Avid Media Composer takes a much different approach when working with mixed framerates than Final Cut Pro or Adobe Premiere Pro do.
Typically, Avid adds some fudge factor in so that mixed frame rate footage matches your timeline settings. For example, you shot most of your film at 23.98, but goofed and shot a scene in 59.94. Avid will modify the 59.94 FPS footage so that the cadence. This is great until you want to work with footage you deliberately want in a modified framerate, like slow motion.
You must import your 720p59.94 slow motion footage into a new 720p59.94 project. Next, you re-open your main 23.98 FPS project and then open the bin containing the footage. Once the bin from the 720p59.94 project is in the 24.98 project, drop the footage in the timeline and promote it in the motion adapter.
The most crucial part is changing the speed in the speed graph to 100% so that you see the speed changes.
Slow Motion in 23.98 FPS Project Workflow
- Identify slow motion media on your media
- Import or AMA your normal framerate media into your normal 23.98 FPS project
- Close that Project
- Create a new project based off of the footage settings, like 1280*720 resolution at 59.94 frames per second
- Create a new bin and call it Slow Motion Footage
- Import or AMA your slow motion media into this bin
- Transcode the footage to MXF media
- Save the project
- Open your normal 23.98 project and open the Slow Motion Footage bin
- On the top taskbar, click File -> Open Bin and navigate to the Slow Motion Footage bin
- Drop your slow motion footage into the sequence when ready
- Modify the playback speed so it plays back in slow motion
- Select the footage in the sequence
- Hit the Effect Mode button in the top left of the Timeline Window
- A Motion Effect Editor window will appear, and next to Motion Adapter click the Promote button
- The Motion Adapter text will change to Timewarp, so click the Speed Graph (One with green person running)
- In the Speed Graph , drag the keyframe down to 100%, or punch in the desired speed in the text field under the Y Axis of the graph
- Congrats, your slow motion footage will now play back in slow motion.