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ADVC 700 color space

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  • ADVC 700 color space


    Background of the project:
    I am working on a project to create green screen shots of an actor that I will use in Flash. I'm using Combustion to create the alpha channel + video that I then bring into the Flash Video encoder and create the alpha channel encoded video .flv files. The green screen footage was shot with Betacam and I imported the footage from betacam through the ADVC - 700 into EDIUS. All was well, until I tried to make the keys in Combustion.

    I could not create a clean key with the imported footage (blocky around the edges). I know the EDIUS product works in 4:2:2 color space, but am I wrong in guessing that the ADVC - 700 is creating 4:1:1 color space video when I digitize it? As a test, we had access to a Pinnacle Targa 3000 card and digitized the footage with that using it's native YUV 4:2:2 capture setting. This footage keyed very nicely in Combustion. So I am worried that, while using the ADVC - 700 for video capture is fine for everything else, it is not a good option for capturing green screen footage? I can't seem to accept this because I know the ADVC - 700 does a great job but I've seen the results first hand between the two capture devices. Any ideas what I may be doing wrong? I've read everything I can find on this forum and can't seem to get a really straight answer. Thanks in advance....

  • #2
    The ADVC700, like all the DV ADVC products, capture to DV space. This means 4:1:1 for NTSC DV and 4:2:0 for PAL DV.

    EDIUS will upsample the original footage and work in 4:2:2 (or better) space, but in general for keying you want as much chroma data as possible, so if you have an analog capture board that can do 4:2:2 or better, I'd use that.

    Alternatively, you could try creating the key in EDIUS. If you leave the Show Key option enabled in the Chroma Keyer, you can export a grayscale matte which you should be able to use as a key matte in Combustion to create your FLV with alpha.


    • #3
      color space

      Thanks for the info. at least I know now how it is capturing. I'll give the matte a try to see how it works. What Canopus/GV product would you suggest for capturing 4:2:2 video? Thanks again.

      Last edited by daveAt; 08-21-2008, 09:40 PM.


      • #4
        If it's SP Betacam - EDIUS SP (that's where it gets its name from, actually)