Dr Jess BirchJul 10, 2024
Looking at the Twitch Enhanced Broadcasting rollout (you encode up to five streams on your local system & stream them all to Twitch, which then sends the requested single stream to viewers rather than transcode at the server), I wonder if we are going to eventually get a situation where you get multi-resolution video encodes. The start of each block decodes to a low res output but extra data add more spatial detail so rather than multiple encodes, there is one with a variable payload size.
Show threadIgnas KielaJul 13, 2024
@shivoa there are some experimental stuff, usually called progressive video IIRC?

But I think it's usually better to negotiate the bitrate for most applications, because digital data transmission is mostly all-or-nothing.

FPV drones use PAL/NTSC because of this, because even if there's signal integrity issues, you still get some picture.
Show threadAlexander MonakovJul 13, 2024
@ignaloidas @shivoa I don't think it's necessarily all-or-nothing. Sure, on the Web we don't have loss-tolerant protocols with embedded error correction (but isn't that related to use of loss as congestion indicator in TCP?), but when the medium is fundamentally very noisy there are various tradeoffs to try before the ultimate fallback to blasting how much of the uncompressed data fits.
Show threadIgnas Kiela
@amonakov @shivoa right, but even the more advanced protocols with ability to specify tolerable loss and stuff like Media over QUIC essentially falls down to a bandwidth negotiation. You could serve progressive video over it of course, but it wouldn't be that much better than what you have with bandwidth negotiation.
Jul 13, 2024 at 12:13pmWeb
Show threadWolf480plJul 13, 2024

@ignaloidas @amonakov @shivoa
ok but even with bandwidth negotiation, wouldn't it be easier for the server to discard some chunks of the stream and send only the low-quality part to low-bw clients, and all of the chunks to high-bw clients?

Then the server doesn't have to transcode, and the total bandwidth from the source to the ingest server is max(qualities) instead of sum(qualities)