How to save DV as compressed data

[kono]

Hello,
I'm interested in backing-up my mini-dv movies.
first let me mention that any other idea then what I'm asking here, will be welcomed.
my idea is to make the backups, with the minimal loss of movie quality, in a cheap way, (for further editing them in the future).
now, the most cheap media I found, and with enough storage - is DVD's, taking to account that 1 hour of DV is about 15-20GB.
I want to be able to put 15-20GB of dv onto a single or two DVD's. and in order to do so I need to compress it!! that's the problem. I don't care encoding the file to another video format or zipping it with winrar ect.. what I'm looking for is the best way to save it as a data, with the minimum space, and with the minimal quality loss. a sort of a lossless way for video storage, like FLAC does to WAVE files.
thank you very much,
avraham.

[neily]

Kono,

You are asking an impossible question. DV is already compressed, and for the data rate, for frame-editable video, is pretty much as good as you are going to get. There is no looseless further compression. My first advice would be to bite the bullet and back up the DV, as you will only regret it later if you don't, if backup is what you truely want. As time goes by, acceptable quality output increases - first VCD, then SVCD, then DVD, then HDTV - so any compressed backup becomes progressively less useful. If you just want a useable viewable version, convert it to a DVD.

You have to decide what you actually want the "backups" for. If you want ease of re-editing, go for an MJPEG codec, such as PicVideo. If you want compatability go for DVD-compliant MPEG2. If you want the best quality for the lowest bitrate, take a look at Doom9's codec comparison.

[communist]

DV is already compressed. You wont gain lower file sizes with a lossless codec - and even if - if you ever wanted it to put it back on DV tape you would have to reencode it back to DV (lossy) and loose some quality again.

For an editable backup just leave it as DV. Though compressing the audio with FLAC for ex. is what you could do, as the audio part in DV is uncompressed. But I'm not sure if the reduction of file size is worth the time needed to compress all the audio tracks for your tapes.
Also see this thread:
http://forum.doom9.org/showthread.php?s=&threadid=83030

[ronnylov]

1 hour of video on a single DVD can be done as DVD-Video at high MPEG-2 bitrate (8 Mbit/s video and uncompressed audio or 9 Mbit/s video with compressed audio). Then you can also use a standalone DVD player to watch it.

But you loose quality and it makes editing more difficult.

[HighInBC]

I have had the same goal as you, saving high quality unedited backup.

Just use 1 DVD for evey 20 minutes, I know it is alot of dvd's, but you do not want to recompress the DV files, you will never get that quality back.

Blank DVD's are cheap and you can hold 50 in a spindle, 50X20=1000 minutes... not too bulky. You may also want to make md5, sha1, or some other checksum files so you can check the integrety of the files later.

You can get a slight lossless compression with rar/zip on best quality mode, but this takes so long and the reduction so minor(only around 6% reduction) I don't bother.

[Longinus]

I always compress with RAR, or better yet, 7-zip, my DV video.
I know you said you don't care about zipping it, etc.. But in some cases is a very good option. Of course this is only for archiving and backup... If I want to edit it again, I have to wait (a long time) to decompress all the video streams.
So I make sure I don't need to..

I just compressed a little more than 10gb of DV videos with 7-zip, in the ultra compression. My compressed file is 6gb. Took 9 hours to compress it (P4 3ghz), but instead of 3 DVDs to store the original movies, I now only need two, and I still have some space left.. :D

[HighInBC]

Wow! 9 hours... I am impressed with 10gb to 6gb.

[Longinus]

Originally posted by HighInBC
Wow! 9 hours... I am impressed with 10gb to 6gb.

Me too.. I didn't think that was that much. But perhaps the kind of video helps. It's dark, and have lots of almost pure black. Try 7-zip one day. You need to config it to use the highest compression possible, otherwise you won't see that much difference from RAR.
But it takes A LONG TIME to compress... so I use it only to backup my finished projects, in DVD media, that is much cheaper than miniDV tapes.

[defaulk9]

to add my 2 cents...

If you value your time, consider keeping them on you miniDV tapes. Yes, they can be expensive, but you can find some good deals. This way you don't have to bother with all the fuss that goes into capturing every last bit of video, splitting files to fit on dvd's compressing them etc etc.

MiniDV is a fairly reliable medium as well. So long as you keep them magnet-free, they ought to last for some time to come.

Besides, if you have a decent video editor, you can keep your project independent of your DV. So if you finish editing, you can delete your source material off the hard drive, and keep the project. Any time you want to open up that project again, do a batch capture and only re-capture what you need. The editor will remember which tapes you have everything on and prompt you for them (just label your tapes). I think it's the best, if a little more expensive, way to keep track of your video.

[Longinus]

Originally posted by defaulk9
So if you finish editing, you can delete your source material off the hard drive, and keep the project. Any time you want to open up that project again, do a batch capture and only re-capture what you need.

I agree with Defaulk9. MiniDV tapes are not very expensive, and they can hold a lot of data.

Another thing you can do, that works with not-so-professional-but-still-good editors like Adobe Premiere, is to make it collect all the files to another folder, cutting only the used parts of the videos and removing everything not in use.

[Malcolm]

For those of you who still want to backup compressed DV material on DVD, there are some compression tools that are better with 'mutimedia content' than 7zip or rar. See the following link for a very good comparison: http://www.maximumcompression.com/. Especially the 'summary' link.
There is UHARC (and WinUharc) which is free + very very good! And also WinRK, which is commercial but - as it seems - the best compression tool around. But beware! The compression times are much(!!!) longer than with 7zip, rar, zip. Sometimes factor 10 and above!

Btw. some of you might know jpegtrans. With this tool, you can losslessly(!) optimize + convert jpeg files to use progressive and/or arithmetic coding for the huffman compression.
Since DV is very akin to JPEG, wouldn't it be possible to write a tool that does the same as jpegtrans? Before playing such a DV file it sure has to be reconverted.

Btw. there is also Stuffit, which i guess does the same as jpegtrans. It usually achieves 30% compression on jpeg files!

Greetings,
Malcolm

[communist]

While you're free to do whatever you like with your DV files IMHO the easiest and troubl-free solution is to keep it on (mini)DV tapes. You never know how easily heavily compressed files can get corrupted and if compressing and decompressing can take up to 10+ hours I rather transfer 10hours worth of content to tapes in that time :)

Oh and time = money so.. ;)

[aebbeka]

Sorry to bring back a really old thread, but I was amazed to read about the compression utilities out there that are so much better than rar. I've been using rar to archive all my DV files, even all the raw footage (if it's worth it), onto DVD. I get about 10-15% compression, nowhere near your amazing 40%.

Is 7-zip compatable with any zip utility? My concern would be using some proprietory compression utility, that in 10 years I might not be able use anymore. I like rar because i know it will be around, or atleast compatable with something, for a long time.