10 Replies Latest reply on Jul 22, 2013 6:41 AM by Rick Gerard

    How best to convert 24fps Image Seq to 29.97fps progressive QT file

    philc452 Level 1

      I have tons of Image Seqs created at 24fps. I need to convert to 29.97fps QT files. Results need to stay progressive...not interlaced. Shots are very short....less than 10secs.

       

      The source material (tiff seqs) is character animation files with alpha...over black (not composited scenes). I mention this because traditional pulldown and frame blend don't look so great as the "ghosted" frames are very obvious.

       

      The best I have achieved creates the duplicated 4th frame, and maintians correct duration, speed and clean frames. But this creates a motion artifact due to the duplicated 4th frame.

      Workflow:

      -Source-24p tiff seq->Interpret 23.976

      -add to render que

      -Render Settings->change frame rate to be 29.97

      -Result->Progressive Frames and correct duration/speed but duplicated 4th frame

       

      What options are there to convert 24p to 2997p while maintaining correct duration and speed? Do I need to purchase a plug-in or can I get good results with AE?

       

      This is not for broadcast...entirely file based workflow....editing/compositing sources in AE/PPro....exporting final files as ProRes4444 29.97p for playback.

       

      Thanks,

      phil

        • 1. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
          Rick Gerard Adobe Community Professional & MVP

          The first question you have to ask yourself: "is the timing critical?"

           

          If the timing is critical the usually the very best way to change 24 frames per second 29.97 is to introduce 3-2 pull down and make it interlaced. The other option, depending on the animation, is two time remap the footage. If your sequences 10 seconds long at 24 frames per second then interpret the footage as 29.97, drop it in a 29.97 Call and then time remap it to 10 seconds. Experiment with some frame blending modes and see how the action looks.

           

          Another other option is to use third-party time remapping software like Twixtor.

           

          The final option, since you are not stuck in the broadcasting world, is to just make your project 24 frames per second. If there is 30 FPS video involved in the project, you usually end up with better motion artifacts by removing frames than by adding them. Without knowing more about your project or actually seeing some of the animation, that's the best advice I can give.

          • 2. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
            philc452 Level 1

            Thanks Rick,

             

            Specs:

            - Final output and edit has to be at 29.97fps and has to be progressive...interlace arrifacts are not acceptable

            - Timing is critical...sometimes need to sync with audio soundtrack...other times shots are so short that keeping origina lduration/speed is desired

            - Clips from existing edited features...not an option to extend shots by going back to orignal sources...or rebuild at different frame rate etc

            - Sources are of many different durations...but generally around 10secs or less...but can be anything really

             

            I am prepping the tiff seqs into QT files for use in compositing and editing. Editing must be done at 29.97.

             

            If I look into Twixter...what version/product would I need just for frame rate conversion?

             

            I guess I am looking for options that can be done in mass without having to check artifacts for each shot after conversion....I have dozens of clips to convert.

             

            phil

            • 3. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
              Rick Gerard Adobe Community Professional & MVP

              BTW, when AE you introduce 3:2 pulldown you get interlaced frames but there are pairs of identical fields and there are no empty lines. Every 3rd frame you end up with a blended frame combining two fields from a different time slice. I woujld seriously consider interpreting the 24 fps renders as 23.976 and then adding 3:2 pulldown at render and then batch removing the interlacing. This will keep your timing if there are no clips longer than 20 or 30 seconds, maintain audio sync, and, when played back at speed, the eye should never see the blended frames. Try a test on your sequence with the most motion and judge the playback in a loop. It will probably be just fine.

               

              Twixtor would do this in one step and may or may not produce better results. It all depends on the animation.

               

              BTW, were you aware that all of the Looney Tunes type cartoons were actually animated 2 frames for 1 cell. IOW, instead of 24 different frames per second, there were only 12. They just shot each animation cell twice.

              • 4. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
                philc452 Level 1

                Ok I'll try the interlace and add 3:2...using upper field I guess?

                 

                What is the procedure to batch de-interlace?

                • 5. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
                  Rick Gerard Adobe Community Professional & MVP

                  Just set up a watch folder for the Adobe Media Encoder.

                  • 6. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
                    philc452 Level 1

                    Will I lose half the vertical resolution when deintelacing?

                    • 7. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
                      Rick Gerard Adobe Community Professional & MVP

                      No. Not unless you do something wrong.

                       

                      A test should only take a few minutes. Interpret your footage 23.976, put it in 23.976 fps comp, set up the render cue with the render options set to add a 3:2 pulldown (your choice of the cadience) and render out your footage to a lossless production codec with an alpha channel.

                       

                      Take a look at the playback in real time. If the motion is good for you then drop that rendered footage in your watch folder and set up the AME to render progressive and render another lossless codec version with an alpha. That's all there is to it.

                      • 9. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
                        philc452 Level 1

                        I've been down this road before and determined there is not a perfect solution. But wanted to follow up with my test results per your suggestions, Rick. using 04:08 test Tiff Seq:

                         

                        1 - interpret 23.976, drop into 23.976 comp...render with 3:2 pulldown added...results in interlaced with blended 3rd frame, 23.976fps...render this clip in AME as progressive 23.976fps..results in duplicate frames thru-out...doubles frames but keeps duration at 04:08 and clip is 23.976...but motion is too stuttery

                         

                        2 - interpret 23.976, drop into 29.97 comp...render with 3:2 pulldown added...results in interlaced with blended 3rd frame, 29.97fps...render this clip in AME as progressive 29.97fps...results in duplicated 4th frame...adds  2frames in duration-04:10.....motion is smoother and duplicated frame not too noticiable..depends on action

                         

                        3 - interpret 23.976, drop into 29.97 comp...render progressive...also results in duplicated 4th frame..adds  2frames in duration-04:10.....motion is smoother and duplicated frame not too noticiable..depends on action (same result as 2 above)

                         

                        4 - interpret 23.976, drop into 29.97 comp...add frame blend...render progressive...results in blended 4th frame..but keeps duration at 04:08.....motion is smoother and blended frame not too noticiable

                         

                        5 - interpret 23.976, drop into 29.97 comp...add advanced frame blend...render progressive...results in artifacts during fast motion..but keeps duration at 04:08.....motion is smoothest and artifacts vary with action...sometimes OK most times not

                         

                         

                        My challange is all these elements are isolated over black so frame blend aritifacts can be very noticable...especially since the clips are many times edited into seqs without further compositing...so viewed over black.

                         

                        Next i have to test with clips that need to sync to audio in PPro 29.97 timeline

                         

                        Generally I think I will probably live with the duplicated 4th frame or perhaps where approriate use the blended frame option

                         

                        Am I missing anything here?

                        • 10. Re: How best to convert 24fps Image Seq to 29.97fps progressive QT file
                          Rick Gerard Adobe Community Professional & MVP

                          I just think you're obsessing over a single blended frame and not knowing or realizing how things look when played back. Step through any feature film played back from a standard video device a frame at a time and you'll find things that are not too sharp, frames with rough edges, and segments with temporal judders in some of the motion. You have to know when to accept the moving image as acceptable. The human eye has limitations. The brain makes compensations when it perceives motion. Any element in a scene that moves will strobe or judder if the frame rate and the speed are synced.

                           

                          If you take one of your re-timed animations and look at it at full resolution on the device that is going to be the primary one used for playback and the motion is acceptable, you're done. If you have judders in the motion your only options are to change the speed or add more motion blur. That's just the way it is.