4 Replies Latest reply on May 27, 2014 1:06 PM by agtalpai

    Pixel aspect ratios


      Hi Creative Cow Crowd,


      I have been learning and using using AE quite exstensively in the past years (unfortunately, all by myself), but I never designed for television broadcast - until now.


      I've received a specification sheet with the following specs:

      Video format: MPEG 2 Program Stream

      Video frame size: 720x576

      Aspect ratio: 16:9

      Frame rate: 25fps

      Stream type: MPEG2 Long Gop program Stream

      Field order: Top field first

      Bit rate: 12Mb/s CBR

      Chroma subsampling 4:2:0

      Audio reference: -18dBfs

      Audio: Stereo Mpeg-Audio

      Audio bit rate: 224 kbps

      Audio sample size: 16 bit

      Sampling rate: 48khZ

      Peak audio signal level: -14dBfs


      I can make out most of these, however, my comp looks silly (tallish instead of wide) if I'm using PAL (i'm in Europe) widescreen settings. Did I screwed up something (I'm using PAL Widescreen settings with a pixel aspect ratio of 1,46) - is it ovverrideable at rendering or was this what they ment?


      I'm sorry if this is a basic question, I started learning on my own, so technical details are not my strongest points.

        • 1. Re: Pixel aspect ratios
          Szalam Adobe Community Professional & MVP

          You need to enable the pixel aspect ratio toggle for your comp window.

          • 2. Re: Pixel aspect ratios
            Rick Gerard Adobe Community Professional & MVP

            Your standard Pal comp (4:3) is rectangular pixels.

            It looks like they want a standard PAL Widescreen product, which is also rectangular pixels. Working inside AE in Rectangular pixels is not usually a good idea if you ever think you will need to show the product on the web or a mobile device. That's why your comp looks strange. There is a pixel aspect ration correction button that will fix the display problem, but I have a better idea.


            I would choose the Pal Widescreen Square Pixel composition for my project.


            Screen Shot 2014-05-27 at 11.00.35 AM.png


            Then render a digital intermediate and then use the Adobe Media Encoder to render your final output using the Mpeg and then use the PAL Widescreen preset and set up your encoder something like this. Make sure that you use Two Pass encoding for maximum quality. You should be able to find all the settings you need. Don't forget to check the audio section. (and don't forget to check your audio in Audition before you render your DI also. You can't really see if your audio meets the levels spec in AE very well.


            Screen Shot 2014-05-27 at 11.10.58 AM.png

            • 3. Re: Pixel aspect ratios
              agtalpai Level 1

              thank you mate, that sorted it out!

              • 4. Re: Pixel aspect ratios
                agtalpai Level 1

                Thank you for your in-depth answer, Rick - and sorry for not accepting your answer as correct: Szalam's answer answered the question, however your analysis proved to be very helpful while rendering the comp. In fact, your insisght is spot on: I used to make these comps in Flash because they were meant to be used for purpose-built Flash/swf-playing equipment. The simplicity of the previous tasks got me spoilt, I got a bit slack on reading up I guess...

                Thank you again!