2 Replies Latest reply on Apr 29, 2013 7:35 AM by Dave LaRonde

    Colors are screwed up after export / import h264/avc

    Weax

      colortest-results-local.png

      Assume we have created some raw colors with AE. And exported the file with h264/avc codec (see the picture).
      I understand that exporting with chroma 4:2:0 can change the colors a little. It's ok. We play the file with local video player, RGB values are 1-2% away from original, it's not critical.

       

      But what I don't understand is - why re-encoding the file to h.264/avc with Adobe Media Encoder as standalone application leaves all the colors 100% correct, but if I will import the file to Premiere or AE, colors are visibly screwed up?
      Then export composition to h264/avc with the same settings as stand alone encoder and the colors are screwed up one more time by 1-2%!

       

      Am I doing something wrong? How to keep the colors when importing?

        • 1. Re: Colors are screwed up after export / import h264/avc
          Mylenium Most Valuable Participant

          Either the good old H.264 Gamma problem or simple quantization errors which you might probably avoid by working in 16bpc or 32bpc. Also keep in mind that AE can use color management and you may already see those differences when setting the comp viewer proofing to you monitor profile. Generally, though, such color issues are extremely difficult to track down. Things like your graphics hardware's acceleration features, VLCs selected decode method, color profiles and other color tweaks can influence this, both in mere perception of colors as well as actually skewing them. Start by working in higher bit-depths when re-importing files into AE and tippi-toe your way to the aforementioned color management stuff and so on...

           

          Mylenium

          • 2. Re: Colors are screwed up after export / import h264/avc
            Dave LaRonde Level 6

            ...and to add to Mylenium's comments, H.264 is a DELIVERY codec.  It isn't a lossless intermedate, aka production, codec.  H.264 is lossy, and bad things will happen with repeated recompression.

             

            The chances are good that you're not going straight to final delivery from AE: there's almost always another application that will utilize your AE work.  You should either render out of AE (using the Render Queue) in a lossless  codec if there's any kind of codec question -- I like QT's in the PNG codec.  It's also okay to render in the in thebest-acceptable codec for use in the next application.  If that happens to be H.264, someone could be sandbagging their delivery specs to save storage or it isn't much of an application.