Why is ISO better than ZIP for storing DVD images?

[Bansaw]

I have a number of .iso images of my homemade DVD videos on my hard drive.
I am storing them.

Why not take a straight zip archive of the AUDIO_TS and VIDEO_TS folder and store that instead? If I need to make a disc , I simply use ImgBurn to burn the disc with the right file system.

Any comments?

[Baldrick]

You can burn it directly without extracting.
Many software and hardware players supports iso playback directly.

[Bansaw]

Thanks, ---- so, if by storing them as ZIP, the only thing I am losing is the convenience of having a mount-able, directly burnable ISO image?
Ie: the ISO is simply more convenient than a ZIP? (the ISO is larger in size becuase its less compressed right?)

[Cornucopia]

No, an ISO stores things in THE EXACT ORDER (with sector sizes and everything) that was on a disc. Zips/Rars/7zs do not. They just understand the filesystem.

For example, in a correctly formatted DVD, the IFOs and the BUPs should never be in neighboring sectors (to prevent inability to seek when damaged). ISOs would maintain their separation. Zips might not.

2nd example: 3DBDs use hard links for co-located media (the M2TS and SSIF files), thus keeping size to a minimum. Zips would not do this, so the size of the resulting disc meda would ~double compared to the original (and zip/rar compression would have little effect on this, since they're already lossy compressed).

Scott

[Bansaw]

Thanks Scott.
The 3DBD and the SSIF issue only applies to Bluray I believe, and my DVDs are SD so thats not an issue for me.

So, basically, the only advantage I can see from what you wrote is that if I burned a DVD disc from a Zip archive and it got damaged, then the seeking might be impaired more than if I'd burned it straight from an ISO.


...and I am wondering also, if I used a package like ImgBurn to burn the Zip file and make a DVD, would it not intelligently position the BUPs and IFOs to distant sectors?

[Cornucopia]

No, those are only 2 examples that I gave. There could be others. If you don't plan on keeping it as an ISO, I strongly suggest you extract the main movie, and zip that if you must. Then you won't encounter possible navigation issues that might incur with a change in the "location" of the sectors of some of those files.

But, seriously, why do you NEED the zip? What's WRONG with just storing as ISO? Couldn't you just put the ISO in a ZIP if you had to have a zip?

Scott

[hello_hello]

Keep in mind, most decent archive programs (WinRar, TugZip, ZipGenius etc), support extracting the contents of ISO files in exactly the same way they'll extract the contents of zip files, so if you create an ISO file you're not limited to only being able to burn it or mount it to get to it's contents.

It's been a long time since I've tried, but I'm pretty sure you won't reduce the file size much (if at all) by compressing the DVD folders to zip or ISO, so I've never seen much point in doing so. As video is compressed I doubt you'll compress it much further by zipping it. Likewise if you extract the ISO files you'll probably find their total size won't be much greater than the ISO. I don't think I've ever had playback/navigation problems due to burning the files in the VIDEO_TS folder rather than burning them from an ISO file. A decent burning program should be able to burn a compliant video DVD disc.

Mind you I store very little DVD video as I convert it before putting it on my hard drive, but I don't work with home videos. I've used MakeMKV to rip DVDs to an MKV file on the odd occasion, when I've wanted to keep the original video without converting it. I can't remember the last time I played video using a disc so for me there's no need for vob files etc.

[jman98]

Using ZIP is going to save you like 1% on the space. Try it. See what you get.

You've been told why not to use ZIP. If you're hell bound on doing it anyway, then do it. Stop looking for the rest of us to provide some kind of justification for a decision you've already made.

[Cornucopia]

It isn't unlikely that applying Zip/Rar compression to a lossy-compressed file (like MPEG, VOB, etc) will even make it GROW! The LZW-type of lossless compression is already part of the lossy compression algorithm, so the "redundancy" (which is where there is size savings) has already been removed from the file.

Scott

[hello_hello]

Using ZIP is going to save you like 1% on the space. Try it. See what you get.

You've been told why not to use ZIP. If you're hell bound on doing it anyway, then do it. Stop looking for the rest of us to provide some kind of justification for a decision you've already made.

The arguments against using zip (vs ISO) seem to be based on the ISO format's ability to store more information regarding how to burn the files to the disc, but I'm not sure how likely that'd be to apply here given the OP has referred to storing homemade DVD video. What sort of guarantee is there the DVDs he's backing up were burned "correctly" in the first place and that ISO should therefore be the format to use?

Even if you're ripping a pressed DVD and shrinking it to DVD5 size, what's the guarantee ripping to the ISO format is going to ensure the DVD5 copy is burned "correctly" after the video has been re-encoded? If you were ripping a DVD9 disc and saving it as an untouched DVD9 ISO, or a DVD5 disc as an untouched DVD5 ISO, then maybe......

There's a difference between asking questions relating to advice given in order to learn, and asking because you've already made up your mind to do it another way.

[jimdagys]

There's a difference between asking questions relating to advice given in order to learn, and asking because you've already made up your mind to do it another way.

Well said. Some people like to chew over alternatives as a way of learning.