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Browser-based, but works on mobile just fine: https://www.watchparty.me
The amount of viewers you can stream to depends on your upload speed and video bitrate. There's a premium version that allows relaying video files via their servers.
It's also open source so you can host it yourself should you want to.
This is just what I needed! Me group has been using Discord for the longest time but it very frequently turns into a 144p stream
This is usually a function that full blown media servers offer.
Jellyfin is the one that jumps to mind with this functionality, however I haven't really this functionality out as of yet.
Jellyfin's watch-together-feature (can't remember the name) worked very well on my local network when we needed it (remember Covid? +__+), so I guess it could also be an option if you do it with Wireguard or something similar.
Ive used it a few times, it works pretty well, the issues I faced were minor and easily fixed with a refresh.
Sadly doesn't work with the android TV app though.
Element, the Matrix app, has video and screen sharing calls. Bonus that it's also e2ee, self hostable, and entirely FOSS
Doesn't Matrix lack audio sharing from the screen? You'd have to route your desktop audio into your microphone, unless that's changed.
Oh maybe. I've never used it tbh, so maybe I'm spreading a bit of misinformation
There actually is! It is still on my list to actually try it out, but it claims to do exactly what you want: https://fileparty.co
Tell me about your experience, once you have used it :)
Unfortunately it is not FOSS, but I believe peer-to-peer (hard to know for sure without the source)
There's https://opentogethertube.com/ but it only works with mp4s not mkvs so you'd need to reencode most files you can acquire from the high seas ...
In the past I used Cytu.be but you'd need to upload video (e.g. to twitch)
Just share your screen on discord
The freest and open sourcest solution
Oops didn't realize what community I was in, my b!
If OP is looking for FOSS I suggest Element for Matrix. You can screenshare on there as well.
Plex can do it, but I assume you need a Plex Pass. I haven’t used the feature myself.
If you have a good internet connection you can just screen share the movie over any messaging app. The delay should be under a second and be in-sync with the audio delay. So no-one gets spoiled. You might receive the reaction of your friend a little late but it shouldn't matter too much.