2009 August 11th, 17:08
Making ISO images of HDV tapes?
I'm working on my first feature film and we have a $0 budget. We're about 1/2 through filming and already used 22 tapes. We just don't have the money to make copies of every tape.
I have a few hard drives laying around I could keep backups of our tapes on indefinitely. Is there a simple way to make an exact bit for bit duplicate of a tape similar to a CD/DVD ISO file?
The reason I ask is because different apps seem to capture slightly differently and storing a single large MPEG file for the tape doesn't feel ideal. I use linux and dvgrab videos seem to be disliked by Final Cut Pro. When I capture with Final Cut Pro then Cinelerra and Adobe Premiere don't work as well with the files. I assume they all use slightly different container file but the MPEG stream is probably identical.
However, if I'm able to create an ISO of the tape then I never have to worry about such issues. I can just write it back to tape and capture with any application I choose.
2009 August 11th, 17:25
you answered your own question. if you want to make an ISO, then do just that. Not sure why you would want an ISO though, wouldn't you just store the original footage on a large drive ?
What's the advantage of an ISO ? ... it can become corrupt on a hard drive just like the original file would, so what's the point ? , and it's also an extra step.
Pop the footage on a hard drive, and put it away for safe storage.
I think perhaps you are not understanding the process of tape. When you backup your video footage that is on a TAPE, you have in fact, made a bit for bit duplicate on your hard drive. How else would you edit your footage if you don't first get it onto your hard drive ?
Originally Posted by wescotte
2009 August 11th, 17:47
using FCP, I would capture the hdv footage to a .mov using the simple setup or whatever...after that, you can fit most of the stuff on a 500gb - 1tb drive. When you start using the footage for editing, if you have problems with programs reading the files, use fcp/compressor to change them to a type the program will work with. Did I miss something, or what's the problem?
2009 August 11th, 19:07
Hard drives don't store footage indefinitely. They die, and it is not a question of if but of when!
If you want an exact copy of your tape you'll have to do a camera to camera dub. Whenever you run a tape through an editor you get changes in the data.
Cinelerra is out - Open Movie is in!
I thought Cinelerra was a dead fork ...
Can't say anything about Premiere, but I never had a problem with transferring QT files between FCP and Open Movie.... well, sometimes, rolling back the QT version on the Mac helped, though.
Are your libraries on the LINUX box up to date?
2009 August 14th, 05:36
How do you make a bit for bit image file of a tape than can be written to a new tape? When you capture you're storing your mpeg2 stream in whatever container your capture program wants. These containers are sometimes problematic between various NLEs.. If I create an ISO image file it doesn't matter what NLE I capture from because it's exactly the same as the original.
Originally Posted by Jack Frost
Sometimes (I believe it's the case with FCP) it doesn't even use the original stream but reencodes them into a intermediate codec. FCP uses ProRes which is ONLY compatible with Mac.
I haven't exactly verified it yet but I'm pretty damn certain that if you capture your tape to a single file and write it back to another tape you loose all the information pertaining to scene detection.
Originally Posted by Jack Frost
The reason I want to use an ISO... RAW bits rather than a captured file is it's an EXACT duplicate.. You're not going to get an exact duplicate (to store on a hard drive) any other way.
Yes, I plan to keep the tapes for the original backup but I have hard drives laying around that I plan to use as a secondary backup. If I have a bit for bit exact copy ISO/image of a tape it makes it easier restore a project in the event of a problem.
I guess what I'm trying to verify is even though these containers are different are we getting an exact copy of the mpeg2 video/audio streams in the capture/restore to tape? Will I loose the ability to scene detect if I write to tape the single mpeg file?
2009 August 14th, 05:44
When I capture stuff using dvgrab/kino FCP doesn't like the files. When I capture with FCP they seem to function just fine on cinelerra/kino/ffmpeg/mplayer wathever..
Originally Posted by cgbier
This leads me to believe the capture process is dependent on what software you use as they all seem to do things slightly differently. That's the reason I want to create bit for bit ISO type images of my tapes so I can avoid these little problems. My original tapes are my primary backup but I'd very much like to use these hard drives I have laying around as a secondary backup.
The project I'm working on is just too large to risk having only a single backup. We're about 50% done with the project and hit 22 HDV tapes. We just can't aford to make duplicates of everything. I have over a TB of space on various HDs where I can keep a secondary backup but I'm trying to figure out the best way to do it.
Capturing each tape in a single .mpeg file via whatever application just feels like the wrong way to do it as my experience says each capturing program does things slightly differently. I may loose the ability to perform an accurate scene detection on a duplicated tape. Or if somebody else tries to restore the data with another application other than the one I originally captured from might also run into problems..
If I can develop a method to store a bit for bit copy of the tape in an ISO/image type manor I don't have to worry about these issues.
Maybe I'm just being paranoid but I'm very inexperienced with DV/HDV and never had a project more than a couple tapes long.
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