Final Cut Pro X: Rate Conform
When working with video clips that have frame rates that are close to being a multiple of the timeline frame rate, but not quite, Final Cut Pro X sometimes speeds them up or slows them down.
When this happens, you will be able to see a section in the inspector showing that its frame rate has been conformed:
This shows that a clip that normally runs at 25 frames a second will be slowed down so that it plays at 23.976 frames per second. It’s playback speed on the timeline will be 95.904%. This means one frame of the clip will be displayed for one frame of the timeline.
Here are the rate conforms that Final Cut Pro X does automatically:
| When you add a clip with this frame rate | To a timeline with this frame rate | It automatically plays back at this frame rate | Speed | % of original duration |
| 23.976 | 24p | 24 | 99.90% | 100.10% |
| 23.976 | 25p/i | 25 | 95.90% | 104.27% |
| 23.976 | 50p | 25 | 95.90% | 104.27% |
| 24 | 23.98p | 23.976 | 100.10% | 99.90% |
| 24 | 25p/i | 25 | 96.00% | 104.17% |
| 24 | 50p | 25 | 96.00% | 104.17% |
| 25 | 23.98p | 23.976 | 104.27% | 95.90% |
| 25 | 24p | 24 | 104.17% | 96.00% |
| 29.97 | 30p | 30 | 99.90% | 100.10% |
| 30 | 29.97p/i | 29.97 | 100.10% | 99.90% |
| 30 | 59.94p | 29.97 | 100.10% | 99.90% |
| 50 | 23.98p | 47.952 | 104.27% | 95.90% |
| 50 | 48p | 48 | 104.17% | 96.00% |
| 59.94 | 60p | 60 | 99.90% | 100.10% |
| 60 | 29.97p/i | 59.94 | 100.10% | 99.90% |
| 60 | 59.94p | 59.94 | 100.10% | 99.90% |
This is a full listing of the combinations where Final Cut Pro automatically changes the speed of a clip. For any other frame rate combnations Final Cut will drop or repeat frames so that they source clip seems to play at its original speed.
For example if you add a 30p iPhone video to a 25p timeline, Final Cut will skip some of those frames every second so the playback speed remains the same and the duration stays the same: a 3 second 30p clip will take 3 seconds to display in a 25p timeline. If that same 30p clip was added to a 48p timeline, then Final Cut will repeat some frames so the playback speed will remain the same: the 3 second 30p clip will display for 3 seconds on a 48p timeline