While trying to reduce the video latency for a WebRTC communication, I measured the delay between the video capture and the video display.
To prevent measuring latency involved by WebRTC, I just used getUserMedia and an HTML video that displayed the stream.
I did it by displaying a timestamp every frame (using requestAnimationFrame), recording my screen with a USB camera and taking screenshots where both the video display and the displayed timestamp where visible.
On average, I measured a delay of ~150ms.
This must be an overestimation (due to requestAnimationFrame time between calls), however the minimum measure I made is around 120ms, that still a lot.
Now, is there a way to reduce this delay between the video capture and the video display ?
Note:
- I tried using another video lector (window's built-in lector), and the measure were really close (average delay about 145ms)
- I tried another video device (my laptop webcam with a mirror), and the results are less close but still elevated, on my opinion (average delay about 120ms)