Quicktime Output Dimensions?

Discussion in 'Digital Video' started by Mac709, Feb 5, 2009.

  1. Mac709 macrumors newbie

    Joined:
    Mar 3, 2007
    #1
    I'm capturing HDV from a Sony HDR-HC7 using Easy setup HDV - 1080i60 Firewire Basic, FCP 6.0.5. The resulting file info shows

    Dimensions 1440 X 1080
    Codecs: HDV 1080i60, Integer
    (Little Endian), Timecode

    If I send a captured clip to Compressor via a droplet using the AppleTV preset I end up with a .m4v with Dimensions 960 X 540. But if I take the same clip, Export as a a Self Contained Quicktime Movie using "current setting", and send the resulting .mov to Compressor via same AppleTV droplet I get .m4v with Dimensions are 960 X 405.

    Why are the dimensions different?
    Am I losing video quality?

    Thanks
     
  2. CaptainChunk macrumors 68020

    CaptainChunk

    Joined:
    Apr 16, 2008
    Location:
    Tempe, AZ
    #2
    The reason why this is happening is because MiniDV based HDV cameras do 1.33x (i.e. PAR 1.33) horizontal compression to the recorded image from 1920 lines to 1440 lines. And this is because the camera's sensors are actually 4:3 natively. To adhere to DV specs, this is the compromise that has to be made, unfortunately. Therefore, FCP reads the footage as 1440x1080i because that's what it actually is to start with.

    The resulting output image (assuming that you output at full scale) will become an "un-stretched" 1920x1080. Your initial Compressor output to Apple TV is consistent with this: a 960x540 image after a 50% scale adjustment for proper delivery. But, I'm not quite sure what's happening after you re-export the resulting movie using the same settings. You really shouldn't have to do that anyway.
     

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