5 Replies Latest reply on Apr 25, 2012 6:37 PM by CH 4

    Media Encoder Flips a ghost Ultra Key frame

    CH 4

      First time using Ultra Key - Learning trial by fire.

      I've created a short video using a Canon HF G10 and ultra key to layer the video for effect I want.

      The Ultra Key is used for about 30 seconds of the 3 minute video and this anomoly only shows up during the ultra key treatment,

      The original footage is AVCHD footage and I've thrown a lot of video effect filters at the footage with the Ultra Key.

      The project rendered fine first go except I had to adjust the ultra key to prevent background from showing through one preformers black shirt.

      After doing this I notice some flickering. What I found is an outline ghost image from the utra key track is flipped upside down and randomly inserted into the final render, also a rectangular monotone transparent block is randomly inserted at times.

      Am I throwing too much at my computer or CS5?

      I have more than 30 keyframes spread over 4 effects on that track, is that too many or too taxing?

      I have rendered this clip a number of times and it seems when I re-open the project the Ultra Key footage isn't rendered so I render it again even though I am just making changes in the encoder. Let me know if you want to see those settings

      I am using H.264 at 1080P drop frame and 60 Frames (so far)

      This is for playback on a high def television from a computer.

       

      Here's my comuter specs

      Processor  2.2 GHz Intel Core i7

      Memory  8 GB 1333 MHz DDR3

      Graphics  AMD Radeon HD 6750M 1024 MB

      Serial Number  C02FC7GZDF91

      Software  Mac OS X Lion 10.7.3 (11D50)

       

      You can see a screen capture of one of the offending frames here, I varified that it is

      http://fredhunsberger.com/people/White%20Noise%20Mess.jpg

       

      Ultra key settings

      Ultra Key Settings

      Output - Composite

      Setting - Aggressive

      MATTE GENERATION

      Transparency - 40

      Highlight  -10

      Shadow - 55

      Tolerance - 90

      Pedestal - 50

       

      MATTE CLEANUP

      CHOKE - 10

      Soften - 10

      Contrast - 10

      Mid Point - 50.00

       

      Any idea why this is happening?

      Best, Fred

        • 1. Re: Media Encoder Flips a ghost Ultra Key frame
          Dave LaRonde Level 6

          I'm afraid you're taking it as an article of faith that Ultra Key works fine under all conditions.

           

          A lot of work goes into getting a successful chroma key shot, good chroma key lighting being the absolute most important one.  Adequate distance from the chroma key background to reduce spill is a close second.  Without a screen capture of the original green screen shot, it's tough to diagnose what you did.  But if you just put people in front of a green screen, shot and hoped for the best, I think you're running into green spill problems that won't be solved by a one-step keyer.

           

          You may have to take the shot into After Effects, cut the shot up into various pieces using animated masks to get the keys straight, or you may even have to do some rotoscoping.

          • 2. Re: Media Encoder Flips a ghost Ultra Key frame
            CH 4 Level 1

            Hi Dave, I wasn't taking it as an article of faith that the filter would work for me and am very pleased its worked as well as it did considering the contraints in time and space that I had shooting this.

            Whats interesting is how close I got to making this work first go and how adding a little tweak caused the encoder add these artifacts.

            I fugure more research is in order regardless, and hope to learn more about what would cause that issue.

            I have only looked at After Effects on other systems it did not come with the package my work bought for me.

            Thanks for you suggestions.

            Fred

            • 3. Re: Media Encoder Flips a ghost Ultra Key frame
              CH 4 Level 1

              I should have mentioned the 30 Keyframes are not applied to the Ultra key, they are scaling and lighting effects on the same clip, the matte looks good, in the preview pane and the artifacts do not show up in the preview either.

              • 4. Re: Media Encoder Flips a ghost Ultra Key frame
                Dave LaRonde Level 6

                If this was After Effects, I'd say, "turn off Open GL for rendering". 

                 

                What happens if you disable some of those many effects you applied to the chroma key shot and just render out the Ultra Key?

                Have you tried animating a garbage matte around the subjects?

                What does the original shot look like: is it lit properly for chroma key?

                • 5. Re: Media Encoder Flips a ghost Ultra Key frame
                  CH 4 Level 1

                  Wow this is warped. Copied the segment and systematically removed things, the problem persisted even with the Ultra Key taken out! Next to go was the lighting effect (nothing left) problem gone.

                  So Ive completed the project minus the lighting effect and am pretty happy, the Ultra Key looks great!

                  The pattern BTW is similar to the emboss filter and it IS a single frame of the clip with turned upside down, I've matched the patterns using layers in photoshop.

                  This was buggy, either its my graphics card or Premiere I figure