If you mean a low resolution, you can use any of several browser extensions (I like Iridium) to automatically "manually" select the resolution right when the page loads for every video, and this will also increase your maximum buffer from 20 seconds (?) to 2 minutes, which is nice if you're on wifi. If you mean on high resolutions the videos still look terrible, that's because the av1 versions of many videos look very bad above 720p on purpose if they're mostly watched in certain countries (can't find the source now, so treat as hearsay) where most viewers are on smartphones. You can mitigate this by going to settings > playback and performance and select "Prefer AV1 for SD."

Thanks for the tips. Will give the AV1 setting a shot. By Iridium do you mean "Iridium for Youtube"? It seems it's not maintained anymore? TBH this functionality was default working on Youtube for me until recently and suddenly stopped. I'm on a 4g based wifi at home (long story) so maybe this is the issue but it 1) only just started happening in the past 2 weeks and 2) really shouldn't be an issue as the speeds are pretty good. Everytime I switch to 1080 or higher even there is no buffering issue at all.

Most frustrating is the YouTube video quality with Chromecast. I can get some 4K to my tiny cellphone, but Chromecast projected to 190" picture on the wall is locked to some unknown SD that is compressed to smithereens making it completely unwatchable.

Are you, by chance, using Brave? I've noticed that recently with Brave as well. Didn't seem to happen in Chrome even when viewing the same videos on the same machine.

Firefox. Dark pattern to get people to use Chrome?

I've also been seeing this in Firefox for the past couple weeks or so.

The video quality will default to "Auto-1080p" or similar but it will be visibly much worse than 1080p quality. Switching to 1080p manually seems to be the only way to get good quality.

This has been the case for as far back as I can remember.

I've had the same experience on Safari—in addition to the issue with Find no longer working in Google Docs (https://news.ycombinator.com/item?id=27351855).

I strongly suspect that at least part of the reason for these is to discourage people from using Google's properties with browsers other than Chrome (whether it was the reason for creating them, or just noted as a benefit for refusing to fix them once they were identified).

I suspect this is the real cause. They did it with search, makes sense they would do it with other areas as well.

They did reduce default quality for corona reasons before, might be the same thing?

It just started happening so I doubt it.