4K Ultra HD video delivers stunning beauty and resolution. But like most new technology, it comes with challenges as well.
For starters, enormous bandwidth (10 Gbit/s) is required to deliver 4K video. This places unprecedented demands on distribution infrastructure. So, how can you ensure flawless implementation for your clients? By knowing how to design 4K distribution systems that address these five challenges:
- Mismatched resolutions
- New frame rate considerations
- Signal integrity issues
- New cable length restrictions
- Source/display compatibility
Manufacturers of 4K sources and displays must take a holistic approach to testing their products to ensure that they are up to
the challenges of an integrated 4K system, liberating system designers and integrators from having to take on this daunting
4K technology overview
The term “4K” is used generally to refer to video signals with a horizontal resolution on the order of 4,000 pixels. Previous generations
of video resolutions were described by the vertical resolution (e.g., 1080p refers to a signal with 1080 vertical lines). Had the naming
convention for SD and HD been used, 4K video might instead be referred to as “2160p”.
There are also an increasing number of “tweener” devices that fall between 1080p and 4K resolution. Even if a given system is not
being designed for 4K content, hardware designed for 2K signals will not carry these higher resolutions
Challenge #1: Mismatched resolutions
720p, 1080i, and 1080p video all share the same aspect ratio – 1.78:1 (16:9). Since essentially all sources and displays have used
this aspect ratio, we’ve seen an era of relative simplicity. There’s been no need to make accommodations for various aspect ratios for a
number of years. With 4K, that all changes because it presents the challenge of managing two different standard resolutions
3840×2160 , commonly referred to as Ultra HD, is precisely four times the resolution of 1080p, resulting from doubling both the
horizontal and vertical pixel count of 1920×1080. Therefore, it has the same aspect ratio as HD – 16:9. Most, but not all, 4K display
devices have a native resolution of 3840×2160.
4096×2160, commonly referred to as 4K DCI, is used in movie production and exhibition in commercial cineplexes. There are some
display devices with a native resolution of 4096×2160, but it is not as common as 3840×2160.
Many 4K cameras and source devices can be set to either of the two resolutions. Veteran AV professionals will recall the SXGA computer resolution of 1280×1024, which had a non-standard aspect ratio of 5:4 when nearly every other signal was 4:3. This led to similar problems – displays and sources had to be carefully matched and correctly configured in order to display all of the information without unwanted cropping or stretching.
…To be continued, OneTouch Automation
Credit: Crestron white paper, “Challenges of Distributing 4K Video”