5 Replies Latest reply on Sep 28, 2016 5:53 AM by Rick Gerard

    MXF Interlaced Jagged Edges

    Pascal Greuter

      Hi everyone

       

      Our in-house format is 1080i, MXF OP1a, XDCAM 35, Interlaced (Upper) at 25 fps. Every time when I have some red colors in my footage, the lines are extremely jagged.

       

      Here is a cropped example:

      1080i50_MXF.jpg

       

      And here is the ProRes422 Version, also rendered interlaced with Upper field first:

      1080i50_ProRes422.jpg

       

      You can clearly see, that it just affects the red color, everything else is sharp and clean.

       

      I rendered the animation in After Effects as ProRes422 with Upper Frames (I also tried ProRes422HQ and 4444) and used AME to convert it into a MXF File. The ProRes is fine but after the conversion, everything red is very jagged. I think it has something to do with the interlace because when convert it as mxf progressive it is a lot better. But our playout server need interlaced files.

       

      Any help or advice is greatly appreciated.

       

      Regards, Pascal

        • 1. Re: MXF Interlaced Jagged Edges
          Rick Gerard Adobe Community Professional & MVP

          How are you judging the footage? If you are opening the interlaced footage in AE then the MXF files are probably not being interpreted with Separated Fields and the Pro REZ files are. Check file interpretation of the MXF files and make sure the fields are being separated in AE in the proper order. You can quickly see the interpretation in the info panel at the top of the Project Panel when the footage is selected. Jaggy edges on interlaced files are normal unless you tell the software to fix them by separating fields. The more movement in the frame the worse the jaggies.

          • 2. Re: MXF Interlaced Jagged Edges
            Pascal Greuter Level 1

            Hi Rick

            Thanks for your answer. I'm judging them on a Broadcast Monitor that is hooked up to my editing station via an AJA Video Card. In my example above, you can clearly see, that the jagged edges are only in the red color, not the other ones. I think it has something to do with the MXF Wrapper.

            • 3. Re: MXF Interlaced Jagged Edges
              Rick Gerard Adobe Community Professional & MVP

              Are you previewing an AE comp? Did you separate fields? A broadcast monitor is not going to separate fields and the only true judgement of quality, especially with interlaced files is when they are playing back at full frame rate, full resolution and 100% magnification ratio.

              • 4. Re: MXF Interlaced Jagged Edges
                Pascal Greuter Level 1

                I preview the file in Premiere at 100%, full res and full frame rate. I'm aware of most of the interlace issues because I work as a broadcast editor and motion designer for more than 10 years. But this is something new to me. It's not a normal interlace issues because it only affects the red color and not the other ones.

                • 5. Re: MXF Interlaced Jagged Edges
                  Rick Gerard Adobe Community Professional & MVP

                  There may be some new problems with the compression of the MXF files when you render interlaced. What do the files look like with you render them progressive? The only difference between a progressive file and an interlaced file when the footage is played back on an interlaced system is that the progressive file has two fields that are identical slices in time making up each frame and the interlaced file has two fields that are different slices in time making up each frame. There could also be a problem with the way your AJA card is displaying interlaced files. Are the screen captures from the computer monitor or your broadcast monitor?

                  Screen Shot 2016-09-28 at 5.30.42 AM.png

                  This definitely looks like interlacing from a freeze frame with separate fields turned off.

                  Screen Shot 2016-09-28 at 5.33.32 AM.png

                  There are fewer artifacts in the red when there is a yellow background. This magnified closeup of the Pro-Rez shows no interlacing artifacts:

                  Screen Shot 2016-09-28 at 5.38.52 AM.png

                  There are a couple of things that I would try. The easiest and first option would be to render an MXF file progressive, then re-render the same file as interlaced. See if that fixes the problem. The only thing that can possibly effect in playback is the way motion looks when the movement is at or near critical panning speeds. The second thing I would try is slightly changing  the color values. Your red is 224, 0, 10, your black is 0, 0, 0. The yellow is 254, 218, 0.

                   

                  Compressing any fully saturated color against a black background that is 0, 0, 0 is almost always going to cause problems. Introducing a bit of noise in the black background or raising the values slightly will help. Notice how much cleaner the red is against the yellow. if the yellow was brought down just a bit or even had 4 or 5 points of blue added you may get a clean render. If the red had a bit of blue in it that would also help. Bringing the black value up to 5, 5, 5 or 10, 10, 10 would also help. There would be some room for the compression to make calculations when it is dealing with the edges.

                   

                  I hope this helps. I've never seen an interlaced video system that couldn't playback progressive footage without problems but I'll acknowledge that there may be new compression problems with the MXF format that are giving you these nasty interlacing issues.