Lossless DVD re-authoring

[ggking7]

I have a lot of DVD backups on my hard drive and it's time to start re-authoring them to save disk space. I always use FLAC for my music files. Is there a lossless codec that works well for video?

[foxyshadis]

DVDs aren't uncompressed, like audio CDs. Lossless compression would be 5-10x the size of the raw dvd data. You'll have to look into lossy recompression if you want to do that. (DVD Shrink or DVD-RB to keep them in DVD format, or one of the many mpeg-4 compression suites.)

For nearly identical output in xvid as input, at around half the size typically (no one or two cd backups here), teegedeck has a good preset system in the xvid forum, now integrated into megui.

[bb]

ggking7,

to re-author a DVD losslessly you'll find DVD ReMake (Pro) useful:
http://www.dimadsoft.com

If you want to strip off everything except the main movie you should try DVDShrink - it's lossless as long as you keep the compression ratio at 100%.

The technique to save space is to drop content you don't need. There's no re-encoding involved. You may use DVDShrink to re-quantize the MPEG-2 video, too, which decreases size. But that is not a lossless operation. For higher compression ratios (final size below 70% of original), you'll find that a full MPEG-2 re-encoding does a better job, e.g. using DVD-RB.

bb

[CWR03]

If you're interested in a "movie only" backup, but you don't want to re-encode in a lengthy process, you might consider ripping in .IFO mode with DVD Decrypter with file splitting set to none. The result would be a .VOB file that will play as-is in nearly any video player. I believe there are tools that can strip away unwanted audio tracks which will save you some more space, especially if the .VOB contains DTS audio.

[ggking7]

I'm using DVD Decrypter now to rip a full ISO. It sounds like I should give "movie only" mode a try. A couple questions....

What is the difference between what (lossless) DVDShrink will produce and what DVD Decrypter in movie only mode will produce?

How much space do you save on average with either of those methods compared to a full ISO rip? I realize it can vary quite a bit.

[CWR03]

What is the difference between what (lossless) DVDShrink will produce and what DVD Decrypter in movie only mode will produce?
DVD Shrink would actually output a smaller file initially because you can uncheck the unwanted streams, whereas they'd be intact from DVD Decrypter. The problem would be that you'd still get either an ISO or multiple .VOB files from DVD Shrink. My suggestion was based mainly on ease of playback since you can open and play the .IFO rip just like any media file.
How much space do you save on average with either of those methods compared to a full ISO rip? I realize it can vary quite a bit.
Yes, it'll vary a lot depending on the length of the movie, the amount of extras on the disk and the different types of audio it contains (DTS is very large). Typically a .VOB file with just one 5-channel AC3 track will be about 2GB/hour. It seems like most of movies that are less than two hours still fill an 8.7 GB DVD, so in that case you're looking at a potential of cutting the required space in half.

This would take more time and processing, but you could work from your existing .ISO files by loading them into DVD Shrink, selecting a "movie only" backup stripping unwated streams, then outputting that to another .ISO and creating an .IFO from that. It's probably going to be a few steps to get to that point, but it should be fairly quick since there would be no processing of video or re-encoding, just transfer of data.