In early December, Vimeo took their first step towards becoming a 4K-capable platform by showing off their ability to do UHD/4K encodes on material uploaded in that resolution (only for PRO and Vimeo on Demand users). Here's a clarification from Vimeo on this announcement:

While downloads of 4K source files were always available, we're transcoding in 4K now and allowing downloads of those transcodes. In other words, PRO users upload in 4K and we transcode the video into 4K - and the 4K videos you upload now will be ready when we enable 4K playback on-site.

Although no official announcement has been made yet, it seems like 4K streaming isn't far off either. In a post by Philip Bloom, he showed off some footage from James Miller that was magically streamed in 4K without any notice from Vimeo. After some testing of various encode settings, Bloom and Miller confirmed that Vimeo was in fact streaming in 4K and that a specific encoding process was necessary to make it work.

At the moment there are a number of specific settings you to need to make this work and it only works on new uploads. Anything that’s already uploaded in 4k will need to be re-uploaded to take advantage of 4k streaming. [...] The example films were transcoded/rendered using Adobe Media Encoder in H.264 (.mp4 container) using the 5.2 Profile to allow 3840×2160 resolution to be input. A CBR (constant bitrate ) of around 120Mbps was selected. I have found if the film is longer than 3 mins you can select a lower bitrate for encoding, around 60Mbps. But to play safe keep at 120Mbps if you can afford the upload space and transfer time.

James has also been messing with other resolutions besides just UHD/4K. He's got three different resolutions of the same clip here. As of right now though, he has uploaded two clips that seem to be streaming in 4K. [Editor's note: it's difficult to confirm, but these clips look to be playing back at 4K on a 4K TV. There are not the usual artifacts from 4K upscaling and the clips look great.]

Here are some screenshots from the Vimeo-encoded 4K files (click for the larger files, which have already gone through some compression):

James Miller Fading Light 4K Vimeo Screenshot 1

British Camping James Miller 4K Vimeo Streaming

At this point, we don't know when 4K streaming will be officially enabled on Vimeo, and it's even less clear whether it will be enabled for everybody or just the folks with PRO (or maybe Plus) accounts.

If you're interested in the exact encode settings and upload process that Miller used to make Vimeo magically stream 4K, head on over to Philip Bloom's post to check it out. To see more from James, check out his Vimeo page.

James Miller — 4K Vimeo

Source: James Miller