How much compression can I apply to a DVD .iso before quality loss becomes notieable?

Sorry for the double post! I screwed up the title to the first!

Hi all,
I am a relative n00b when it comes to backing up DVDs, but I have a huge Doctor Who collection which I need to put away to save space. So I bought a 2TB HDD, and I have been backing them up using the readom command in Linux, i.e. straight DVD9 to DVD9 .iso copies. However, with nearly 60 disks to go, I am rapidly running out of space on the HDD, so I figured it might be an idea to compress the .isos.
I’m not going to burn them to disk, so it’s not an issue, I just need access to the .isos.

So, my question is this: How much compression can i apply to the .iso before loss of quality becomes noticeable? I am using a 24" 1080p HD TV as a monitor, if that matters.

Even if I can shave a few hundred MB off the .isos, that would help some, but I want to preserve as much of the quality as possible.

Also, what would be the best software for the job? As I said, I have so far been using Linux’s readom command, and I have Handbrake and DVD95 installed. I also have access to a Windows 7 PC, so if there are better options for Windows, I am open to them.

Sorry for the long winded post, but any advice would be greatly appreciated! :slight_smile:

Being able to notice quality loss varies from video to video and is based upon the type of video (fast motion vs still shots, starting bit rate, etc).

Your best option may be to use a program like DVD Shrink and lower the quality of the menus and extras you dont watch and leave the main episodes untouched. However, the amount of space you save will depend on how much space the menus and other unimportant videos take up to begin with. You can do some tests to see what is acceptable to you.

Welcome to the forums!

It is possible to reduce just the extras using Shrink, but you won’t be reducing the size much.

Using the Windows computer, you should try another program called DVDRebuilder. You can re-encode the entire disk, menus and all, to fit a single layer dvd size. This is approximately 4.3gb. Most commercial dvds are much bigger than this, usually in the 6gb range or more, especially for tv series disks. You’ll want the full installer for the free version of DVDRebuilder.

I suggest trying this on one of your dvds and see if the results are acceptable. Use the HC encoder that comes with DVDRebuilder.

DVDRebuilder won’t decrypt your movies if they have CSS protection by the way. You’ll need to decrypt them with a commercial program, but there are free trials available. I’d get the free trial for AnyDVD for this, or the trial for DVDFab. DVDFab has the advantage of a free section within it called DVDFab HD Decrypter which will continue to work even after the trial is over. You should rip the entire disk to the hard drive first before trying to re-encode with DVDRebuilder, as it will be faster and cause less wear and tear on your optical drive. Rip in file format, not as ISO’s if you want to use Rebuilder.

If you have any issues, let us know, and we should be able to help.

Edit: The Pro version of DVDRebuilder (which I have used for years) can output as an ISO file. Don’t remember if the free version will or not. If not, it is simple to make an ISO from the dvd files though. A free program called ImgBurn can do this very quickly.

You can run DVDShrink and/or DVDRebuilder on linux using Wine. :slight_smile:

Thank you all for the replies. The encryption on ther disks doesn’t seem to be a problem,as DVD Decrypter zips right through them. I have heard good things about DVD Rebuilder, so I’ll give that a few trials and see how it goes.

What’s the deal with the CCE Encoder?? I come across a lot of posts from people who use it, but I was under the impression it cost a hell of a lot, and the free version leaves a watermark?? Is this true?

I’ll try the HC encoder for now though.

Thanks. :slight_smile:

CCE has a much less expensive version, called CCE Basic, which is what most of the amateurs use. It used to be $49. It has some restrictions on number of passes (two) and it hasn’t been updated in three or four years as far as I am aware. And of course, many people use pirated copies of the full version of CCE since it costs close to $2000.

CCE hardly matters, since HC has become so good. Development of HC continues and most of the amateur videographers believe it can hold its own or even surpass CCE these days in quality of output. CCE is still faster.

The free version of DVDRebuilder won’t do an .iso.
I’ve never had CCE but HCenc does a good job for me.
I’m using HCenc_025 but it came with HCenc_023 . It still may.
I changed to HCenc_025 in the rebuilder.ini file that is in the DVDRebuilder folder.
You also want to make sure this line is there " HC=HC.ini " if you want to use a HC.ini with settings you add.

I’ve used HC, the basic version of CCE and have tested the professional version of CCE extensively.

CCE is faster on single core machines but on modern multicore computers there’s not a great deal of difference speed wise.

As far as quality goes both are top end encoders and the differences between them are minimal.

Personally I prefer HC as I believe it’s closer to the original.

CCE tends to introduce slightly more grain than HC but the difference is subtle to the extent that I don’t see the point in anyone shelling out even for the basic version of CCE.


Thanks Wombler good to get some info from someone that has used both.
I can’t tell any difference between HCenc_023 & HCenc_025 as far as quality can you ?
I don’t know if the OP is interested but DVDRebuilder can be turned into a protable just by copying the folder from program files.
Paste it somewhere else C:\drive for example. Then uninstall & use the portable.

[QUOTE=cholla;2581020]Thanks Wombler good to get some info from someone that has used both.
I can’t tell any difference between HCenc_023 & HCenc_025 as far as quality can you ?[/QUOTE]

I haven’t actually felt the need to try version 0.25 yet as DVD Rebuilder Pro still ships with version 0.23.

Version 0.25 is basically a bug fix release of version 0.24.

Several rather technical tweaks were added (that I have to confess I don’t entirely understand) but according to JDobbs there isn’t any discernable difference primarily because of the way DVD Rebuilder uses HC.

If anyone else reading this thread is curious though and wants to try v0.25 then they’ll have to set it up it manually.

Just rename ‘HCenc_025.exe’ to ‘HCbatch.exe’ and place it in the ‘Encoders\HCEncoder’ folder in the ‘DVD-RB Pro’ installation folder.


Will an ISO still be an ISO if it is compressed at all? I would think it would then be a ZIP (or similar) and could no longer be burned directly to disc as a disc image (what an ISO actually is or at least used to be).

Granted, I’ve not used the programs being discussed here and don’t know what is possible these days.

Yes, you can make an ISO of the compressed video. I believe DVDRebuilder uses ImgBurn for this process.

It will not be an identical copy of the original movie, since compression has been applied, but the dvd-video can be put into an ISO. You can mount the ISO and view the contents, or burn it directly to a disk, just as you could an ISO of the original disk.

But the original question was can the ISO be compressed. Not can the video be compressed before turing into an ISO.

[I]‘How much compression can i apply to the .iso…’[/I]

I guess there are now tools that will open an ISO and compress the video that is inside of it. Maybe some day I’ll be in to this kind of thing and know what you all are talking about. :stuck_out_tongue:

Some programs can open an ISO and compress the contents…DVDShrink had this 7 years ago. DVDRebuilder cannot, to my knowledge, which is why I recommended ripping as files in my first reply in this thread.

I have ISO associated with Virtual Clone Drive on both my machines. A single click mounts it and it looks just like a DVD. That would probably suffice as input for dvd rebuilder.

[QUOTE=olyteddy;2581116]I have ISO associated with Virtual Clone Drive on both my machines. A single click mounts it and it looks just like a DVD. That would probably suffice as input for dvd rebuilder.[/QUOTE]

Yep, a mounted ISO should work fine as input for any other program. :iagree: