Why does a 2GB video file not fit on an iDVD project?

Discussion in 'Mac Apps and Mac App Store' started by TitanTiger, Sep 26, 2010.

  1. TitanTiger macrumors 6502

    Jun 8, 2009
    I have a 2GB m4v file that I wanted to use iDVD to create a movie for. But even taking it off of Best Performance and instead using High Quality, the movie is too large to be burned. It's showing it as a 4.81 GB project.

    I'll admit my ignorance here...what gives? How does a 2GB file grow that large when being encoded as a DVD?
  2. spinnerlys Guest


    Sep 7, 2008
    forlod bygningen
    The 2GB .m4v file uses the H264 codec, an MPEG-4 variant.
    Video DVDs use the MPEG-2 codec to encode the video.

    MPEG-2 is older and less space efficient than MPEG-4, thus the transcoding process from MPEG-4 to MPEG-2 creates a larger file.

    An SL-DVD can store up to 90 minutes with medium quality, an MPEG-4 video of the same size (4.37MB) can store much more than 90 minutes.
  3. PinkyMacGodess macrumors 601


    Mar 7, 2007
    Midwest America.
    I figured it was a compression issue. I had no idea that the efficiency of the two was so dramatically different.

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