Results 1 to 16 of 16

Thread: Compressing a .dmg

  1. #1
    Join Date
    Sep 2005
    Location
    Wah-key'-key
    Posts
    10,390

    Default Compressing a .dmg

    I need to burn a 4.9gb .dmg to a 4.7gb DVD. What is the best and EASIEST way for an untechie tutu to accomplish this?

    Mac powerbook G4
    10.4.11

    many mahaloz...

  2. #2
    Join Date
    Apr 2004
    Location
    Honolulu, Hawaii
    Posts
    10,147

    Default Re: Compressing a .dmg

    I am not that knowledgable in Mac OS and I profess that I am using Wikipedia's to tell me what a .dmg file is.

    Quote Originally Posted by from Wikipedia
    A file with the extension .dmg uses a proprietary disk image format commonly found on Mac OS X. The format allows secure password protection as well as file compression and hence serves both security and file distribution functions.
    So if you can't get that 4.9gb .dmg file to a lower value using what's available on the Mac then you have one of two options, depending on your situation.

    1) Assuming your .dmg file contains a collection of files, break up that collection into two sets, such that each set is less than 4.7 Gbytes.

    2) If your .dmg file only contains one file then your next recourse is getting a bigger capacity device like a 8Gbyte flash drive.

  3. #3
    Join Date
    Apr 2004
    Location
    Kapalama Heights.
    Posts
    5,198

    Default Re: Compressing a .dmg

    I think if you split up the contents of a DMG it won't unpack and install properly, but that's just a guess. Sue, you need a file compresser. Most DMGs you download on the web are ZIPped, I think. Your Mac comes with an archiver (not necessarily a compressor) which MIGHT work. Try doing a ctrl-click on the DMG file, choose "Compress (filename)" or "Archive (filename)" and see if that compacts your file a bit. .2 GB is a LOT of space, though, so don't get your hopes up.

    Try it and let me know if that helps. You should have a "(filename).zip" file in addition to the original "(filename).dmg" file. Compare their sizes to see if that worked! If it doesn't work, post again. Someone here will have better advice.
    But I'm disturbed! I'm depressed! I'm inadequate! I GOT IT ALL! (George Costanza)
    GrouchyTeacher.com

  4. #4
    Join Date
    Aug 2006
    Location
    Honolulu, Hawaii
    Posts
    505

    Default Re: Compressing a .dmg

    Most .dmg's are already compressed somewhat. you won't gain a whole lot, BUT you might be able to squeeze 250mb out of it to try to fit to 4.7

    On Mac all you have to do it right-click and select "Compress" (I think it was there in 10.4)

    You can also just burn it to a Dual Layer DVD-R (8.5gb)

    the DMG is an image that mounts as a disk. What exactly are you trying to copy?

  5. #5

    Default Re: Compressing a .dmg

    Here's a site with rundowns and links to different types of compression utilities for Macs, there might be something in there that will handle compressing your file down enough. I noticed quite a few have free trials to check em out.

    http://www.pure-mac.com/compen.html

  6. #6
    Join Date
    May 2004
    Location
    San Jose, CA
    Posts
    386

    Default Re: Compressing a .dmg

    This is getting complicated. I have a G4 iBook with OS 10.4.11 and thought I'd get sumpin out of this discussion.

    Sue, have you eliminated out-of-hand that flash drive suggestion by Helen?

    I now use flash drives frequently. Ferrinstance, when I take tons of pitchers of grandkids, I copy them onto a flash drive and give it to my daughter. I know they're much more expensive than DVDs, but they're also easily reusable.
    Born in Hawaii, too - Truss me

  7. #7
    Join Date
    Sep 2005
    Location
    Wah-key'-key
    Posts
    10,390

    Default Re: Compressing a .dmg

    Thanks, everyone. The .dmg I need to compress started out as a DVD of misc family video from over the years. I turned it into a .dmg, not noticing that it was 4.9gb, and returned the DVD to the owner. This was a couple of years ago and the owner has misplaced the DVD. The thought was to burn it to DVDs as gifts for other family members...DVDs that can be viewed via DVD players. Most, not all, family members have PCs, not Macs.

    My goal is to burn these DVDs with as little effort as possible. This entire subject is way over my untechie head!!!

    I'll check out your links, Peshkwe. Thx.

  8. #8
    Join Date
    Apr 2004
    Location
    Honolulu, Hawaii
    Posts
    10,147

    Default Re: Compressing a .dmg

    So I take it then you are dealing with one big video file instead of a collection of smaller but a lot of video files?

  9. #9
    Join Date
    Apr 2004
    Location
    Honolulu, HI, USA
    Posts
    7,326

    Red face Re: Compressing a .dmg

    Interesting. A .dmg is a disk image file, or basically the virtual representation of a "disk," which would include DVDs. I'm trying to figure out how a standard DVD leads to a .dmg that's bigger than the DVD, unless it includes a lot of overhead (and I thought .dmgs were already compressed).

    When you open the .dmg, what do you get? What's on the virtual disk contained in the .dmg? If it's just one big video file, that should be what you should be burning to a DVD. Unless you've already verified that the contents of the .dmg are indeed bigger than a standard DVD.

  10. #10
    Join Date
    Sep 2005
    Location
    Wah-key'-key
    Posts
    10,390

    Default Re: Compressing a .dmg

    Quote Originally Posted by pzarquon View Post
    [...]I'm trying to figure out how a standard DVD leads to a .dmg that's bigger than the DVD,[...].
    My thought exactly and why I didn't think to check the size of the .dmg before I returned the DVD.
    When you open the .dmg, what do you get?[...]
    There's a video_ts folder (with lotsa stuff!) and an audio_ts folder (with nothing in it!).
    Unless you've already verified that the contents of the .dmg are indeed bigger than a standard DVD.
    I don't have a way to do that now.

  11. #11
    Join Date
    Apr 2004
    Location
    Honolulu, Hawaii
    Posts
    10,147

    Default Re: Compressing a .dmg

    By any chance do you make an attempt to burn a DVD with what you have now?

  12. #12
    Join Date
    Sep 2005
    Location
    Wah-key'-key
    Posts
    10,390

    Default Re: Compressing a .dmg

    Quote Originally Posted by helen View Post
    By any chance do you make an attempt to burn a DVD with what you have now?
    Yes, I tried, but got a message that there wasn't enough space on the DVD.

  13. #13
    Join Date
    Apr 2004
    Location
    Honolulu, HI, USA
    Posts
    7,326

    Exclamation Re: Compressing a .dmg

    Quote Originally Posted by tutusue View Post
    There's a video_ts folder (with lotsa stuff!) and an audio_ts folder (with nothing in it!).
    Aha! These are standard parts of a DVD's filestructure, normally invisible. So, I think a free tool like ffmpegX should work. For "Source," point it at the folder containing the video_ts folder. For "Target," point it at a blank DVD. Hope it works.

  14. #14
    Join Date
    Sep 2005
    Location
    Wah-key'-key
    Posts
    10,390

    Default Re: Compressing a .dmg

    Quote Originally Posted by pzarquon View Post
    Aha! These are standard parts of a DVD's filestructure, normally invisible. So, I think a free tool like ffmpegX should work. For "Source," point it at the folder containing the video_ts folder. For "Target," point it at a blank DVD. Hope it works.
    Thanks, PZ. Once I get some time I'll give this a try.

  15. #15
    Join Date
    Aug 2006
    Location
    Honolulu, Hawaii
    Posts
    505

    Default Re: Compressing a .dmg

    If you have Toast for Mac (which every Mac user should own) there's an option to "Fit to DVD" and it will automatically compress the DVD image to fit on a 4.7gb DVD. It takes a while (1-2hrs) but it works

    Basically it re-encodes the video before it burns it to fit it onto a regular DVD

    ffmegX will work too
    Last edited by LocalMotion; December 20th, 2009 at 06:55 PM.

  16. #16
    Join Date
    May 2005
    Location
    Waimanalo
    Posts
    771

    Default Re: Compressing a .dmg

    Maybe just use a double layer 8.5Gb DVD blank?
    Greg

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •