ISO Compression?

[Dante of the Inferno]

Something that I've noticed when analyzing anime dvd's: some one-sided discs can hold up to 13-15 GB on the ISO.

Since the largest one-sided blank dvd's I've found only hold up to 4.7 GB, my question is:

Are high-capacity one-sided discs simply not available to outside of industry or is there some technique to compress the size of the ISO so it can fit on a regular dvd?

[Shadow Kira01]

I don't know but here may help you..

[GHDpro]

Are you sure you didn't put a Blu-Ray disc in the drive by mistake?

You can put roughly 4~5 GB of data on a single layer DVD and 8~9 GB of data on a dual layer DVD.

Of course with compression, you can fit much more data on such DVDs, but an ISO ripped from such a DVD will not be any larger than the disc it came from, unless you "unpack" and decompress the contents f the ISO.

And as (afaik) ISO or UDF doesn't contain any compression by itself, any compression would have to be in the content (ie: MPEG2 encoding in .VOB files for DVD video), not the container format itself.

[chikorita157]

If you want to fit the DVD video into a single layer disc, you must remaster it using some kind of DVD shrinking software which involves reencoding it so it will fit in a single layer disc. You can try DVDRemaster (Mac only) or DVD2one (Mac and Windows) which will only take the main feature and compress it so it will fit in one 4.7GB disc, but both options cost money and I don't know any other free alternative that would do the same.

I'm assuming that you own legal copies of the DVDs.

[Shadow Kira01]

Originally Posted by GHDpro

Are you sure you didn't put a Blu-Ray disc in the drive by mistake?

I am getting the same impression too as that the opening is suggesting that it is possible to burn 13-15GB of data onto an ordinary DVD+R or DVD-R. If you compress the ISO into an achieve file, burning it generally means you can view the content without unpacking it. If that's the case, it is possible to compress a 3-4GB ISO into a 200MB achieve. However, to compress 13-15GB of video onto a DVD+R and that disc will work fine in a typical standalone dvd player just don't sound possible to me..

[WanderingKnight]

Huh? A DVD can't hold anything more than 4.2 GB (approximately) worth of data, and dual-layered DVDs can hold double that amount. The ISO format doesn't compress anything, and even throwing the ISO at any compressing algorithm will probably get you a slightly larger file (there are some compression techniques that manage to shrink overall filesize by using the RAR algorithm to break down the ISOs in several small files, and it's pretty effective--I've seen reductions in size of about 50%!).

The 15 GB DVDs you're seeing are either Blu-Ray, which holds about 40 GB, or the now-deceased HD-DVD format, which as far as I recall holds between 15 and 20 GB.

[chikorita157]

Compression like a archive may save space, but you end up having to unpack the data before you can use it... I know that DMG image on Mac OS X compresses the data which is alot smaller than iso and is mountable in Mac OS X and Windows (using special software). Technically, like WanderingKnight said, the ISO format does not compress anything, it's merely stores the files in a CD image or ISO but can be compressed using third party software into a archive to make it smaller. Also, proprietary imaging software such as PowerISO can also achieve this without needing to compact the software, but burning the disc will require the amount of space when uncompressed.

With a video dvd, compressing is not practical, and you need to remaster the whole DVD in order to fit it to a 4.2 GB (actual size) disc.

[Dante of the Inferno]

Originally Posted by Shadow Minato

I am getting the same impression too as that the opening is suggesting that it is possible to burn 13-15GB of data onto an ordinary DVD+R or DVD-R. If you compress the ISO into an achieve file, burning it generally means you can view the content without unpacking it. If that's the case, it is possible to compress a 3-4GB ISO into a 200MB achieve. However, to compress 13-15GB of video onto a DVD+R and that disc will work fine in a typical standalone dvd player just don't sound possible to me..

Yes, it's a dvd, as it plays fine on everything, computer or otherwise. I checked around and saw that DVD Shrink can compress the iso's.

The dvd that I am currently working with has an extracted iso of 7.63 GB (8,003,968 KB).

So, if I want to cram this iso back onto a commercial disk, do I need to completely remaster the dvd, or try shrinking the iso in a way that it can still be read without having to unpack it?

[chikorita157]

Originally Posted by Dante of the Inferno

Yes, it's a dvd, as it plays fine on everything, computer or otherwise. I checked around and saw that DVD Shrink can compress the iso's.

The dvd that I am currently working with has an extracted iso of 7.63 GB (8,003,968 KB).

So, if I want to cram this iso back onto a commercial disk, do I need to completely remaster the dvd, or try shrinking the iso in a way that it can still be read without having to unpack it?

DVD Shrink only rips the disk contents onto the drive and remove languages and menus, does not actually compresses the ISO so it still may not fit onto a single layer DVD, so you would need to remaster the DVD using the software mentioned.

[Dante of the Inferno]

Originally Posted by chikorita157

DVD Shrink only rips the disk contents onto the drive and remove languages and menus, does not actually compresses the ISO so it still may not fit onto a single layer DVD, so you would need to remaster the DVD using the software mentioned.

DVD Shrink gives you the option to remove extra languages and subtitles, and also allows you to compress the vob/ifo/bup files in order to "scale down" to the size disc that you want (i.e. 4.7 GB).

That said, I did so and remastered the dvd and burned it. I watched the copy, and it looks "ok...." I'd like to see a little improvement on the quality, so I checked to see how much difference space-wise it would make to remove the extra languages/subtitles. It only comes out to about 400 MB. Does anyone know if that would be considered a "noticeable" difference (the scaling ratio changes from 52.4% to 58.3%)?

[WanderingKnight]

The dvd that I am currently working with has an extracted iso of 7.63 GB (8,003,968 KB).

So, if I want to cram this iso back onto a commercial disk, do I need to completely remaster the dvd, or try shrinking the iso in a way that it can still be read without having to unpack it?

Or use a dual layered DVD.

That said, I did so and remastered the dvd and burned it. I watched the copy, and it looks "ok...." I'd like to see a little improvement on the quality, so I checked to see how much difference space-wise it would make to remove the extra languages/subtitles. It only comes out to about 400 MB. Does anyone know if that would be considered a "noticeable" difference (the scaling ratio changes from 52.4% to 58.3%)?

What did you use to watch it?

You probably won't notice any difference if you used a plain old CRT TV. On a PC monitor or an HD TV, things are a bit different (though personally I don't think it'd be much of a change).

[Shadow Kira01]

Just a quick note..

Is there really that much of a quality difference between the XVID format and the ISO format? Perhaps, you might notice some differences with a HDTV but with standard televisions, I doubt you will notice much differences. However, the size differences of 700MB and 7000+MB seems to quite huge, I wonder why..

[jpwong]

DVDs use the MPEG2 format. Ever see how large one of those old .mpg videos are? XVID is MPEG-4. In general, new codecs > old codecs for space compression. Of course that means less things can play new codecs unless the hardware decoding standards are brought up.

[chikorita157]

I'm pretty sure that most older computers can play XVid videos fine providing that the resolution is standard definition (720x480) smaller file size and some DVD players support these videos... The problem is, that you need to spend time ripping the DVD and then encoding it which is time consuming... and not all DVD player support this...

Especially H264, although alot smaller it requires immense amount of CPU power which most, but all older computers will struggle with, especially HD resolution video.

[Shadow Kira01]

Originally Posted by chikorita157

I'm pretty sure that most older computers can play XVid videos fine providing that the resolution is standard definition (720x480) smaller file size and some DVD players support these videos... The problem is, that you need to spend time ripping the DVD and then encoding it which is time consuming... and not all DVD player support this...

Especially H264, although alot smaller it requires immense amount of CPU power which most, but all older computers will struggle with, especially HD resolution video.

True.. It does take a long time to convert a DVD into XVID rather than ISO which can be done in minutes. As for standalone dvd players.. Considering that many of which now have USB slots, it is only reasonable to assume that XVID works on most of them with the exception of the rather expensive dvd players.

[Jinto]

Originally Posted by WanderingKnight

Or use a dual layered DVD.



What did you use to watch it?

You probably won't notice any difference if you used a plain old CRT TV. On a PC monitor or an HD TV, things are a bit different (though personally I don't think it'd be much of a change).

The whole process of remastering itself makes the quality worse. You take something that is already lossy and apply algorithms on it that make it more lossy. Its not as bad as lossy*lossy more like lossy*log(lossy)... Anyway the differences should be visible in scenes with fast motion/high dynamics (where basically nothing of frame n can be reused in frame n+1) and in the overall contrast (very ugly when using beamers).

[Mooglar]

You can use poweriso to compress iso into DAA which is faster...

or use magic iso which has a feature to compress image files.

References:
http://club.cdfreaks.com/f59/iso-ima...ression-92002/
http://www.free-news-release.com/ISO...tail_9814.html

[WanderingKnight]

The whole process of remastering itself makes the quality worse. You take something that is already lossy and apply algorithms on it that make it more lossy. Its not as bad as lossy*lossy more like lossy*log(lossy)... Anyway the differences should be visible in scenes with fast motion/high dynamics (where basically nothing of frame n can be reused in frame n+1) and in the overall contrast (very ugly when using beamers).

I was going by the assumption that he wouldn't re-encode the output he got.