12 Replies Latest reply on May 16, 2011 7:29 AM by Dave LaRonde

    24p --> 29.97i in AE

    ColtonVideography.com Level 1

      Can After Effects convert a 1080p23.976 frame rate to 29.97p or 60i? I want to convert the 1080p23.976 for broadcast. Can AE introduce the pulldown to do this? Please note that I'm using CS4.

        • 1. Re: 24p --> 29.97i in AE
          Rick Gerard Adobe Community Professional & MVP

          Yes. The basic info is in the help files. You do the conversion in the Render Settings. That's where you'd separate fields and introduce 3:2 pulldown.

          • 2. Re: 24p --> 29.97i in AE
            Dave LaRonde Level 6

            I already know how to add pulldown -- it's actually darned easy -- but after searching for the instructions on how to do this on AE's Online Help, I found Adobe's instructions more than a little Byzantine.  I suppose if you're a programmer used to writing goto statements into your code it's just fine, but if you're a schlub like me trying to get a job done, it's a pain.  So here's the Cliff's Notes version of how it's done:

             

            • Your 1920x1080, 23.976 video should be interpreted with a field order of NONE.  It is doubtlessly Progressive Segmented Frame, which is video engineer jargon for two fields that behave like a complete frame.
            • Drop that footage into a 23.976 comp of the proper H&V resolution & pixel aspect ratio.
            • Add the comp to the Render Queue.
            • Do your Output Module setup.
            • In the Render Settings, select your field order: Upper Field First.  1080 video is Upper Field First.
            • Click on Add Pulldown.  You'll see the five different phases of the 3:2 pulldown cadence.  Pick one.  I'm lazy, so I pick the first one.  You'll note that the frame rate has changed from 23.976 to 29.
            • Save the project and hit Render.
            • View your rendered 1080i 29.97 (aka 60i) video with satisfaction.

             

            That oughta do it.

            • 3. Re: 24p --> 29.97i in AE
              ColtonVideography.com Level 1

              I'm still getting interlacing artifacts (jagged edges every few frames) is this just how it works and I'll have to live with it?

              • 4. Re: 24p --> 29.97i in AE
                Dave LaRonde Level 6

                Time for a little Television Basics 101:

                 

                An HD picture at 1080 is interlaced for broadcast.  At 720 it can be progressive, but at 1080 it's interlaced.  Upper field first.  If you followed the steps outlined above, you have successfully added 3:2 pulldown back into 23.976 progressive video, creating a properly interlaced 1080 picture.

                 

                You now need to look at it on an HD video monitor and not a computer monitor.  Computer monitors can't display interlacing properly; they're progressive only.  If you're serious about producing HD video for broadcast, it's time to get a video monitor and the equipment that will display the video properly from your NLE.

                • 5. Re: 24p --> 29.97i in AE
                  mikerobertchalmers Level 1

                  It might be moot now, but Andrew Kramer wrote a converter that is free and easy to use in AE.

                   

                  You can get it here: http://www.videocopilot.net/tutorials/frame_rate_converter/

                  • 6. Re: 24p --> 29.97i in AE
                    ColtonVideography.com Level 1

                    When using his converter to (try to) go from 23.976p to 29.92p, the video ends up being 24 seconds long instead of 30. I'm confused...

                    • 7. Re: 24p --> 29.97i in AE
                      mikerobertchalmers Level 1

                      How very strange. I'm no expert here but have you tried posting on the forums there?

                       

                      http://www.videocopilot.net/forum/viewforum.php?f=15&sid=b62ae57028f94feb6be3d8a6d60bd5df

                      • 8. Re: 24p --> 29.97i in AE
                        ColtonVideography.com Level 1

                        No I guess I can try that. Using that video copilot tutorial the sequence AE makes when you drop the footage on the new comp button is 24 seconds long.

                        • 9. Re: 24p --> 29.97i in AE
                          Crafaldar Level 1

                          Hello,

                           

                          that's the way to go to use 3:2 pulldown, we've doing it for years for NTSC with no problems. But we're now working for some HD projects, and were asked to interlace to HD 29,97fps from a 23,976fps project. The problem is the reference the client sent (so we know how he likes to recieve his projects) has every frame interlaced, like a 3:3 pulldown if that's the name for it. That should be 1080/59.94, but if you do a 3:2 pulldown, there aren't 59,94 fields because there are some frames that are progressive. I didn't know there was a pulldown with every frame interlaced.

                           

                          So the problem is that when I export using this good ol' settings i can't get every frame interlaced, because of the 3:2 ratio. Until I read this post I was unsure if my interlace would work (can't monitor HD yet). But if you say it works that way I believe in your experience. The thing is, I might have to render in 29,97 with every frame interlaced, AE doesn't seem to have that option.. so how could one render with every frame interlaced to get true 1080/59.94?

                           

                          Thanks a lot!

                          • 10. Re: 24p --> 29.97i in AE
                            Rick Gerard Adobe Community Professional & MVP

                            When using his converter to (try to) go from 23.976p to 29.92p, the video ends up being 24 seconds long instead of 30. I'm confused...

                            Haven't used the convertor but it makes sense that if you change interpretation the length of the footage will change.

                             

                            If you drop a 24FPS comp in a 29 fps comp the length in seconds won't change, but you'll end up with some frame doubling.

                             

                            The best way to change 24fps footage to 29.97 is to render the footage choosing field render and and some cadence of 3:2 pulldown in the Render Settings. Just make sure that you've got the field order correct for your intended output.

                             

                            Edit:

                             

                            Ok, I took a look at the tutorial and the efx preset. I'm not sure I'd ever have a use for it because it's a workflow that I never have used. I'm also not exactly sure what you're trying to accomplish. I can tell, though, by your post, that you're not following the procedure correctly. You've confused the target frame rate and the source frame rate and the interpretation. All the preset is doing is adjusting the speed of your re-interpreted footage so that the time is correct. His expression is sound. If you have your original footage that's 23.976 and you're going to 29.97 then you need to interpret the footage as 29.97, which is going to make it play faster so that it ends sooner. Using the fxx preset you can then speed it up by placing the original frame rate 23.976 in the Actual Source frame rate value, setting the target frame rate of 29.97 in the Target frame rate slider which should give you a 79.98 value in the Frame Rate Warp value (it's pink).

                             

                            This will slow down the clip so that it takes 30 seconds to playback.

                             

                            This isn't necessary at all to produce an interlaced output for broadcast from 24P footage. If your footage is actually 24P, then just put it in a 24P comp (23.076) then open up the Render Settings panel and Turn On field rendering and add any of the 3:2 pulldown cadences you want. You're done and it will look exactly like film transferred to tape, and you won't be saddled with the long render times that you'll get using the Timewarp (Renamed FrameRateWarp by Mr Kramer). I'm not sure that you would see any difference in the output. I'd have to run some motion artifact tests to find out.

                             

                            You could accomplish the same thing by simply dragging the speed slider in TimeWarp to the appropriate value to make your footage the correct length. All the effect preset is doing is making the calculation for you with an expression.

                             

                            Edit:

                             

                            One more thing: You mentioned in an earlier reply that some of the interlaced fields were progressive and some were interlaced. That's the correct answer. Your original 24P footage is converted to 2 fields from frame 1, they are identical to so these two fields (or first frame) are progressive, then 2 fields from frame 2 (which are also identical, therefore progressive) then one field from frame 2 and one field frame 3 (which are interlaced because each field is a different moment in time) which gives you your weird interlacing artifacts. That's what film transferred to tape looks like if you step through it one frame (two fields at a time). I never liked the look so back in the day when I shot a lot of TV commercials on 35mm film I ran the camera at 29.97 fps so we didn't have to transfer with 3:2 pulldown. In those days, the late 70's through the mid 90's, most major advertising agencies that I shot for specified that we would run the camera at 29.97 to avoid the 3:2 pulldown motion artifacts. Then for a while, when we first started experimenting with trying to make video look more like film, folks were intentionally adding 3:2 pulldown to their projects. Now that there are true progressive displays and DVD and BluRay players that will actually playback progressive footage, there is little reason to worry about the 3:2 pulldown problem unless you're delivering to someone that only has the capability of broadcasting or playing back 29.97 NTSC footage.

                             

                            BTW, this problem and all this monkeying around only exists in countries where NTSC was the broadcast standard. No similar problem exists in PAL land.

                            • 11. Re: 24p --> 29.97i in AE
                              Rick Gerard Adobe Community Professional & MVP

                              As a test of the worst case motion artifacts I created a simple shape, then over 1 frame rotated the shape 90º in a 24FPS comp. I then rendered the frames as 23.976 progressive and as 29.97 fps interlaced with pulldown. I then dropped the 24p rendered footage into a new comp, followed Mr Kramer's instructions and used TimeWarp to see what kind of motion artifacts would be introduced by this radical repositioning of my shape layer in the same frame.

                               

                              The top of this test image shows the crossed field where the first field comes from frame 2 and the second field comes from frame 3. It's exactly as I expected, and when played back at speed your eyes can't detect the funky frame.

                               

                              The bottom of this test image shows the same frame using Mr Kramer's technique. In this case TimeWarp was trying it's best to interpret a new frame based on the radical change in position. When played back at speed, this frame looks funky.

                               

                              motionArtifacts.png

                              I'm pretty sure that the TimeWarp method used in Andrew's ffx preset does a fine job when the motion on the screen is normal, but I'm not convinced that it produces the best results when things are moving quickly. One last thing, the render with 3:2 pulldown introduced for my 20 frame sequence took about 20 seconds. The render for the sequence using the Animation Preset took about 20 minutes.

                              • 12. Re: 24p --> 29.97i in AE
                                Dave LaRonde Level 6

                                Crafaldar wrote:

                                that's the way to go to use 3:2 pulldown, we've doing it for years for NTSC with no problems. But we're now working for some HD projects, and were asked to interlace to HD 29,97fps from a 23,976fps project. The problem is the reference the client sent (so we know how he likes to recieve his projects) has every frame interlaced, like a 3:3 pulldown if that's the name for it. That should be 1080/59.94, but if you do a 3:2 pulldown, there aren't 59,94 fields because there are some frames that are progressive. I didn't know there was a pulldown with every frame interlaced.

                                 

                                I'm scratching my head over what this  client actually wants, because what you've just described is normal 59.94i video.  You'd have to use frame rate conversion software to convert the 23.976 footage to 1080 59.94P... and then add the interlacing to get it to 59.94i....

                                 

                                ....which sort of defeats the whole idea of shooting at 23.976, no?