Please help a Newb out with dvd recording

Discussion in 'Digital Video' started by imac005, Feb 14, 2010.

  1. imac005 macrumors newbie

    Joined:
    Sep 4, 2007
    #1
    I'm using Toast Ti 8 to burn movies. How come every time i burn a file (AVI, MP4...etc) to a dvd format the quality is worse on the disc. than just playing the file straight on my computer. The video I'm burning is always smaller than the size of the disc., so i don't understand why the quality is worse. Is there a setting in Toast that i have to change or something like that? Thanks
     
  2. spinnerlys Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #2
    That is because of two things.

    1. .avi, .mp4 and most modern video files use a codec that is derived from the MPEG-4 codec, Xvid/Divx or H264 for example.
    Video DVDs use the much older MPEG-2 codec, which is not as efficient and advanced as MPEG-4. Thus the video files using the MPEG-2 codec need more storage space (MBs, GBs) for the same length of video than a video file using the MPEG-4 codec.

    2. Most movies released on video DVD use a so-called Double Layer (DL) DVD, which can store up to 8.5GB (7.9GiB) of data, in this case video.
    Most writable DVD media that can be bought are Single Layer (SL) DVDs, storing only 4.7GB (4.37GiB) of data.

    As pointed out in 1., the MPEG-2 codec is not really space efficient, thus video DVDs are using DL-DVDs.
    The average length of today's movies is about 100-120 minutes. No problem for MPEG-4 encoded video, and no problem for MPEG-2 encoded video.

    But as you probably use SL-DVDs, the video on the resulting video DVD has only 45% of the original capacity to store its information on (as it would be with consumer DVDs), thus the bad image quality.



    Again in short:

    1. .avi/.mp4 files are more advanced and space efficient than video on a video DVD. Thus the .avi/.mp4 video files look better with less storage space occupied.

    2. Consumer video DVDs have 45% more capacity to store video on, therefore the video on a video DVD you burnt yourself (and used an SL-DVD for it) looks crappier than on the original DVD or even the .avi/.mp4 file.
     
  3. imac005 thread starter macrumors newbie

    Joined:
    Sep 4, 2007
    #3
    Thanks for the Info! So basically what i need to do is convert the Mp4 to mpeg-2 and then burn it on a DL-DVD, or is there another solution that well enable me to play the mp4 on a dvd player without sacrificing quality?
     
  4. spinnerlys Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #4
    90 minutes onto a SL-DVD should be fine, but that depends on Toast's settings.

    Look into the Custom encoding settings of Toast by clicking the MORE button on the bottom left while you have selected the Video DVD option.

    [​IMG]


    8Mbps = 1MB/s (8bit = 1Byte).

    A SL-DVD holds 4.37GB, so 4.37GB x 1024 (2^10) = 4475MB.
    So you have 4475s of quite good video if you use an average and maximum bitrate of 8Mbps.
    4475/60 = 74.5min.

    Also set the Motion Estimation to Best if it is an action film or any other piece with fast moving camera or objects.

    Maybe get a SL-DVD-RW to test some settings, maybe you can fit a 90 to 100 minute movie onto a SL-DVD.
     

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