8k output

[Joe Marler]

[Terry Flaxton] “all possible settings there using H265/HEVC seem limited to 4k. Any suggestions to getting an 8k onto the net in 265 ?”

8k HEVC doesn’t seem supported in current versions of Compressor. It is supported in Resolve but since there is no hardware acceleration for 8k HEVC encoding on any current platform I’m aware of, that’s a potential problem. So Resolve will encode it on a 10-core Vega64 iMac Pro (don’t know about other machines) but it takes about 15 min to encode 10 seconds of material.

You could try exporting 8k ProRes and transcoding to HEVC with Handbrake. They seem to have a fast HEVC software encoding algorithm (x265). I did a quick test using the latest Handbrake 1.3.3 and it seemed to work using the “veryfast” encode option.

However comparing that file size to the 8k H264 produced by FCPX, the H264 version is actually smaller. Neither one will play smoothly in Quicktime — even locally. Maybe more encoding experiments could produce a smoothly playable file.

Youtube has some 8k material that actually seems to work in Chrome (not Safari) but right-clicking and picking “stats for nerds” shows a sustained approx 250 megabit/sec streaming rate. That is using Google’s VP9 codec which is similar to H264.

Even if you uploaded HEVC that will be re-encoded on Youtube or Vimeo to whatever their streaming codecs are. During client/server handshake when the connection is established one of those streaming codecs is automatically chosen. So the upload codec is totally different from the streaming codec provided by Youtube or Vimeo.

[Terry Flaxton]

Thanks Joe – sad to say that’s what I expected though I will check out Handbrake – Won der Share (a bad name on Cow hence the syllables) claim 8k HEVC but I can’t find out how in ‘custom’ as it blocks you – and also Vimeo says it does do it but then you’re uploading 80 gigs for 4 mins and anyway I tried a snippet and it comes out at 4k… (seems like it has to be HDR through the chain)

I’ll check out Handbrake but yet again we’re at the limits – Thanks

Made my first video in 1976, A long term programme maker, DP, editing etc – changing with AR/VR/MR media –

[Terry Flaxton]

I cracked it. Very simple in the end – output an 8k file 4 mins at 76 gig. I put to Premier cc2018 then used it’s HEVC output to get 2.67 gig The only issue in all of this is I can only see the quicktime pro inspector that tells me it’s 8k whilst only allowing HD display on my HD screen – so it’s a trust issue. I tried quicktime 7 but it won’t recognise the file (of course ☺ ) so I’m doing an upload of the 8k HEVC file to vimeo which will no doubt squash it to 4k as it doesn’t have an HDR flags which seems to be their additional requirement for 8k upload. I may do a section up to utube to make sure that works but I’m not sue I’ll bother after this as I’ll tell clients to look at the 4k and imagine 8k when we can do it. An Additional question as I only have HD screens and with Quicktime 7 (6 of them so holding on before upsizing to a samsung tv or LG – all of this kit is much more expensive in the UK). I used to check 4k blown up via Quicktime 7. So am I right in I presuming the Quicktime that sits in Catalina will show at 8k if it’s got an 8k screen on the end of the chain – so the attendant question from me to if you know is if you’ve got a 5k screen does the latest quicktime automatically resize to a nearby resolution like 4k or whatever the size of screen it’s dealing with?

Made my first video in 1976, A long term programme maker, DP, editing etc – changing with AR/VR/MR media –

[Terry Flaxton]

oops that was 3.57 compressed – I misread that (at 119 mb) and Vimeo created a 4k version

Made my first video in 1976, A long term programme maker, DP, editing etc – changing with AR/VR/MR media –

[Joe Marler]

[Terry Flaxton] “am I right in I presuming the Quicktime that sits in Catalina will show at 8k if it’s got an 8k screen on the end of the chain – so the attendant question from me to if you know is if you’ve got a 5k screen does the latest quicktime automatically resize to a nearby resolution like 4k or whatever the size of screen it’s dealing with?”

Viewing 8k vs 4k Vimeo and Youtube content on a 5k iMac screen shows there’s more detail visible at 8k. This implies the viewable resolution is not capped at 4k by the iMac 5k screen.

However that is with my face 20″ away from my 27″ screen and using prescription computer reading glasses optimized for that distance.

There is a relationship between screen size, resolution and viewing distance. To see the difference between 8k and 4k on an 80″ screen, you’d need to be closer than about 1.3 meters (about 4 feet) — see below link.

Diagram of resolution vs screen size vs viewing distance, including 8k and above: https://photos.smugmug.com/photos/i-HHkdtSn/0/4e47ce96/X2/i-HHkdtSn-X2.jpg

The playback system would also need reliable 200 mbps download speed, plus the video decoding hardware and software to support that without lag or dropped frames, and for all scene types. Some scene types (ripples on water, camera flash strobes, fireworks, etc) are more difficult decode cases and deficiencies often show up there. So you can’t just give out a URL and assume it will work.

There are several video encoding test cases commonly used in research. I don’t know where you could obtain these at 8k resolution but you could try to find (or shoot) similar 8k test clips, then validate your system end-to-end (inc’l final playback system) before having a client watch your actual material. One example scene is “Ducks Take Off”. This is a compressed Youtube clip, you’d need to obtain the original uncompressed video for each test case. If that sounds like a lot of work, welcome to the bleeding edge — that is the cost of 8k at this stage of development:
https://www.youtube.com/watch?v=WDcf0ri8XUE

Links to additional encoding test material:

https://media.xiph.org/video/derf/
http://ultravideo.cs.tut.fi/#testsequences
http://medialab.sjtu.edu.cn/web4k/index.html