There is an option to 'upgrade' your video to 1080p on Vimeo, but I am very curious what effect switching 'HD' on has if you don't upgrade your video. My understanding is that the HD switch always changed the resolution to 1080p. Am I wrong?
Also, is it necessary to upload a 1080p source video for Vimeo to 'upgrade' your video, or does Vimeo resample your 720p video up to 1080p?
A lot of confusion as to exactly what is happening behind the scenes when you upload to Vimeo or YouTube.
Best Answer
I would assume it is necessary to have a 1080p source as they cannot upscale to a higher resolution unless they had access to the original source files and could re-render the video in 1080p.
Vimeo will switch to 1080p if it is available, and if the Vimeo user is a paid member, or have upgraded their video. If they did not there usually is not an HD option. In the case that there is one for some reason than 720p would be displayed.