Understanding 4K & Necessary Data Rates
4K has made some hefty promises to provide better detail, texture, clarity and resolution by quadrupling the number of pixels being delivered. Also known as ultra-high definition resolution, 4K presents four times the picture resolution that standard high-definition resolution offers.
Although displays and technology already exist to support 4K, the lack of 4K content and programming prevents it from permeating the market (although 4K displays can improve the look of standard high-definition content – not just ultra HD content). Most 4K displays and panels are larger in size (at least 55 inches) because the benefits of ultra-high def resolution are less visible on smaller displays.
As it becomes more widespread, 4K will be beneficial across digital cinema, TV, gaming, the internet, and commercial applications (video projection, digital signage, etc.).
Translating to a resolution of approximately eight million active pixels (4096 pixels wide by 2160 vertical high), 4K is delivered in an uncompressed format.
This uncompressed format requires more bandwidth than traditional high-definition. Table 1 below illustrates the data rates that are required to support 4K resolution for different color options at 60 frames per second. At 30 frames per second, the bandwidth requirements are halved.
Suitable infrastructure is also necessary to deliver 4K resolution, including systems that are designed and engineered to handle new frame rate considerations, mismatched resolutions, and source/display compatibility.
Another factor to consider with 4K is its required data rate. To support ultra-high definition resolution and maintain color information, higher data rates are needed as shown in Table 1. The HDBaseT connectivity standard has yet to catch up; it supports HDMI 1.4, not HDMI 2.0. HDBaseT is able to support 4K under certain conditions, but some features will be missing. HDMI 1.4 currently operates at a 10.2 Gbit/s data rate; HDMI 2.0 operates at up to 18 Gbit/s data rate for the highest 4K resolution and color depth. It is possible that a new-generation HDBaseT chipset will be required to support HDMI 2.0 capabilities. For now, many manufacturers are introducing HDBaseT products that can support 4K video within HDMI 1.4.
Due to bandwidth requirements, the industry hasn’t agreed on which cabling options are best suited to deliver 4K signals over longer distances. Signal integrity may be a major issue for proper 4K connectivity; noise interference and increased distances can impact signal quality.
The HDBaseT Alliance indicates that shielded Category 5e and Category 6 cabling will support 4K video, but other vendors state that better cabling is needed (for example, Category 7A). To find the true answers, further research and study are essential.
Belden hopes to verify these claims by doing additional testing in our own labs using different HDBaseT equipment offering 4K capability, along with different cable designs, including shielded Category 6, shielded and unshielded Category 6A, and Category 7A cables. As this testing is completed, we will keep you updated on the findings.