web, you'll likely find an article on a website I moderated many years ago, where we were able to demonstrate dropouts in DV after an average of 5 reuses. Dropouts on an Iframe of HDV are indeed more heinous than a single or double frame dropout in DV, so you run a higher risk with reuse of tapes with HDV. Granted, tape has changed a bit over the past 6 years when we did the shootout/tests, but tape is tape when it comes to metal particles adhered to plastic strips.
Frankly, I can't see any reason for reusing tape on any for-pay shoot, and the client deserves the reassurance that if they're paying for your talent, that talent should also include new tape. It's not just an issue of DV or HDV either. You'll rarely find anyone reusing HDCAM tape either. It's an issue of tape integrity. The more you rewind, fast forward, play....the more degradation occurs on the tape. It's not rocket science, it's basic knowledge of how tape works, and how it has essentially always worked even going back to the days of wax cylinders, phenolic LP's, wire recorders, vinyl, etc. This is why platters are better.
All that said, if you're shooting your son/daughter playing soccer, dumping it into the computer, and a dropout isn't gonna leave you redfaced in front of the client, then reusing tapes is probably a good idea.
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Old September 26th, 2006, 04:24 PM   #6
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Agree, but tape formulations are good these days... I never reuse tapes although I have a Sony Exelence tape which I have been using over and over again for test purposes, and still not a single dropout.
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Old September 26th, 2006, 07:50 PM   #7
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Quote:
Originally Posted by Lou Trottier
I don't see any qaulity loss by using the SD tapes. Am I missing something or are HDV tapes well lubricated SD tapes in disquise.
Lou - the reason you don't see any quality loss is because there IS none. You're right - HDV tapes are simply MiniDv tapes, but maybe built to fner tolerances and have double-layer Metal Evaparoted tapes. all this is to achieve a lower incidence of tape dropouts (errors) as these are really quite dramatic in HDV. But the quality of footage is identical - it's all MiniDV 'spec'.
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Old September 29th, 2006, 02:32 PM   #8
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I'm one who differs in my views. I'd never dream of taking a brand new untested piece of kit and using it for the first time for a paying client. You pay a few dollars for a mass produced tape and you hope that this one will be perfect.

Well, the factories are pumping out tape by the million, for amazingly cheap prices. Eash MiniDV tape contains 28 parts and even if the factories produce 99.99% of tapes that are perfect, that means a vast number hit the shelves that are imperfect in some way.

Once I've used a tape and downloaded its contents to my PC's HD, then - and only then - can I say it's perfect. So yes, I reuse tape frequently, safe in the knowledge that I've tested it as much as I've tested the Z1.

tom.
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