We recently had a customer who wanted to choose the “best” frame rate for his encoded content.
To that end, his goal was to crank up the frame rate as high as possible. He used Kinoma Player’s Performance Test feature on one of his videos and concluded that the best frame rate for encoding for his Treo was 18 FPS (frames per second).
Unfortunately, there are a couple of incorrect assumptions in there:
- That the result of a Performance Test on one piece of content is applicable to other content
- That when it comes to FPS, “more is better”
Using the Performance Test feature
The Performance Test feature gives you the average maximum frame rate possible with the current video. What it doesn’t do is tell you what would be the “best” frame rate for the current video.

Even though this video has an average maximum frame rate of 54.1 FPS, it needed to be encoded at 15 FPS in order for the most challenging-to-decode parts to play smoothly on a range of devices.
Also, this feature isn’t meant as a predictor for how another video will perform. Similar types of video encoded using the same encoding parameters should show comparable results, though.
Choosing a frame rate
Here’s the secret: For smooth video, always use a frame rate that’s a sub-multiple of the source frame rate. In other words, choose a frame rate that divides evenly into the frame rate of your source.
Why? Imagine 30 keys on a piano, representing one second of source video. A frame rate of 18 FPS is like trying to play 18 of those keys if they were spread out across the same space. At first, your finger will line up with the first key — so far, so good. But then your finger will hit a combination of the 1st and 2nd key, then a combination of the 3rd and fourth keys, etc. It would sound pretty horrible, and the equivalent in the video world is stuttering.
For 30 FPS video — NTSC video is technically 29.97 FPS, but it’s generally acceptable to round it up when encoding — good choices include 30, 15 and 7.5 FPS. 15 FPS is a great starting point.
A frame rate of 7.5 FPS seems a bit crazy, doesn’t it? But a frame rate of 7.5 FPS doesn’t mean that half-frames are being encoded. Since 30 divided by 7.5 is 3, it simply means that every third frame is being encoded.
And knowing is half the battle
Now that you know how to choose frame rates, be sure to check out the Kinoma Forum if you have any additional questions about encoding content for Kinoma Player.