[jordanbaucke]

I'm interested in learning what the average "delay" for live-streaming would be? At a high-level RTMP > (Segmenter: EvoStream) HLS > Cassandra < NginX-LUA < HTTP Request (seems to flow model outlined here (From the 2014 World Cup): https://www.nginx.com/blog/globo-coms-live-video-platform-fi...)

I'd assume it's minimum > 20 seconds depending on setup and teardown time for first "chunk" in a sequence to reach cache and be transferred to a user?

[zbobet2012]

TL;DR: The delay is normally a segment length. Somewhere between 2-16s depending on there configs.

Because the system is realtime (live) it _must_ not fall behind live. These systems therefore are always only a single segment behind live. (A segment is an independently decodable chunk of video, usually between 2 and 16s).

Source: I designed the backends, including segmenting, for NBC.

[jordanbaucke]

@zbobet2012 makes sense, certainly, you can shrink the chunk-size down to 2 seconds, I wonder if it's not practical to do though wouldn't the practicality of setting up a setup > teardown of a new HTTP connection, fetching the next chunk, etc. cause inconsistency in completing this procedure by the time a 2 second chunk has played out.

I believe people have used WebSockets to push these segments? Since once you have established one TCP socket connection you don't have to setup a new "session" for each discrete segment?

[kobayashi]

In my experience live streaming events in Canada, the delay is approx 60s behind cable TV. In your estimate, is the Internet broadcaster here using extremely large segments, or is something else at play?

[soneca]

Personal anecdote as brazilian that watched a lot through streaming (both web and app), sometimes comparing with live digital (uhf) open TV and friends updating results through WhatsApp (as each kick result at female football shootout).

The delay would vary between 20 seconds and 60 seconds between streaming and uhf TV (just as an observation, cable TV also has a delay of about 4, 5 seconds comparing to open tv)