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cta-standards / R4WG20-QoE-Metrics

Issue tracking repository for the R4-Wg20 QoE Initiative
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Metric on buffer fill #15

Closed crittlc closed 5 years ago

crittlc commented 5 years ago

One of the parameters which may give valuable information on A/V streaming QoE is the variation in time of buffer fill, i.e., the amount of data (or the amount of video seconds, i.e., buffered_data_bytes devided by played_bit_rate) currently stored in the client buffer. When this buffer fill becomes 0, player stalls.

So, to complement (and anticipate) the metrics on rebuffering, it would be useful to have also a value of "buffered_video_seconds".

gheikkila commented 5 years ago

How would this metric be used, and by what entity? Note that the scope of the standard is to monitor the streaming sessions, not to actively change or improve the ongoing session.

prasadnadig commented 5 years ago

Relevant to consider; in someways, this is indicative of whether downloads are catching up with playback with the buffer having enough to avoid a stall. I recall earlier working group sessions where playback speed was discussed as that could dictate required buffer fill rate.

mlevine84 commented 5 years ago

We agree this is a useful property, especially for diagnostic purposes, but it does not tie directly into one of the metrics currently defined in the spec. Even though it is useful, we are trying to minimize the amount of properties in the initial version of the spec.