6 Replies Latest reply on Oct 25, 2011 10:40 PM by DavidMSmith

    ChromaKeys XH A1 & AE

    DavidMSmith

           I am currently looking into finally buying a decent camera. Im leaning hard towards Canon XH-A1. I have read :

       

      1) AE has issues with MPEG files. But I have never had any problems with mp4 in AE CS5.

       

      2) That hdv is not the best for chromakeys.

       

      When I pull keys in AE, I use Keylight. Considering that I have pulled some pretty impressive keys from mp4, should I really be concerned with the cautioning towards using HDV footge to pull keys? Yes I do a lot of keying. In fact most of the keys I have pulled fly in the face of everything I have read about keying, I shoot in an unevenly lit tight space with the cam about four feet from the screen. Here's a sample of one the first keys I pulled from an mp4 using keylight

       

       

      Yes there are some artifacts and the key could be tighter, but this is one of my first keys, they have gotten better. I know that regardless of how good the software, it really comes down to having solid source footage, you can add shine to poop, but it will still be poop.

       

      So my question is, Should I be that concerned with the cautions against using XH A1 for chroma keys? And what are the major issues I might have?

        • 1. Re: ChromaKeys XH A1 & AE
          Todd_Kopriva Level 8

          > AE has issues with MPEG files. But I have never had any problems with mp4 in AE CS5.

          That's old information. CS5 and later deal with MPEG-based codecs fine.

           

           

          > That hdv is not the best for chromakeys.

           

          That is an understatement. It would be better to say that HDV is abosolutely terrible for color keying.

           

          The gist of the issue is this: HDV is very heavily compressed, and the compression used throws away exactly the information that you most need for color keying. It's information that humans don't notice as much (which is why the compression scheme was created this way), but it's information that is vital to the color keying software.

           

          You want to use the least compressed, highest-quality footage that you can get your hands on for color keying.

           

          See this:

          "Shooting and acquiring footage for keying"

          1 person found this helpful
          • 2. Re: ChromaKeys XH A1 & AE
            Todd_Kopriva Level 8

            BTW, why are you referring to .mp4 and HDV in the same post? These are not the same thing.

            • 3. Re: ChromaKeys XH A1 & AE
              DavidMSmith Level 1

              Yes, I am aware they are different. I just had those two separate concerns. I mentioned mp4 because of the MPEG issue, the XH A1 outputs a MP2.

               

              Do you have any suggestions for a good prosumer camera? I was also interested in an XL2. But I want the cam that will work best.

              • 4. Re: ChromaKeys XH A1 & AE
                DavidMSmith Level 1

                I have also read that I could use a device like Intensity to bypass the cameras compression codec, it seems like a viable option. I do appreciate the feedback. I think I am just going to go with the XH A1 and if worst comes to worst, also buy an Intensity shuttle to get 4:2:2 instead of the 4:2:0 progressive from XH A1's internal compression. that combined with Keylight should do the job.

                • 5. Re: ChromaKeys XH A1 & AE
                  Todd_Kopriva Level 8

                  Yes, it is a good idea to get the 4:2:2 (or 4:4:4, or whatever) color information straight from the camera, bypassing extraneous compression. That makes a huge difference.

                  1 person found this helpful
                  • 6. Re: ChromaKeys XH A1 & AE
                    DavidMSmith Level 1

                    Thank you very much, Todd. Have a good one.