12G cabling - test results and a video presentation

I presented a recent Tech Breakfast at Jigsaw24, Golden Square. Here I detail the tests we've done across four cable types and how they perform at twelve gigabits/sec (as per SMPTE 2082-1).

We've recently taken on Leader as a manufacturer of test sets and they excel in several areas - namely UHD/4K/HDR and 12G physical layer measurements. 

 all the specs for SMPTE 2082-1

I got through all the details in the video (below and on YouTube) but you can snag my results here - if you go into the 12G folder you can see the screen grabs for all the eye patterns - the filename number related to the test line in the PDF.  The Powerpoint presentation is in there too; but if you watch the video I cut all the slides full-screen as appropriate.

 The cable types are;

SD05 - Belden 1855; otherwise known as "Image 360"
SD10 - Belden 1694
SD50 - Belden 1505; otherwise known as "Image 1000"
SD73 - Belden 7731 - about the most ungainly cable you can crimp a BNC onto!

After 'Beyond HD Masters 2013' - some notes, cable interfaces and frame-rates.

Today you can buy equipment that works at the TV "4k" resolution which is also referred to as "quad-HD" because it has twice the number of pixels horizontally and twice the number of active lines; 3,980 x 2,160. Blackmagic have already implemented what they call 6G SDi - i.e. 4 x 1.5Gbit/sec 1920x1080 @30FPS (max) with 4:2:2 colour sampling. If you want 50 or 60P at 4:2:2 you'd need 12G and should you want to go to 4:4:4 RGB at 12bit then you're looking at >20G! 

Whilst a coax interface still (just!) works at 6G (and I'd point you towards some research I did in 2009) it seems like single-mode fibre is the only sensible interface that we'll have for synchronous video as 4K starts to be used for live production.

Richard Salmon from the BBC showed that with the huge amount of resolution that 4k brings the human brain recoils if there isn't enough temporal resolution to make moving images look as good as static images. Imagine a rapid pan across the crowd at a football stadium. At sub 100 frames per sec you don't see enough detail in the picture (each pixel is smeared so as to make it look like a much lower resolution image) but when the camera stops the pan you suddenly notice the huge amount of detail. That difference in static and dynamic resolution can, in extreme cases, cause nausea.  With this in mind it seems that the standard for live TV will be 4:2:2 colour encoding at 120 FPS! Anyone for 24Gbit/sec video?! v1.4 HDMI currently only supports sub-8 Gigabits/sec. So - it seems like we're going to have to wait for cable standards to catch up and when it does it'll probably be 9/125µ fibre.

Take this to 8k (which is the second half of the proposed UHD TV standard) then we're looking at 96Gbits/sec! Even current standard fibre struggles with that! So - the other interesting technology that may well form the mezzanine format for moving over cables and networks is pixel-free video; but that's for another blog post!