[webrtc-stats] define an mechanism for setting the trigger duration for a video freeze (#771)

flyingzl has just created a new issue for https://github.com/w3c/webrtc-stats:

== define an mechanism for setting the trigger duration for a video freeze ==
In the  [W3C Identifiers for WebRTC's Statistics API](https://www.w3.org/TR/webrtc-stats/) spec, the logic for marking a video freeze, is defined as follows(see [freezeCount](https://www.w3.org/TR/webrtc-stats/#dom-rtcinboundrtpstreamstats-freezecount)):

1. Calculate the linear average of the past 30 rendering frame durations and label it as `avg_frame_duration_ms`.
2. Calculate the interval between the current two frames. If this value is greater than Max(3 * `avg_frame_duration_ms`, `avg_frame_duration_ms` + 150), it is considered as a freeze.

In situations where the network is good, this logic is quite reasonable. However, in the case of a weak or poor network, the value of `avg_frame_duration_ms` may be larger, for example, **`150ms`**. In this scenario, the freeze trigger value would be **`450ms`**, which may not meet the needs in practice. As generally, **`200ms`** might be considered a freeze. 


So The spec can define an mechanism for setting the trigger duration for video freeze (i.e., when the interval between two frames exceeds this duration, it is recorded as a freeze event).



Please view or discuss this issue at https://github.com/w3c/webrtc-stats/issues/771 using your GitHub account


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Received on Monday, 9 October 2023 03:38:11 UTC