7.96GB limit on a DVD DL??

Discussion in 'Mac Apps and Mac App Store' started by iBeck, Oct 13, 2008.

  1. iBeck macrumors newbie

    Oct 13, 2008
    I'm trying to fit my 8GB project onto a DVD DL in Toast 9.02.

    The disc claims that it can hold 8,5GB of data, but Toast says 7.96GB is the limit.

    Why?? -and more important: am I doing something wrong?

  2. wrldwzrd89 macrumors G5


    Jun 6, 2003
    Solon, OH
    This is completely normal. The disc is lying, because optical disc makers (along with hard drive makers) count bits differently than your computer does.

    According to the manufacturers, 1 kilobyte is 1000 bytes. According to your computer, 1 kilobyte is 1024 bytes. The same applies to all the other units - megabytes, gigabytes, terabytes, petabytes, etc.

    To account for this discrepancy, simply take the advertised size (8.5 GB, in this case) and convert it to bytes by multiplying by the manufacturer's conversion factor (1,000,000,000 or 1 billion) then divide by 1,073,741,824 (your computer's bytes to gigabytes conversion factor). This yields about 7.92 GB usable (the real number is a little less than 7.92 but I've rounded it for convenience).
  3. kgarner macrumors 68000


    Jan 28, 2004
    I don't know for sure, but I believe it might depend on the type of data you are storing. I.e. if you are just storing files you can get 8.5 GB but if you are creating a DVD (movie-type project) the header data and such may require more room and limit the amount of space available.
  4. iBeck thread starter macrumors newbie

    Oct 13, 2008

    Ok thx alot

    it seems that i have to rearrange my hole dvd-project then... not what i was hoping to do.

    but then again dvd studio pro says that everything is ok! but i can't burn DVD DL on that computer...

    thanks anyway

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