Archiving from MiniDV back to MiniDV...

[Boyan Dob]

This might sound silly to some, but anyway here it goes...

I have tens of MiniDV tapes full of volleyball matches... Most of these recordings are NOT that important to me... (Recorded with Panasonic MX500, analog 3CCD camera.)

So, I am thinking which would be the best way to archive these tapes and to free many tapes for further recordings... I'd not like to lose too much of video quality, because sometime in future I might do some video editing on them...

Should I (re)endode them from mJPG (MiniDV) format to H.264 format with not too high compression setting (some other format perhaps)?
Which format/codec & settings would you recommend?

As for storing them, first I thought I'd put them on DVDs, but then I saw this software Firestreamer-RM (www.firestreamer.com), which means I could, for example, put 10 MiniDV tapes on PC, encode them with H.264/MPEG-4 codec (http://en.wikipedia.org/wiki/H.264) and then put all of that back on JUST ONE MiniDV tape, this way freeing/saving 9 MiniDV tapes. (BTW, one MiniDV can hold about 13GB of data, which is pretty good for highly encoded material.)

Your thoughts, ideas?

[Chris Barcellos]

Wow, all that to save $3.00 on a cassette of tape.

You will be losing quality by a reencode to the other formats you discuss. You will actually be going through two reencodes if you come back to edit something. I also figure that for every hour of tape you want to reencode, you can count on 4 hours a down time for your system. I 'm guessing reencoding, unless you are actually capturing some way in your chosen format. And how much time is tied up in the system in converting the files from there to a storable format to transfer it back to a tape.

Despite everyones clamour to get to a tapeless world, tape still seems like the most expedient storage medium....

[Boyan Dob]

Originally Posted by Chris Barcellos

Wow, all that to save $3.00 on a cassette of tape.

first, one tape in my country is $5, 20 cassettes so far. second, as said, i don't need these videos to be top quality. third, if i put em all from ten to one cassette i'll have all at one place when reviewing.

but on the other hand you are right. perhaps i should order some 100 cassettes from abroud (USA) for $3 or less (though i'll still have to pay customes 15% and tax 20%).

Originally Posted by Chris Barcellos

You will be losing quality by a reencode to the other formats you discuss. You will actually be going through two reencodes if you come back to edit something. I also figure that for every hour of tape you want to reencode, you can count on 4 hours a down time for your system. I 'm guessing reencoding, unless you are actually capturing some way in your chosen format. And how much time is tied up in the system in converting the files from there to a storable format to transfer it back to a tape.

i wouldn't reeconde everything, just those 'non-favorite tapes'. also, on a core2 duo reenconding is actually in real time or faster for XviD format... not sure for X.264, is it slower???

[Heiko Saele]

If that tapes were like 100 USD a piece I'd say you could load them on your PC and put them on DVDs in 20 minute pieces (in DV format, without losing quality). But the MiniDV tapes are really cheap so I'd like to tune in with everybody else and say don't bother!
You don't want to re-use tapes anyways because after more than like 5-6 times of re-use you cause more damage to your camera's video heads than you'd like to. I know what I'm talking about because at my workplace we use to re-use DVCAM and DV tapes until they show errors, and recently our very skilled free lance repair-technician told me we were really wasting a lot of money by re-using our tapes that often. He didn't have to tell me because he actually profits from it, but I guess he is just too honest because he can't stand the abuse of equipment... ;)

[Jack Robertson]

I have started to Archive my large projects to DVDs in native format, if there is a 1 hour capture for example which is approx 13GB, then that gets split across multiple discs automatically by the burning program in my case that is Roxio Easy Media Creator. To retrieve a file the program tells you on what discs to load and splices the file or files automatically back to their original state.

It takes a while to burn all that but I think it's well worth it.

On top of that I have two drives burning at the same time meaning I have 2 archive copies of everything, discs fail from time to time and seeing they are really cheap it's no problem.

Jack

[Ervin Farkas]

Jack, from what we know at this point, unfortunately disk life is much shorter than tape life - so all your work may be in vain...

[Jack Robertson]

Hi Ervin... I was always under the impression that tapes only last a max 10 years, whereas discs (CDs/DVDs) are supposedly rated at 100 years (now I would ofcourse not expect 100, but if I got 10 good years I would be happy, I would also most likely have tarnsfered to other future mediums by then).

Also as far as I know tapes have the following disadvantages;
1, Can become tangled by bad players/recorders (due to physical contact of head and tape) which ends up in destroying the tape
2, Magnetic fields (TVs, magnets etc)
3, Heat and maybe humidity?

CDs & DVDs can get scratched but not if you're careful... now unless I am wrong, I will continue to see discs as more superior for archival.

Jack

[Ervin Farkas]

Hi Jack and thank you for your comment. Personally I have no long term experience with CD/DVD media, but I can go back to tapes I filmed with a good old full size VHS Panasonic shoulder mount camera (aaah, anyone still remember those glorious days?) 20 years ago and see no quality loss. Yes, you can destroy anything and tape is fairly fragile, but if you don't put it in a low end machine and keep them in a cool dry place, you rewind them before you play them, you should be fine.

What I have stated about writable CD/DVD media is mainly from information I read. Key thing is, we don't mix up the two types of media - while pressed disks will last a lot more, those that we burn, will last a lot less. I can tell you this though: a friend of mine did some tests, exposed written disks to direct sunlight and the content was gone is as little as a few hours! Higher quality disks lasted a few days. Now, this is an extreme test, I admit, and we would not expose those disks to direct sunlight, but it brings up the durability of this media for sure!

I read about some disks called Golden Disks and I just spotted them in my local computer store here in Atlanta a few days ago. I hope I can find the time to look a little closer to them by finding some more information - they claim just what you stated in your post: they last 100 years. I'll get back as soon as I find some trustworthy info.

God bless,

[Matt Headley]

Yeah, you especially don't want to use mini-dv tapes over again. I've seen drop-outs in the tape show up after the second recording.

[Boyan Dob]

I've got new notebook with Vista Ultimate, and now I use Windows Movie Maker to import my video material from MiniDV tapes...

There are two options in Movie Maker, either to import in DV format/codec or Windows Media format/codec -- I wonder though, is it possible to somehow put Windows Media Codec to higher bitrate than default value of 4MBs?

Windows codec at default 4MBs is noticeably worse than MiniDV codec at its ~29MBs! BUT, if it would be possible to put WM codec at say 8MBs the quality would be about the same while saving a lot of disk space!

I have over 30 MiniDV tapes, and if I'd archive them all at DV format it would be about 500GB, and since much of my material is not that important I'd use WM codec for that...

Any ideas how to increase default bitrate for importing/recording in WM codec?

P.S. All my tapes were used/recorded only ONCE thus far, so, using them few more times is quite OK I think... (For important stuff of course I'll use new tapes!)

[Mike McCarthy]

Make sue you are not confusing MegaBITS and MegaBYTES. MiniDV is about 3.2MB/s or 25Mb/s. So a WMV file at 4MB/s would be larger than a DV file, but I would gues that we are talking 4Mb/s with is 1/6th the size of DV. Because it is a more efficient codec, you could conceivably get the same quality. If you are seeing a noticable difference, then the bitrate is too low, but if the option to change it is not available, then you might have to use DV encoded captures.

[Boyan Dob]

Originally Posted by Mike McCarthy

Make sue you are not confusing MegaBITS and MegaBYTES. MiniDV is about 3.2MB/s or 25Mb/s. So a WMV file at 4MB/s would be larger than a DV file, but I would gues that we are talking 4Mb/s with is 1/6th the size of DV. Because it is a more efficient codec, you could conceivably get the same quality. If you are seeing a noticable difference, then the bitrate is too low, but if the option to change it is not available, then you might have to use DV encoded captures.

Yes, I meant Mega Bytes (I've used in all cases MBs, I'd use Mbs for Megabits). But thanks for clarification anyway, it might help someone...

P.S. If I find any news about how to do it I'll post it here.

[Mike McCarthy]

Statement still stands, you are confusing MegaBITS and MegaBYTES. DV is ALWAYS 3.2Megabytes or 25Megabits, not the 29Megabytes that you stated, that is for uncompressed SD. WMV at 4MB/s should be fine for retaining all available info from an SD source, especially a DV one. Even at 4Mb/s it should be OK. FLVs in SD look good at 1Mb/s.

[Boyan Dob]

Originally Posted by Mike McCarthy

Statement still stands, you are confusing MegaBITS and MegaBYTES. DV is ALWAYS 3.2Megabytes or 25Megabits, not the 29Megabytes that you stated, that is for uncompressed HD. WMV at 4MB/s should be fine for retaining all available info from an SD source, especially a DV one. Even at 4Mb/s it should be OK. FLVs in SD look good at 1Mb/s.

Ahh yes, you are right! I've found out from where the confusion arose...

In WMV properties I see 4000 kbps (for video), while for AVI I see 28800 kbps (video only).

I suspected that it meant about 4 MBps (megabytes) for WMV, since that bitrate it what I'd expect WMV to have to record/backup videotapes! But it actually means just 500 kBps (kilobytes) or to say about 0,5 MBps (megabytes) which is in my opinion just TOO LOW for material at 720x576 25fps PAL video resolution!

So, I also suspected AVI at 28800kbps means about 29 MBps (mebabyes), but it in fact means as you say, 28800 kilobites per second, or 3600 kBps (kilobytes), or 3.5 MBps (megabytes).


Now, it's clear to me that default bitrate which Movie Maker uses is simply too low at 0.5MB/s (the information lost is clearly visible compared to AVI/DV file), so the question still stands:

How to increase the WMV bitrate for importing/recording in Windows Movie Maker?

(Well, I could import all videotapes in DV format and then re-encode to some other more efficient codec/format, but I don't see the need for this additional time-consuming step since WMV is a very good codec at hand, if only I had control over its bitrate when recording video!)

[Mike McCarthy]

For comparison, we export our display masters at 720p24 into WMV at 6Mb/s and they look fine when we play them on our 720p projector in our edit theater, so 4Mb/s should be more than enough to backup DV quality footage. WMV is a very efficient encoding scheme, and the numbers should not be compared with DV. Compared to HDV, which is 6 times the frames size at 25Mb/s, SD at 4Mb/s is a similar data rate per pixel. You will lose quality that you wouldn't lose in DV, but you should still get decent results for most intents and purposes.