DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   General HD (720 / 1080) Acquisition (https://www.dvinfo.net/forum/general-hd-720-1080-acquisition/)
-   -   Backing up HD need to dub to HD tape? (https://www.dvinfo.net/forum/general-hd-720-1080-acquisition/91796-backing-up-hd-need-dub-hd-tape.html)

Kevin Carter April 18th, 2007 11:07 AM

Backing up HD need to dub to HD tape?
 
I'm making HD tapes, mini DV for small projects such as wedding and other small consumer stuff. not life or death, but here is question:

For convenicne, it's nice to back up mini DV (even HD) to a DVD-R, via camcorder to home unit DVD recorder.
But this DVD-R back up, will not be true HD (high def), or HD at all correct?

And if this is so, is it correct that only way to get a true HD back up is to do the more cumbersome and expensive deck to deck, tape to tape back up in real time?

thanks

Dick Nelson April 18th, 2007 08:52 PM

If I understand you, you want to back up edited projects or clips that started as HDV footage, yes? You can save the raw captured HDV data files to a data DVD-R and preserve it as HD, but you won't be able to stick it into a home player and view it.

Or, you can convert the HDV to an MPEG file and make a regular DVD for viewing, but it then will be standard definition.

Peter Ferling April 18th, 2007 08:57 PM

The other affordable alternative to an expensive deck is a cheap hard drive and a cool, dry place to store it.

Marcus Marchesseault April 19th, 2007 12:00 AM

Why are you backing up the footage? Are you just keeping a copy of the edited footage for future use? Are you trying to keep the footage in a format that can be re-edited? Why don't you want to use DVD-R since the data is just the same as having it on a hard drive? Again, why do you need to backup a tape, what is your purpose? The answers vary depending on your purpose.

Steven Gotz April 19th, 2007 07:02 AM

Just to get the answer in this thread, the only way to back up a HDV tape losslessly is to do the more cumbersome and expensive deck to deck, tape to tape back up in real time.

Once the HDV is captured, putting it back to tape is a little lossy.

Most of us keep the original tape, and also back up the material we used on an external hard drive. No loss there.

One of the problems with the original post was that most of us would disagree with:

"it's nice to back up mini DV (even HD) to a DVD-R, via camcorder to home unit DVD recorder"

That method of backup is virtually useless because the resulting MPEG2 is not viable for further editing. It is only valuable for making copies of the DVD. At that point, you might as well keep copies of the DVD with menus that was sent to the customer in the first place.

Marcus Marchesseault April 19th, 2007 07:35 AM

"Once the HDV is captured, putting it back to tape is a little lossy."

How is that possible unless some sort of transcoding was done?

Steven Gotz April 19th, 2007 07:40 AM

I don't know of any programs that can take a native HDV file, make cuts, and then put it back to tape without reworking the 15 frame GOPs. Some programs are better than others, but all have some loss, as far as I know.

If anyone has proof otherwise, it would be interesting to see. But I know for sure that even programs that claim to edit native are not sending it back to tape untouched.

Ervin Farkas April 19th, 2007 10:19 AM

Steven, what you just said means that once you edit the tape, regardless of the format, there will be some loss. I agree with that, and that's true even in the case of standard definition DV, except maybe if the only editing you've done is straight cuts.

How about a camcorder to camcorder direct transfer (or back to the same camcorder without touching the footage) of HD footage? Let's say your tape is so valuable, you want to make sure you have a second copy and store it in a secure place. In this case there will be no loss, correct? Also, there should be no loss when transferring back to tape HDV footage where you edited in the native m2t format all you've done is straight cuts at the GOP boundary, right?

Thanks,

Steve Leverich April 19th, 2007 11:03 AM

"How about a camcorder to camcorder direct transfer (or back to the same camcorder without touching the footage) of HD footage? Let's say your tape is so valuable, you want to make sure you have a second copy and store it in a secure place."

Ervin, this is what I do with all tapes - I shoot industrial safety/training video, and I do firewire dubs to a second cam so I have two copies of the original material - I then further back these up to multiple hard drives once captured - this because there may be times when old footage is wanted by my clients to use in a newer (but still germaine) application. Tape to tape is the only way I'm aware of to maintain zero loss with high reliability factor.

I think your post (and the one following it) were deleted to keep a mis-communication from turning into a locked thread... Steve

Steven Gotz April 19th, 2007 02:15 PM

Ervin,

Well, with DV straight cuts you don't have any loss. They have not figured out how to do that with HDV as far as I know.

Dubbing valuable tapes makes a lot of sense. And for protection against physical loss, capturing and writing back to tape is not so bad that it is not worthwhile, it is just not as effective as tape-to-tape.

Kevin Carter April 19th, 2007 08:54 PM

Ok guys, thanks for info. To clearify, I just shot some HDV on Sony HD Camcorder which I have two of.

So I now hand over the original mini DV to an editor. If his house burns down, I want a backup that is lossless and a clone of the original.

A dub from camcorder 1 to the same exact camcorder 2 via Firewire should make a perfect clone, correct? (using same HD tape in real time)

I think I got my answer that going FW to a home deck would make a lower quality mpeg -- that's life, but that is cheaper way to go as these tapes run about $10 pop.

Hard drive is great, I use it for my photos, but DV footage, it would be absurd. How much hardrive space is need for an hour of unedted HD footage?

Steven Gotz April 20th, 2007 07:01 AM

Kevin,

Tape to tape, no loss. And yes, the tapes are expensive but they are the most reliable backups.

Unedited HDV is about the same as DV - under 13GB per hour. With the price of 250GB drives as low as they are, you can store around 20 hours of video on a drive costing under $100 - which is about half as much as tapes, and a lot easier to get your video from.

Kevin Carter April 20th, 2007 11:00 AM

Thanks Steve:
I will have some spare 500 GB drives soon:
1) I heard that HDV takes up much more hard drive space than standard Def, no? I thought if would be like double or triple.
2) HD mini DV, not under $10 still anywhere right? if that price point was like $3 of regular that would make decision easier.
3) How cumbersome is it transerfering to hard drive as opposed to dubbing deck to deck? (software wise I only own final cut express DV and Quick Time Pro)

Steven Gotz April 20th, 2007 12:46 PM

1. Well, if you use a digital intermediate like Cineform, then yes, it is three times bigger. However, I archive the native HDV and throw out the intermediate files. I can always convert them again and it is timecode perfect.

2. Still around $10, yes.

3. Since I capture everything to disk before editing, I just archive it and put away the tape. That gives me a tape and a backup.

Kevin Carter April 20th, 2007 08:17 PM

thanks Steve, don't understand a word on point 1.


All times are GMT -6. The time now is 06:20 AM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2020 The Digital Video Information Network