Frame Rate Variance

The Frame Rate Variance is displayed in the video panel below the FPS value.

(To display these values, from the main menu select Server>Configuration, and click General Settings. The display options are available in the Video Decorations section.)

Comparing Frame Rate Variance

Using the following two images, the frame rate variance is 8.54 and then 0.20.

Symphony stores the times of the last 50 frames, and calculates the variance from them. If you see a high variance, then somewhere in the last 50 frames, a frame did not arrive when it should have. One minute later, at 5 FPS, we received 5 (frames) * 60 (sec) = 300 frames, so this is a new batch of 50, and these ones all arrived when they should have.

Between 10:38:25 and 10:38:35 (a 10 second interval, that is, 50 buffered frames/5 FPS = 10 seconds before first JPEG time), some frames did not arrive in proper time. But, one minute later (see 10:39:12 image), the variance was low, indicating everything was running well.

A high variance could indicate congestion on the network.