What has changed on YouTube recently?

I have noticed that in the last few days lots of YouTube videos that I used to look at (with Chromium in Raspbian) are no longer accessible. They all say

If playback doesn’t begin shortly, try restarting your device.

Anybody know what is going on?

PS. Following advice found on line, turning off hardware acceleration in the Chromium settings seems to cure it.

YouTube change things from time to time. This is partly to placate the shouty Big Labels, and partly (mostly!) because they want to stick adverts into everything ¹ in order to make money.

These adverts are inserted in-stream by the website and the app(s). Most of the unofficial (alternative) ways of watching YouTube provide the direct video stream, hence no adverts. Additionally, these ways of watching are also closely tied to ways of downloading (which YouTube prohibits). As such, they tweak things from time to time to throw off all of these unofficial ways of watching.

I use NewPipe (on Android) to watch. No adverts, no tracking, and easy to grab a copy of anything of interest.

¹ Did you notice? In 2020 they quietly slipped the “right to monetize” into the Ts&Cs. That means they can, at their discretion, insert advertising into channels that are not marked as “monetized”. And since the channel isn’t being monetized, you won’t see any cut from the advertising revenue. In short, the only way a popular channel owner won’t lose is to insert adverts into everything, which suits them just fine as it’s them slinging the adverts. People with morals will get screwed twice (adverts they don’t agree with and can’t control, and not a single dime for it). Bastards. There’s more than enough unwanted advertising punting crap that nobody wants burning up many megawatts daily, we don’t need more, but it’s their business to extract money from the aether…

usually Youtube is updated then the applications are updated to work with the changes

Well, yeah, they’re hardly going to give advance notice to people using unofficial software.

This time it seems that none of the apps are getting updated.

Change app. NewPipe works fine, and youtube-dl was last updated 2021/06/06 and appears to work, athough YouTube appear to have recently messed around with playlists.

they should embed them in the video stream

Please, just NO.
Firstly, they likely won’t do it as the overheads of muxing in different adverts for different people/regions will be ghastly; and doing that means it would be impossible to pull an ad-free original.

Then they would not have to worry about what application is used to play the video stream

Sorry, no. Thanks to your RIAA they have to make an attempt to use some sort of encryption and encoding for playing copyrighted content. I believe it’s one of the provisions of the DCMA? The fact that the method is lousy and easily broken isn’t the point (look at DVDs CSS!), the point is they have to be seen to be doing something.

Personally I have been looking into alternative video hosting sites

None are as friendly and accessible as YouTube.

Over here, a lot of stuff gets put on DailyMotion.

The problem is a fair few sites have come and gone that promote themselves as “cool ways to share videos with your friends!”, so long as by “share” you understand that it’s whatever is about to be released at the cinema… StageVu, VeeHD, and most of OpenLoad for example.
There’s one still around. I won’t give a link as it looks like what it is supposed to be, but you try doing anything and it will start throwing downloads at you, at which point your antivirus will have a nervous breakdown.

Beyond YouTube, Vimeo, and Dailymotion, I’m not sure I’d make any recommendations at all.

Vimeo – you need Premium ($70/month) if you want to live stream anything. The freebie offering is 500MB/week (5GB total). Basic privacy (public or only me, you need to pay to get private links), and up to 10 videos per day (but note the remarkably low size offerings), and the original source files are deleted after a week if you don’t pay (leaving only the transcoded version). There may or may not be a 720p limit. Vimeo doesn’t actually appear to describe their basic offering, this was taken from other sites.

Dailymotion is another that is hard to figure out. They want to call you a “Partner” (yuck) and the starter level is free. The more advanced also claims to be free, but there’s a button saying “Contact us”. When it comes to file sizes and durations, the help says this is detailled on the upload page. So… <shrug>

YouTube, love it or hate it, pretty much doesn’t care so long as your account is verified and in good standing. A 1.3GB upload? No worries. 2160p? Go for it. Various tweaks afterwards? Subtitles? It’s a bit half-assed at times (Google needs better programmers!) but it generally can be done. If you don’t feel like subbing your own videos, then they’ll usually auto-generate captions in your language…with varying degrees of hilarity.
Pretty much the only thing they outright ban is live streaming from mobile phones for accounts with a low number of subscribers – and this was mostly in response to some <bleeeep!> killing people while livestreaming it. Of course, it’s pretty easy to work around since you can live stream from a desktop machine, so just use a third party app that fakes it.

Let me know if you find anything useful, but I’m not going to hold my breath.

and attempting to suggest that content providers switch to something with more reasonable Terms.

Hosting and provisioning costs money. It seems to me that the sites with moe reasonable terms (Vimeo promises they won’t shove adverts into your videos) expect you to pay for the privilege. As much as we may whinge about YouTube’s excessive advertising, you and your viewers are the product so you don’t need to drop a bag of coin on the table in order to use the services.
I’ve seen a few services launch with a “we’ll give you all this for free” outlook. They don’t tend to last very long. One I recall imploding ungracefully was a service based, I think, in Jakarta and run by an ex-‘nam soldier (American). One of the harddiscs failed, and he posted a message on the user chat forums to say that such-and-such a server had died, and everything on it was lost (because the budget didn’t allow for such things as backups or even a RAID array). The users, predictably, reacted as if God had just wiped the recipe for beer from the face of the earth. He replied “what the hell do you expect for free?” (a lot more sweary!). The next day the chat stuff was a 404. The following day the entire site was a 404. It probably doesn’t help to deal with stuff like that if you are easily upset and have a hair trigger temper. But it does highlight the point that video takes huge amounts of space and somebody, somewhere, will have your video on their harddisc. Altruism only goes so far. Then you’ll be expected to pay in some manner. With YouTube, it’s crappy adverts (or not, thankfully!). Or if you’re dumb enough, their premuim music service that will happily stream and cache the same music videos as the third party unofficial apps. ;-)