Thanks!

Any idea what Firefox is waiting for? To me those lines I quoted seem entirely arbitrary, and a skim through bugzilla didn't help.

I wouldn't say I'm done evaluating it, and as a spare-time project, my NVR's needs are pretty simple at present.

But WebCodecs is just really straightforward. It's hard to find anything to complain about.

If you have an IP camera sitting around, you can run a quick WebSocket+WebCodecs example I threw together: <https://github.com/scottlamb/retina> (try `cargo run --package client webcodecs ...`). For one of my cameras, it gives me <160ms glass-to-glass latency, [1] with most of that being the IP camera's encoder. Because WebCodecs doesn't supply a particular jitter buffer implementation, you can just not have one at all if you want to prioritize liveness, and that's what my example does. A welcome change from using MSE.

Skipping the jitter buffer also made me realize with one of my cameras, I had a weird pattern where up to six frames would pile up in the decode queue until a key frame and then start over, which without a jitter buffer is hard to miss at 10 fps. It turns out that even though this camera's H.264 encoder never reorders frames, they hadn't bothered to say that in their VUI bitstream restrictions, so the decoder had to introduce additional latency just in case. I added some logic to "fix" the VUI and now its live stream is more responsive too. So the problem I had wasn't MSE's fault exactly, but MSE made it hard to understand because all the buffering was a black box.

[1] https://pasteboard.co/Jfda3nqOQtyV.png