9 Replies Latest reply on Nov 5, 2013 1:28 PM by Shane P

    Render Bug on Alpha Channel?

    Shane P Level 3



      I am attempting to render out a Logo with an alpha channel and I keep getting randomly "scrambled" lines in the final output. I have tried repeated times with various files. Sometimes there are quite a few scrambled lines, other times there are just a couple but enough to ruin a render and other times it renders cleanly. When I say other times it renders cleanly what I mean is that it I can render the same file with the same settings and it will render one version scrambled and the next version clean.


      I have tried this with various files and sometimes it generates these scrambled lines and sometimes it renders a clean file. All of the files were created in PS and it is not one file in particular. I cannot find any pattern.


      Here is a screencap of a file with a logo. The logo is not shown the black representing the Alpha channel. I rendered this out of AE using the folowing setting. QuickTIme>RGB+Alpha>Animation 100


      I am on Win 7 Pro 64

      AE CC 12.1


      Is anyone else having similar render issues?



        • 1. Re: Render Bug on Alpha Channel?
          Szalam Adobe Community Professional & MVP

          How long have you been experiencing this issue? Has it happened prior to the 12.1.0 update? Have you installed any codec packs?

          • 2. Re: Render Bug on Alpha Channel?
            Shane P Level 3

            Hi, thanks for the reply. I haven't had to do any rendering out of AE for a while but I noticed it with the 12.0 update installed. I was joping the 12.1 update would correct it.


            No I have not installed any codec packs. I was on Vista 64 using AE CS6 without any issues until early October. Then I did a clean install of Win 7 Pro and installed AE CC. I installed the necessary video driver for my card. GeForce 9400 Gt. Photoshop recognizes my Graphics ard so I wasn't suspicious of my video card/driver. 


            The only 3rd party apps I installed on my OS was QuickTIme, CCleaner and CuteFTP, all of which I ran of my Vista sytem without issue.


            Other than this "scrambling" issue everything else runs smooth.


            Any ideas? Is there more info you would like to know?


            Thank you,


            • 3. Re: Render Bug on Alpha Channel?
              Szalam Adobe Community Professional & MVP

              Some of this info might be useful.

              Have you tried running CS6 on your system since installing Windows 7?

              • 4. Re: Render Bug on Alpha Channel?
                Shane P Level 3

                I uninstalled AE and reinstalled and it is still doing the same thing. I have rendered some AVCHD footage with the PSD logo composited over the top and it rendered perfectly. This only seems to be happening when I try to render with an Alpha channel.


                MY SPECS


                Win 7 Pro SP1

                ASUSTeK Computer INC. P5QL PRO (LGA775)


                HP w2408 (1920x1200@59Hz)

                512MB GeForce 9400 GT (MSI)

                Driver: NVIDIA



                Realtek High Definition Audio


                8.00 GB Dual-Channel DDR2 @ 332MHz (5-5-5-15)


                Intel Core 2 Quad Q6700  @ 2.66GHz    44 °C

                Kentsfield 65nm Technology


                ATAPI iHAS120   6 ATA Device



                Name    HP w2408 on NVIDIA GeForce 9400 GT

                Current Resolution    1920x1200 pixels

                Work Resolution    1920x1200 pixels

                State    enabled, primary

                Monitor Width    1920

                Monitor Height    1200

                Monitor BPP    32 bits per pixel

                Monitor Frequency    59 Hz

                Device    \\.\DISPLAY1\Monitor0


                No Third party hardware


                Source Footage: PSD Files with several layers and an alpha channel.


                QuickTime 7.7.4


                No Third party effects or codecs.


                Other Software:

                PS CC

                AI CC

                PL CC

                PR CC

                AU CC

                DW CC

                FL CC

                BR CC


                Piriform's CCleaner


                GlobalScape's Cute FTP9

                Mozilla Firefox


                My system is pretty stripped down. It was a clean install of Win 7 Pro with the above listed software installed.

                • 5. Re: Render Bug on Alpha Channel?
                  Szalam Adobe Community Professional & MVP

                  I would like to see you try to render an alpha channel with CS6 on that same machine to see if it's an issue with CC specifically or with AE on that machine in general.

                  • 6. Re: Render Bug on Alpha Channel?
                    Shane P Level 3

                    Here is a clip of a quick export with a bogus logo. Just some text and a couple of graphic elements from AI. I rendered out as QuickTime>RGB+Alpha>Animation


                    I deleted Prefs, deleted all caches AE had generated from prior projects, purged, etc. It seemed to minimize but it's still doing it.


                    I thought I figoured out what was going on. One of the renders had several spots where the video looked scrambled. When I brought it into Premmiere and stepped through it I could see that part of the scramble was from another logo from a previous render. So that's why I delete all of my caches. It's not showing the scrables of the other logo anymore but as you can see it's still having an issue.


                    The logo is set on top of a single PSD layer in Premiere so it's not sitting against black so you can see it better.


                    Can't figure this one out for the life of me.


                    • 7. Re: Render Bug on Alpha Channel?
                      Shane P Level 3

                      I have installed AE CS6 and it is still doing the same thing. It has to be my system then. When I had Win Vista as my OS with AE CS6 it was flawless. It has to be something with WIn 7 or a driver or something. Do you have any ideas?

                      • 8. Re: Render Bug on Alpha Channel?
                        Szalam Adobe Community Professional & MVP

                        It might be something funky with your Quicktime install. Try rendering as a PNG sequence with alpha and then as a Quicktime with the PNG codec with alpha. See if either of those are different.

                        • 9. Re: Render Bug on Alpha Channel?
                          Shane P Level 3

                          I was getting suspicious of QT as well. I rendered several different Comps using QT>RGB+Alpha>PNG and all of them rendered beautifully. I then uninstalled QT and then reinstalled.


                          I rendered about 5 Comps in QT>RGB+Alpha>Animation and all rendered beautifully. I thought the issue was resolved. I then rendered another Comp and it had the intermitent scrambling. I don't know whether I want to smash a rock against my computer or my head.


                          All of the PNG's as I said rendered without issue.


                          A couple of the rendered files I brought into PPCC 7.1 I dropped into a time line and rendered the clips so they would play back real time. On a couple of the files during rendering the frame number would stop however the time indication render duration would continue.


                          After cancelling the render and trying to close PP, PP would lock up. I would have to go to the tak manager, end the PP process to colse it. On relaunch when PP would load it would stick at the "Loading Exporter QuickTimeHost.Prm" and would not launch.


                          I would then have to stop the "QT 32 Server" in the task manager.


                          Adfter that PP would launch fine.


                          Soooo...I know this is about AE but the fact that PP is having issues with QT I can't help but suspect that it's all related.


                          Any suggestions?