7 Replies Latest reply on Feb 27, 2008 8:16 AM by (John_Rich)

    Problem with rendering RGB with alpha

    Level 1
      I have AE 6.5. I suddenly began having .AVI's with alpha channel rendering with a flickering background with numerous flashing colors.
      I did system restore, reinstalled 6.5 with no help.
      No new programs, not hooked to internet, using 2 gigs RAM with AMD athalon FX 53,Nvidia GeForce FX 5500.

      I tried several different projects which have previously worked and they do the same thing.
      Rendering as Video for Windows with no compression. RGB + Alpha
      Rendering with just RGB doesn't have the flickering, etc.
      Preview set to "off" in comp window.
      Any help would be greatly appreciated.
      Thanks in advance.
      John Rich
        • 1. Re: Problem with rendering RGB with alpha
          David Wigforss-Hv1BNN Level 2
          As a workaround, can you render to QT:Animation? Same problems? Also, do you still have the flickering problem if you import that QT:Anim and rerender it as an AVI?
          • 2. Re: Problem with rendering RGB with alpha
            Level 1
            David,
            Thanks for answering.
            I guess I was hoping for some way to get back to where I was rendering out the relatively simple comp (text and fractal noise and glow) as an AVI. I was rendering using both the "advanced" and "standard" rendering plug-ins with no help (ie open GL was apparently not the problem).
            Also, my version of Quicktime is 6.x so I doubt that is the problem.
            I'm thinking it is a hardware problem now.
            Do you have any thoughts what could just affect the alpha channel only.
            Thanks in advance.
            John
            • 3. Re: Problem with rendering RGB with alpha
              Jonas Hummelstrand Level 2
              One of the tips here:
              i http://generalspecialist.com/2007/02/troubleshooting-after-effects-7.asp
              ...is to remove third-party codec packs.

              Like David said, render to QuickTime Animation @100% which is lossless but compressed so you get a lot smaller files than uncompressed AVIs.

              - Jonas Hummelstrand
              http://generalspecialist.com/
              • 4. Re: Problem with rendering RGB with alpha
                Level 1
                Thanks for the great web-site.
                I was able to render the comp with Quicktime fine. I forgot David's second suggestion to rerender as AVI so I'll do that.

                I can't figure out how to uninstall the codecs. I would appreciate any help along those lines.

                Thanks for the great advice.
                John
                • 5. Re: Problem with rendering RGB with alpha
                  Level 1
                  This is really crazy. For some reason, I was just testing the clips I made with AE Video for Windows - Uncompressed, in Windows Media Player 10 and I kept getting these flashing playbacks.

                  For some reason I wasn't testing the clips in Premiere. Today I did and they work perfectly in Premiere, even though they still flash in Win Med Player. I suppose I could uninstall Media player and redownload it.
                  That saved me some major reformatting, etc.
                  Thanks for your advice.
                  John
                  • 6. Re: Problem with rendering RGB with alpha
                    bogiesan-gyyClL Level 3
                    > I have AE 6.5. I suddenly began having .AVI's with alpha channel rendering with a flickering background with numerous flashing colors.

                    But when you composite these lcips I'll bet the alpha content is not really there.

                    We used to have this problem with the Media 100 hardware codec when rendering form After Effects. The alpha channel was full of the creepiest stuff, frame buffers motion blur and effects from other compsand it was really there. Playing the clip back in Media 100 or in QT showed the alpha channel's bizarre content.

                    However, if you turned off RGB and viewed alpha only, the stuff was gone, absolutely transparent. If you dropped the clip into a timeline, the alpha behaved normally.

                    We never did figure it out, just lived with it.

                    bogiesan
                    • 7. Re: Problem with rendering RGB with alpha
                      Level 1
                      David,
                      Do you think this "flashing" is Media Player's problem, or After Effects generating "funny stuff".

                      I was thinking about Uninstalling Media player and re-installing another download.

                      The Quick time player shows no junk. If I want to revue my clip in a player, I may just have to go to QT since Premiere doesn't have any problems with the QT clips.

                      Thanks for the help.
                      John