Yeh, lots of sites attribute it to Apple. This is from Adobe's website: While HEIC has grown in popularity due to being Apple’s standard file format, the Moving Picture Experts Group (MPEG) developed the original HEVC and HEIF technologies. Apple previously adopted MPEG’s Advanced Audio Coding (AAC) standard for iTunes, and newer iPhones started using the HEVC/H.265 video format in the mid-2010s. So it was the natural next step for Apple operating systems to move to HEIC files in 2017 as part of the iOS11 and macOS High Sierra updates. Other sites also credit MPEG for developing the standard, while pointing out that Apple has put it front & center in the public arena. edit to add: I was wrong to ascribe HEIF to Apple. It looks like both formats are developed by MPEG.
Ken, I have a 3-min video file MP4 that I tried to upload but got error message about the extension not acceptable. What extensions are available for short video files?
Some forums permit direct upload of videos. Others (like this one) require that you upload your file to a file sharing website, then paste a link to your file. If you have a FaceBook, You Tube, Vimeo, LiveLeak, Meatcafe or Vimeo account, you can upload your video there and then directly embed it rather than just providing a link to it, depending on each hosting service's limitations.
You can upload files (as specified) to the forum here, but readers would have to click on them in order to access them. For videos to be viewable from the post itself, it would have to be uploaded to one of the following: Dailymotion Facebook Liveleak Metacafe Vimeo YouTube