miniDV to miniDV Copying - is it lossless?

[sparky]

I have numerous miniDV tapes with only a few minutes recorded which I would like to compile onto one tape to archive.

I have two miniDV camcorders one of which can record from the i-link/DV port.

If I link the two camcorders together is the recorded copy the same quality as the original or not?

All the tapes have been edited to DVD with never more than 1h 15min on a DVD for best quality but I know this is compressed format. Hence I keep all originals should I want to edit again or convert to a different format in the future, assuming of course I still have a working miniDV camcorder to play them. While the tapes will deteriorate however carefully stored I think in say 25 years still having a working camcorder will be the bigger problem.

[Peter]

Not sure, I've just spent a fair chunk of time copying all my dv tapes to my computer, it takes a lot of storage, but it's a digital backup, and everything is ready to use. I too was worried about the lack of a device to read tapes in the coming years, in fact my dv camcorder gave up the ghost towards the end of my transfer spree, and I had to borrow one to finish it off.

A 1hr dv tape takes around 13gb on the computer for me.

[jimslip]

Any duplication from a tape machine to another will result in a loss. If you connect firewire to firewire (ILink) this loss will be minimal.

[sparky]

Peter,
What format do you convert / save to on your computer to keep the quality?
At 13GB per hour a 500GB hard drive would hold around 35 hours.
I would use normal 3.5" ones rather than 2.5" laptop/portable as lower data density. If run up occasionally my thought is the data should be safe for at least 10 years.

[Peter]

I'm using Final Cut Pro X, and that had a 'camera archive' feature, which basically makes a digital copy of your tape. If I was doing it manually, I'd just export it as a quicktime file, full sized and uncompressed. I don't know how to do it on non-macs, I'm afraid.

I have everything stored on a 1tb drive, which cost about ?44 quid at the time, and of course I still have the tapes as back up.

[milton]

Copying minidv to minidv by firewire to firewire is lossless provided there are no errors.

Also, from firewire to hdd then back to firewire is also lossless provided that there is no editing/rendering in between.

Copying digital content from one medium to another via a direct data link is lossless. That's why the entertainment industry hate the technology which enables it!

I.

[jimslip]

You are forgetting losses involved in the tape mechanisms between the machines. I used to make Firewire copies accross 2 studio decks and I could swear I'd see a tad more noise in the picture of the copy. Its all academic in the end, I'm sure the copies will be fine.

[milton]

The noise you see must be analogue noise in the player/display device. In a digital data stream the numbers are either right or wrong. If they are wrong they are usually corrected by redundancy algorithms; if they aren't corrected you have a "drop-out" resulting in a stall, blocks, stripes or a screen full of trash 'til the next key frame.

Its an all or nowt system.

[sparky]

Thanks for the various comments about miniDV to miniDV vis firewire/i-link - my understanding was that it was lossless apart from any tape dropout so theoretically could be done 100 times with no loss.

[jimslip]

Yes I agree about it being lossless in terns of Bit to bit, but I wonder if the analogue devices are able to introduce noise in between the binary information. This is some years ago, but I'd swear the more you copied, the worse the copies got even in Firewire. Obviously these days we copy hard disc to hard disc and there is never any apparent loss.