Re: [whatwg/fetch] Trailer support in the API (#981)

At 25 frames per second, you generate a single video frame at every 40 ms and assume you ship each frame as they are encoded. Large frames may take longer than 40 ms, smaller ones may take a ms or so to transmit depending on the server's network connection. But that is not that important. What is important is the interarrival time of these chunks as they are received by the client. Each chunk has two associated times (t1 and t2). We know the chunk's size and if we know delta t (t2-t1), we can compute the chunk's throughput. But, we know t2 only, not t1 - we can only estimate it [1]. If that estimate is not good, then the computed chunk throughput will be pretty wrong leading to incorrect bandwidth measurements. As a result, your adaptive streaming client will adapt incorrectly (mostly getting stuck at a bitrate lower than you could get otherwise).

What @mlasak is asking for whether there is a way to expose t1 in the API. The info is in somewhere there, it just needs to be exposed.

[1] Bandwidth Prediction in Low-Latency Chunked Streaming talk at https://mile-high.video/files/mhv2019/index.html

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/whatwg/fetch/issues/981#issuecomment-864598282