6 Replies Latest reply on Dec 1, 2014 5:05 PM by WhitesideVFX

    Custom Pixel Aspect Ratio (After Effects CC 2014)

    WhitesideVFX Level 1

      Hi All,

      How do you create a custom Pixel Aspect Ratio for After Effects CC 2014. I need a PAR of 3.3, as it would help me solve a technical problem i've been having with projection mapping.


      I've tried editing the Interpretation Rules.txt file which was hidden within the Users\Appdata\Roaming\Adobe\After Effects\13.1 Folder. To remove the last # so i can at least see that I can set up a custom PAR.


      But it doesn't appear in the drop down menu when creating a comp, or interpreting footage.


      I've also made the same change to the Interpretation Rules.txt file in the Premiere PRO CC 2014\Plug-ins\en_US\ folder.


      And I've restarted my PC after changes just incase Media Core wasn't updating itself properly.


      I can see the Custom PAR as an export option out of Media Encoder. But thats not what i need. I need to be able to correct a render which had a PAR of 3.3 without losing pixel information, much like an Anamorphic workflow.


      Anyway, Any help would be appreciated.




        • 1. Re: Custom Pixel Aspect Ratio (After Effects CC 2014)
          Rick Gerard Adobe Community Professional & MVP

          I have never heard of that PAR in 20 + years of building all kinds of weird things in AE. If you are going to use non-square pixels you must have a device that will stretch the image back to undistorted. Are you sure that is what you want?


          If the answer is yes then you will have to work your project in square pixels and then create your non-square comp, nest the master and scale it to fit. 


          I think you have a basic misunderstanding of non-square pixels. Pixels don't have a shape. There is a grid that the blocks of information must fit into, But in reality there is no such thing as a non-square pixel. There is just distorted or undistorted images.

          • 2. Re: Custom Pixel Aspect Ratio (After Effects CC 2014)
            WhitesideVFX Level 1

            Hi Rick,


            You're right, it's no known PAR... completely arbitrary and custom to this particular job. I'll run you through my process.


            I have a projection surface (a basketball court) Which needs to have content designed onto it which is viewable from one perspective point (camera 1) in the stadium. The problem is that Camera 1's viewing angle to the court is quite shallow.


            This is what Camera 1 sees:


            I will be generating like this for the surface so that it looks like a deep 3d surface from "camera 1"

            3d content.jpg

            Now, the problem is that when I perspective correct the renders to fit what the projector will be projecting from straight down. There isn't enough pixel information for the height of the image. Meaning the pixels will smear.


            This is the image that would be projected from a top mounted projector to achieve the 3d effect from the image above, you can see the loss of information in the the height pixels.


            My solution for getting more information into the height is to render out of our 3d packages with a Pixel Aspect Ratio of 3.3. This was the sweet spot I found to get enough pixel information to match the pixel output of the projectors.


            The resulting render looks like this (note, the angle of the camera hasn't changed)


            As you can see, there is more height detail now, which will mean that that last row of pixels will be remain fairly sharp.


            So, at this point, I can render from my 3d applications, and conform to the projector dimensions, with very little information loss in the height of the projected image, and without compromising my 3d persepctive.


            I'm using the plugin "Camera Mapper" to project this render onto a plane which gets me the full frame of the projector at the right resolution, 4608 x 2304


            The tricky part how to composite elements into the scene in an intuitive way.


            If i want a horse to look like its jumping through the scene from "camera 1", like this:

            horse corrected.JPG


            Then in the that contains all the information, It will look like this:


            Now that's all well and good, but it'll be harder to create realistic looking effects from this view, because they'll all need to be stretched.

            I'd like to retain all the image information and just view the comp as though it's squished down.


            I imagine this could be done easily by changing the comp settings to a PAR of 3.3.


            That way, all the pixel information remains, but i can design in a realistically proportioned composition.


            I hope that gets you up to speed on my issue, and my request for a solution.


            So, in summary. I'll I'm really looking for is a way to customise the PAR options so that I have a custom available that I can apply to this, and only this scene.


            Does this makes sense?




            • 3. Re: Custom Pixel Aspect Ratio (After Effects CC 2014)
              Tim Kurkoski Adobe Employee

              Evan, I was able to create a custom rule in the Interpretation Rules.txt file in the After Effects preference folder, and it worked as I expected. Here's what I added to the file:

              # soft rule; create a fake rule that generates 3.3 PAR

              *, *, 99, *, * ~ 33/10/"myRule", *, *, *, *, *


              After making this change and launching After Effects, "myRule 3.3" is an available option in the PAR menu in Composition Settings, Interpret Footage, and the other expected places.


              (Note that this rule will nominally cause any 99fps file to be interpreted as 3.3 PAR. Since that's not a common scenario, probably not an issue, but if you feel uneasy about that you could just as easily define any of the other input parameters to be an effective no-op. You just don't want to leave all of the input parameters on * because all imported files would then be interpreted as 3.3 PAR.)


              You said you tried doing something similar on your machine, what exactly did you enter into the interpretation rules file?

              • 4. Re: Custom Pixel Aspect Ratio (After Effects CC 2014)
                WhitesideVFX Level 1

                Hi Tim,


                Thanks for your response.


                My test was to simply remove the # tag at the end of the text file to enable the custom option.


                Can you tell me where exactly the file should be located for cc 2014? Maybe I'm looking in the wrong place. You can check the paths where i found txt files in my first part.

                When I changed the txt in those it enabled custom Par for export in media encoder, but not footage/comps.


                I'll try adding your line when I'm next at the workstation.




                • 5. Re: Custom Pixel Aspect Ratio (After Effects CC 2014)
                  Tim Kurkoski Adobe Employee

                  My test was to simply remove the # tag at the end of the text file to enable the custom option.

                  D'oh! I forgot that we had that line there. That's a fine starting point.


                  The correct Interpretation Rules.txt file is located in the preferences folder for the version you are using. An easy way to get there is to open the Preferences dialog in After Effects and click the Reveal Preferences In Explorer button. For After Effects CC 2014.1 (13.1), this would take you to:

                  C:\Users\userName\AppData\Roaming\Adobe\After Effects\13.1


                  I suspect you may just be editing the wrong file. Also mind that the example rule there uses 10/11, which matches an existing PAR (D1/DV NTSC 0.91), and After Effects is smart enough here to not show duplicate entries for identical values. Once you change that to a custom value (33/10 for your case of 3.3) it should show up as you expect.

                  • 6. Re: Custom Pixel Aspect Ratio (After Effects CC 2014)
                    WhitesideVFX Level 1

                    Thank you Tim,

                    That did it. After Effects wasn't showing me the "custom" option because it was a duplicate.


                    All working now!