Which frame rate should I use with Twixtor

[Chris Yiu]

Hi there. I shot my footage in 50fps and I added slow motion effect (50% of the original speed) to the footage with Twixtor in AE. Will the speed of the video be messed up if I choose 30fps for export in the export setting? And what frame rate should I choose for the comp which holds the slow mo footage? Any help is much appreciated and thanks a lot.

[RobShultz]

Adobe does an awesome job with working with different frame rates should be fine with 30fps or whatever frame rate you decide to output to.

[Chris Yiu]

Thanks for your input. It does help a lot.

[Mylenium · Accepted solution]

You totally misunderstand the process. The comp framerate has nothing to do with this. You still use the framerate of the targeted output medium as per specification or whatever the other sources you integrate your modified clip with dictate. The rest entirely depends on your slo-mo settings stricltly on a layer-by-layer basis. Nothing stops you from having a hundred layers with different FPS in a comp. I would strongly recommend to read the Twixtor manual or for that matter some basics on how AE treats time-remapping/ time-stretching/ the Timewarp effect for reference.

Mylenium

[Chris Yiu]

Hi Mylenium. Thanks for your detailed explanation. I would take a look at the manual a bit later. One more quick question. Does it mean the frame rate of the output comp does not affect the speed of the video? Thank you very much.

[Rick Gerard]

You need to spend some serious time learning about frame rates. The frame rate of the comp does not change the playback time of the footage. Put a 20-second clip in a comp that is 30 fps and it will take 20 seconds to playback, you will just see every other frame.  Put a 200 fps shot that is 20 seconds long and is interpreted as 200 fps in a 10 fps comp and it will still play back in real time and take be 20 seconds long.

If you want to change the time of the playback of any footage you have to change the frame rate of that footage. You do that by going to File>Interpret Footage and picking a new frame rate. If the new frame rate does not match the comp frame rate then you are going to get blended, repeated, or missing frames. That is where Twixtor comes in. Twixtor can be very confusing so you need to spend at least an hour studying the manual if you are trying to do significant speed changes to the footage. If you shot at 50 and you want to slow it down and see every frame then and want your comp to be 24 (23.976 would probably be a better choice) and you want to see every glorious frame then interpret the footage as 24 and 1 second of real time will take approximately 2 seconds to playback. If you want to slow down time so that one second of real time takes 10 seconds to play back then you either have to shoot at 10 times the normal frame rate or employ Time Remapping, Time Stretch, or Twixtor in AE go create the frames that are not there and make the motion look smooth.