Not everyone uses (nor desires to use) AWS. And I know of no video processing service that does background conversions for display elsewhere other than a YouTube type site that requires the material to be held by them.
I KNOW as an admin I would NOT want to have to set up a site YouTube account and allow end users to upload videos to an account associated with MY username as you then become responsible for the content. Good luck proving that that child porn/snuff film/bomb making how-to that was uploaded to your account wasn't your responsibility, and even if able to prove so, uploading a non-approved YouTube videos that are in violation of YT policies would most likely end up with said Admin account suspended.
TapaTalk used Vimeo for all their in app video uploading for a while. They've since removed it, said they're working on an new solution but as far as I can tell it's not come back though.
The only "easy" solution for direct uploading requires the associated processing via the site itself. This requires adequate storage (for said videos) and adequate processing power for the conversion into the correct format. The format that an iPhone uploads is not the same as an Android, which is not the same as a Windows phone.
I can see there being demand for 3 different products potentially.
* A YouTube integration for smaller communities who want fast, reliable and free/cheap hosting for user vids after the cost of the add on.
* A native built in uploader for self hosted and self processed videos. For sites with sensitive content or admins who are particular about where the content is hosted and can afford the servers to process it. I guess essentially what the gallery does now with ffmpeg, but the ability to upload to posts.
* A dedicated forum video cloud solution based on AWS that can scale, that admins on any hosting package can sign up to and use without worrying about killing their hosting or bandwidth. You pay per how much you use/process, all the video could be managed through an interface so they can be reviewed, moderated, pruned and monetised via pre, mid or post roll ads and user group access.
The increased and continued growth in video content creation and the issue with file size is another big factor in the case for a native mobile app. With a native mobile app you can use the resources and CPU on the mobile device to resize the video before uploading. This is what What'sApp does when you share videos.
This reduces the processing and hosting cost on the forum's end, and also makes for a better upload experience for the user as the upload will be quicker and the post will go live quicker once the upload is complete.
That becomes an additional potential revenue stream too, as you could limit the upload quality to say 480 or 720p by default and only allow 1080p or higher for premium members.