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View Full Version : MiniDV tapes - how many runs?




MrSmith
Sep 3, 2005, 09:23 PM
Hi all

I have some mini DV tapes that I shot on 12 bit and, for sound sync reasons, I'm running them back to my camcorder set to 16 bit, and then pulling them back to iMovie.

I've done this for a few movies now and it's fine. Today I did this for a movie, played it back to the camcorder, then rewound the tape in the camcorder and sent ANOTHER movie to it; i.e. to the SAME tape. When I sent this second movie back to iMovie I noticed that the quality was a lot worse than the others I've done (especially noticeable on stills). The movies were shot during the same holiday, on the same camera, etc.

This is the first time I've re-used a tape. My question is, despite being digital, is a miniDV's quality reduced if it's re-used?

Thanks for any experience I can learn from.



leftbanke7
Sep 4, 2005, 01:37 AM
Hi all

I have some mini DV tapes that I shot on 12 bit and, for sound sync reasons, I'm running them back to my camcorder set to 16 bit, and then pulling them back to iMovie.

I've done this for a few movies now and it's fine. Today I did this for a movie, played it back to the camcorder, then rewound the tape in the camcorder and sent ANOTHER movie to it; i.e. to the SAME tape. When I sent this second movie back to iMovie I noticed that the quality was a lot worse than the others I've done (especially noticeable on stills). The movies were shot during the same holiday, on the same camera, etc.

This is the first time I've re-used a tape. My question is, despite being digital, is a miniDV's quality reduced if it's re-used?

Thanks for any experience I can learn from.

If I am thinking correctly (and I might not be) I think I remember my video editing professor saying something about how you get about 1000 go arounds with DV tapes. I wouldn't quote me (or her) on this but that's what keeps running through my mind.

LethalWolfe
Sep 4, 2005, 04:42 AM
The more you use a tape the more prone you are to drop outs and other errors. But the image shouldn't "go soft" like if you use an analog tape too much (assuming you are always using firewire and not the analog I/O's). It's digital so either the image is there or it's not.

In college I used DV tapes over and over again, but as a pro I'd never re-use a DV tape. They are so cheap it's not worth the risk in my line of work.


Lethal

MrSmith
Sep 4, 2005, 07:35 AM
Yes, being digital they shouldn't wither. As you say, the information is either present or it isn't. Unless the tape becomes unable to record that information. But that's not going to happen after one use.

Actually, the images didn't go soft. They became jagged.

Beats me, then. I'll just try again. But the quality was definitely cr@p on the stills.

Thanks guys.

JeDiBoYTJ
Sep 4, 2005, 08:32 AM
the best thing to do when wanting to rerecord over a tape is to purchase a Tape Eraser, which is just simply a big magnet that erases VHS and DV tapes and such. If you do it right, it completely erases the tape and it works like brand new :)

2jaded2care
Sep 12, 2005, 03:16 PM
the best thing to do when wanting to rerecord over a tape is to purchase a Tape Eraser, which is just simply a big magnet that erases VHS and DV tapes and such. If you do it right, it completely erases the tape and it works like brand new :)

I used a degausser in college, but to tell you the truth it makes me nervous to have any strong magnetic field anywhere near the tapes. Mistakes can happen. (Plus, they always told us to remove any mechanical wristwatches before using it.) I usually just black the tapes I intend to re-use.

You really do need to black the tapes or degauss them, because I've had it happen where, if you just record over previous signal, if there's a glitch sometimes you can see blocks of the previously-recorded video on top of your newly-recorded video. At least if the tape's black (or blank), any glitches appear only as black blocks, not part of an old video.

Personally, if it's important, I wouldn't re-use a tape if I could help it. Even when I do re-use tapes, I don't re-use them more than 5 or 6 times.

Also try not to switch brands of tape, but if you have to, use a head cleaner first.

evil_santa
Sep 12, 2005, 04:19 PM
This is what DV dropout looks like, when either the tape is worn or the video heads are worn / clogged
http://homepage.mac.com/editbox/images/dropout.jpg

And this is what 'soft' digital looks like, caused by re-encoding. this is part of a image that was on DV>mpeg>Jpeg. all the fine detail in the tree is lost & the sharp edges have gone, as has fine detail.
http://homepage.mac.com/editbox/images/soft_image.jpg

ammon
Sep 24, 2005, 06:03 PM
After working for a production studio I adopted the philosophy of using a tape only once. Even though it is digital and they claim you can use it multiple times, it is better practice to purchase another tape.

bigandy
Dec 29, 2005, 09:08 AM
agreed. i never use tapes more than once, and always have a fresh supply. i find it doubly important on my HDV camera - try and use a tape in that for a second time and you're.... well, just don't.

revenuee
Dec 29, 2005, 09:18 AM
Even though the information is stored digitally the tape surface is still subject to oxidization and degrade your tape

HIGH grade Mini DV vs consumer level DV tapes will last longer BUT are still subject to it.

BEST thing to do is use a new tape if optimal quality is a concern.

i like to keep the raw recordings archived anyway, never know when you might want some source footage <-- BUT that might just be me