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 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.

https://syncplay.pl/ Send file in advance. No streaming, life's good.

mobile

oh. ... ... ... GL

Owncast is an open source streaming platform. It's great for watch parties and it has its own built-in chat.

You can see a list of public streams in the Owncast Directory

Element, the Matrix app, has video and screen sharing calls. Bonus that it's also e2ee, self hostable, and entirely FOSS

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)

Plex can do it, but I assume you need a Plex Pass. I haven’t used the feature myself.

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 ...

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.

Just share your screen on discord

In the past I used Cytu.be but you'd need to upload video (e.g. to twitch)