4 Replies Latest reply: Oct 12, 2011 1:06 AM by keraunoscopia
keraunoscopia Level 1 Level 1

I created a disc image from a DVD using Disk Utility, and the Apple help guide suggested I select—in the drop-down menu of the image creation window—"compressed" before clicking "okay". As the disc image was being created, I found another tutorial, unrelated to Apple's site, that said to select CD/DVD Master.

 

My resulting image was saved as a .dmg file, and the tutorial's was a .cdr file, though a quick search on Apple Communities told me there's no need to worry about the difference between those two.

 

So my question is: was choosing "compressed" a bad idea? The DVD itself is just a home movie made using, probably, iMovie and iDVD, and I needed to make one copy.


MacBook Pro 17", Mac OS X (10.5.8), 2.4 GHz 2GB
Solved by BDAqua on Oct 11, 2011 11:24 AM Solved
On the DVD I wouldn't use compressed if possible, it'll save space but require many more resources to actually use it... it has to copy the data to RAM & Hard drive, uncompress it & such first.
Reply by Limnos on Oct 11, 2011 12:38 PM Helpful
And a I think video DVD is a compressed format already so it won't really save space. If you try compressing mp3 or jpg you'll also find they don't get smaller, and sometimes they get larger because of the compression overhead.

All replies

  • BDAqua Level 10 Level 10

    On the DVD I wouldn't use compressed if possible, it'll save space but require many more resources to actually use it... it has to copy the data to RAM & Hard drive, uncompress it & such first.

  • Limnos Level 9 Level 9

    And a I think video DVD is a compressed format already so it won't really save space. If you try compressing mp3 or jpg you'll also find they don't get smaller, and sometimes they get larger because of the compression overhead.

  • BDAqua Level 10 Level 10
    And a I think video DVD is a compressed format already so it won't really save space.

    Excellent point, thanks!

  • keraunoscopia Level 1 Level 1

    I wish I could give you both correct answers. That was awesome, thank you both! I'll refrain from compression in the future. The DVD came out perfectly. Were I to make a dozen copies, now I'll know that compressing isn't going to help.