5 Replies Latest reply on Feb 28, 2010 10:52 PM by mongo106

    Can someone pls help?  Not ustanding import/export aspect

    mongo106

      Hello all,

         

      First off please excuse my lack of information.  I recently got into digital camcording, and have a simple Sony DCR-DVD610 which outputs in MPEG-2 to the memory card an am shooting in the 4:3 AR.  I have Adobe After Effects CS4 and Sony Vegas 9.

       

           Let me give a scenario I'm sure you have heard many times and you can point me in the right direction because I am a wee bit lost.

       

           When I view the raw .mpg on my computer it is of course interlaced, and everything seems in proper aspect ratio.  When I view a recorded plate.. it is round.

       

           Now I create a new comp in AE, which is defaulted to 720x480.  I import this vid of the plate.  My plate vid now seems stretched, I can already see this, the plate is no longer round.  I go ahead and do what I want with new layers and when it comes time to add to the render queue and render.. I choose the default, "Video for Windows" (.avi) lossless and render. 

       

           The resulting vid is the same as I saw in After Effects, out of aspect and the plate is now fatter wide than tall and no longer round.

           If I either stretch to 720x534 or to 640x480 the resulting output .avi is in correct aspect but I see loss.

       

           What am I doing wrong?  This is a standard SD cam with both 16:9 and 4:3 and I dont understand why After Effects always destroys the aspect.   Can someone please help this noob understand? 

       

           I'm not sure what the best way to output my videos to send to friends on the net etc.

       

           Please help!   Thanks so much,

       

                 Michael

        • 2. Re: Can someone pls help?  Not ustanding import/export aspect
          Mylenium Most Valuable Participant

          What am I doing wrong?

           

          Pretty much everything... In simple words: You are not consciously concerning yourself with retaining pixel aspect ratios (PAR) at all anywhere in your production chain, that's why it ends up in mayhem. The behaviors are all perfectly normal

           

          • When you import footage, make sure it is correctly interpreted. NTSC 4:3 is 480x720 at a 0.9 PAR. Verify using file --> Interpret Footage --> Main
          • Use the same to verify your field settings. If the target is computer output, fields should be off
          • When adding to the comp, use matching settings

           

          Computers always use square pixels, so using native NTSC, while possible, is not necessary the best solution. I think that's where it is falling apart for you. you are not using file formats that support PAR flags and/ or are not viewing in a tool that can accomodate and compensate for different PARs. Therefore keep the following in mind:

           

          • To preview a correct "unstretched" version, use the PAR preview button at the bottom of the comp viewer panel
          • To produce a correct computer viewable version, use the matching square PAR presets of 640x480 or 720x534 with fit to fill, if necessary.
          • When using native NTSC, make sure you also set the correct PARs in the output module settings so they are embedded in the result file
          • Note, that some output formats and CoDecs do not care for PARs, so don't use them, if you want to retain native NTSC

           

          Your field issues are a whole different matter. Unless you use a high quality tool to interpolate them like RevisionFX' FieldsKit, you eitehr have to accept the combing effect with fully retained fields or lose vertical resolution due to AE only rendering one field at a time. Can't have both. It's an inherent problem with all interlaced footage.

           

          Mylenium

          • 3. Re: Can someone pls help?  Not ustanding import/export aspect
            Mylenium Most Valuable Participant

            Please edit your user name. It goes against forum rules (no advertising or self promotion) and just looks ugly, because it gets truncated. Thank you!

             

            Mylenium

            • 4. Re: Can someone pls help?  Not ustanding import/export aspect
              mongo106 Level 1

              Thank you so much Mylenium.   Your few words have gone a long way and I now understand PAR.   I appreciate the help!

               

              Michael

              • 5. Re: Can someone pls help?  Not ustanding import/export aspect
                mongo106 Level 1
                To preview a correct "unstretched" version, use the PAR preview button at the bottom of the comp viewer panel

                 

                Hehehehehe ok now I definitely feel stupid.   I wish I understood that hours ago

                 

                Michael