Keep a stock message on your phone to cut and paste whenever an iPhone user sends you a potato-quality video. This is mine:
Please don’t send video to me via iMessage from your iPhone. In fact, you really shouldn’t send video via iMessage at all. Video sent by Apple looks terrible on non-iOS phones. This is not a shortcoming of other phones, this is entirely Apple’s fault and is their explicit intention. If you want to send a video from your iPhone, you can open the Photos app, tap the share button, and select “share as an iCloud link”. That will enable All users to view your glorious video of your cat/kids/dinner/vacation/rant/whatever in the high resolution that your overpriced phone is capable of. Another option is to send the video using a messaging app such as Signal or WhatsApp. Alternate messaging apps are what most of the world use in lieu of sms/mms text messaging.
This is a form letter response and you will get it every time you send me video from your iPhone via iMessage.
P.S. I love you
It’s GPLv3-licensed and they have some pretty easy documented steps for self hosting. Their github page is linked in the article.The per-user cost is for a hosted solution. Which isn’t to say they’re not going to pull something shitty in the future.