The totalSquaredInterFrameDelay property of the RTCInboundRtpStreamStats dictionary indicates the sum of the square of each inter-frame delay between consecutively rendered frames. It is recorded after each frame is rendered.
The inter-frame delay variance be calculated from totalInterFrameDelay, totalSquaredInterFrameDelay, and framesRendered, according to the formula: (totalSquaredInterFrameDelay - totalInterFrameDelay^2/ framesRendered)/framesRendered.
Note: The property is undefined for audio streams.
A positive number.