18 Replies Latest reply on Aug 4, 2013 4:27 PM by Steven L. Gotz

    Changing Frame Rates

    SteveC100 Level 1

      I'm working on old 8mm home movies, shot at what I thought was 18 fps and transferred as a tiff sequence. I opened each clip and identified it as an 18 fps source, then cut them into 18 fps timelines.

       

      Now I discover that the camera was really shooting at 16 fps. So I'd  like to change the frame rate of each clip and of the resulting sequences. Can this be done without affecting the existing cut points? I believe that when I tried this in AE, my cuts moved and even ended up between frames. Is something strange like that going to happen here? Anybody have any suggestions?

       

      Thanks for any help you can offer ...

        • 1. Re: Changing Frame Rates
          Jim_Simon Level 8

          The only way I know to correct this is to change the Indeterminate Media Timebase in the Preferences.  But that only applies to new Image Sequences brought in, so you'd have to redo everything.

          • 2. Re: Changing Frame Rates
            SteveC100 Level 1

            My understanding is that the indeterminate frame rate is for clips whose framerate isn't identified via metadata. The system is saying, "If I can't figure out the frame rate, what do you want me to call it?"

             

            The source clips are already identified. I  can select the clip, choose Modify > Interpret Footage, and change the frame rate. But the problem is that I can't do the same thing for sequences. If I select a sequence and choose Sequence Settings, I can't modify it's frame rate -- the field is greyed out.

             

            Maybe there's a way to do this via xml. Otherwise, I don't see how ...

            • 3. Re: Changing Frame Rates
              Steven L. Gotz Level 5

              You can create a new sequence. Then just lasso everything on the original sequence, copy it, and paste it into the new sequence.

               

              I am not certain that will help with the frame rate, but I would think it should.

              • 4. Re: Changing Frame Rates
                SteveC100 Level 1

                What I really want to do is take the 18 fps sequence and play it at 16 fps -- just play it slower -- without interpolating or dropping frames.

                • 5. Re: Changing Frame Rates
                  SteveC100 Level 1

                  Thanks, Steve. Good idea. I will try it and report back.

                  • 6. Re: Changing Frame Rates
                    Steven L. Gotz Level 5

                    Yikes! That didn't work.

                     

                    Give me a few minutes to play with it.

                    • 7. Re: Changing Frame Rates
                      Ann Bens Adobe Community Professional & MVP

                      Interprete the footage to 16 fps.

                      Make a new timeline from one of the clips and nest the 18 fps in this new timeline.

                      See if that is going to work.

                      • 8. Re: Changing Frame Rates
                        Steven L. Gotz Level 5

                        I can't seem to make this work.

                         

                        If you change the interpretation from 18 to 16, then create a 16fps sequence from one of the clips, then copy the entire 18fps timeline over to the 16fps timeline, you need to pull out the end of each clip in the timeline to accomodate the new duration.

                         

                        I don't see a way to do it without manually adjusting each cut by pulling it out to the new duration.

                         

                        I may be missing something.

                         

                        Sorry about this. Can't get it right.

                        • 9. Re: Changing Frame Rates
                          SteveC100 Level 1

                          That's what I was afraid of. But thanks for trying!

                           

                          I think the nesting trick is going to be a problem, too -- I think there will be skipped frames within each clip as PP tries to change the frame rate but keep the same clip durations.

                          • 10. Re: Changing Frame Rates
                            Jim_Simon Level 8

                            My understanding is that the indeterminate frame rate is for clips whose framerate isn't identified via metadata.

                             

                            Exactly, including image sequences.  But there's no way to change it after the fact.  Modify>Interpret Footage takes place after the frame rate has ben set by that preference, so weird things can happen with interpolation you do that.

                            • 11. Re: Changing Frame Rates
                              Steven L. Gotz Level 5

                              I haven't had problems with nice clean changes from 60fps to 24fps using Interpretation. And I did not see a problem moving from 18 to 16. But I did see that the duration of each clip did not change on the timeline. It merely created a handle at the end of the clip.

                              • 12. Re: Changing Frame Rates
                                Jim_Simon Level 8

                                You were going from normal motion to slow motion.  That's a different thing.

                                • 13. Re: Changing Frame Rates
                                  SteveC100 Level 1

                                  Exactly, including image sequences.  But there's no way to change it after the fact.  Modify>Interpret Footage takes place after the frame rate has ben set by that preference, so weird things can happen with interpolation you do that.


                                  What happens when you select a source clip and hit interpret footage and change the frame rate? Doesn't that change the rate that it plays? I realize this doesn't apply to sequences, but it's part of the issue.

                                  • 14. Re: Changing Frame Rates
                                    Jim_Simon Level 8

                                    It does, but in this case it means you're taking an 18 fps clip and playing at 16.  That's not what you want here.  You want PP to see it as a 16 fps clip.  That means importing it with the preference set to 16, not 18.

                                    • 15. Re: Changing Frame Rates
                                      Steven L. Gotz Level 5

                                      Damn it Jim, I am an Engineer not an Editor! Uh. Hmmm. Maybe that isn't quite the right quote.

                                       

                                      You made me doubt myself. So this is what I did.

                                       

                                      I went into After Effects and by animating the source text I easily made a comp that counts from 0 to 17. I used 0 so that the frame number would match the number on the monitor.

                                       

                                      I exported that to 18 PNG files. Imported those into Premiere Pro as a video sequence and interpreted it from 29.97 to 18fps. Dropped it on the New Item button to make an 18fps sequence.

                                       

                                      Played through frame by frame and it looked fine. Interpreted again to 16. Created a new sequence using the newly interpreted 16fps and then deleted the clip from the sequence.

                                       

                                      I copied the first sequence (with a couple of copies of the clip on it) and pasted it in the new 16fps sequence. This did not extend the duration of either clip, so instead of 17 being the last frame, 15 was. So I pulled it out to show all the way to 17. Played though frame by frame. Nice and clean. No interpolation.

                                       

                                      Conclusion, it is OK to change interpolation. It still just plays each frame individually. No fuss, no muss.

                                      • 16. Re: Changing Frame Rates
                                        SteveC100 Level 1

                                        Thanks, Jim! I was going to try this myself. So basically, I change the source frame rate, create new sequence, copy all clips and paste them into the new sequence and then trim every clip to the right a few frames as needed. Not perfect, but a lot better than 'you can't do it'.

                                         

                                        Thanks again --

                                        • 17. Re: Changing Frame Rates
                                          shooternz Level 6

                                          Surely a tiff sequence (individual frames) does not have a frame rate or a source rate?

                                           

                                          The framerate / playback speed can only be "set' by the Sequence setting. eg like a comp in AEFX.

                                           

                                          How are  the sequential tiffs displayed in the Project Bin? (a folder of numerical stills or a single clip?)

                                          • 18. Re: Changing Frame Rates
                                            Steven L. Gotz Level 5

                                            Craig,

                                             

                                            When you change the frame rate of the clip, and it appears as a clip without audio in the Project Panel, it works fine in a sequence of the same frame rate as the one you interpreted it to. If you change it to 16fps and leave it in the 18fps sequence it repeats frames - it doesn't blend them without being told to. Put it in a 16fps sequence that you created from it and it works fine. No frames deleted or blended.

                                             

                                            Now, here is the "bug" in the system.

                                             

                                            When I import the image sequence it always starts as 29.97. For me it does anyway. It might just be that it uses the last project settings I used. I don't know. I know that if I create a project it doesn't ask for my settings aincw I upgraded to CC. When I create a 25fps sequence then import the clip it still comes in at 29.97. I don't see how that is a good idea but that is the way it is.

                                             

                                            So, basically, I am importing as 29.97 regradless of what I change it to using Interpretation. Interpreting to whatever I want, then creating the sequence using the New Item button is the way to go. There are no presets for 18fps or 15fps so the only way it is even possible to create those sequences is from the media. Even the custom settings don't allow just any frame rate.

                                             

                                            It would be nice to be able to change the interpretation, copy to a new sequence, and have the cuts extend to match the new duration. It would be a seldom used feature though, and as far as I am concerned, there are more important things for the programmers to be working on.