Encoding
30 fps or 29.97? Frame rates for game recordings
For game footage, record and encode at a whole number such as 30 or 60 fps and keep that rate all the way to upload. 29.97 fps comes from colour NTSC television. YouTube asks for video at the frame rate it was recorded at.
Where 29.97 comes from
When colour was added to NTSC television, the frame rate dropped from 30 to 30/1.001, about 29.970 fps. The colour subcarrier frequency had to be built from small whole-number ratios, which set the line rate, and the frame rate followed. The change was 0.1 percent, small enough for existing sets. PAL countries broadcast 50 fields, or 25 frames, per second.
Which rate to choose
- 60 fps for fast games, if the PC can record it. YouTube recommends 12 Mbps for 1080p at 60 fps.
- 30 fps to halve the data while recording and keep files small.
- 25 or 50 fps only to match PAL footage you are editing with. Beepa's FAQ notes some editors treat 25 fps as PAL and 29.97 or 30 as NTSC.
What the frame rate costs
| Frame rate | Bitrate | Per minute of video |
|---|---|---|
| 24, 25 or 30 fps | 8 Mbps | 60 MB |
| 48, 50 or 60 fps | 12 Mbps | 90 MB |
In YouTube's figures, doubling the frame rate raises the recommended bitrate by half, from 8 to 12 Mbps.
Smooth motion
Changing frame rate in an encode duplicates or drops frames, which shows up as judder. Set the editor project and the encoder to the recording's rate. If a 30 fps recording looks jerky, the game probably ran below 30 fps while recording; see Fraps lag and fps drops.