Editor’s Note: This content is contributed by Amanda Emerson, Technical Marketing Specialist - Pro AV, Broadcast & Consumer.
8K Bandwidth Bottleneck
Audio/Video (AV) interfaces are an integral part of any display system as they transfer the data required to stream content, play games, and show high-quality images. To the end-customer, they don’t appear to change, but these interfaces are continuously evolving to keep up with the latest display standards. Now that systems are moving from 4K to 8K (and beyond), they are handling more data than ever before, and standards are evolving to support that.
At 33 million pixels, 8K is four times the size of 4K, and 16 times that of 1080p. This means that 8K technology can deliver sharper and more detailed images than ever before, but this also increases the bandwidth requirements. For example, a 4K HDR stream (30 Hz, 4:4:4 color) needs approximately 9 Gbps, meanwhile 8K with the same qualities needs nearly 4 times as much. This puts a lot of pressure on the connectivity. However, not just any interface can handle these enormous amounts of data, and it is crucial to have connectivity options that evolve with, and can support, the newest video formats (such as 4K120 and 8K).
Connectivity enabling 8K
HDMI™ (High-Definition Multimedia Interface) has long been the go-to standard for connecting AV devices, and it has evolved significantly to keep up with the growing demand for 8K content. The latest iteration, HDMI 2.1, can support 8K resolution at 60 frames per second and offers uncompressed bandwidth of up to 48 Gbps. This is a substantial leap in bandwidth (the previous version, HDMI 2.0, only supported up to 18 Gbps) which enables the transmission of uncompressed 8K video, ensuring a crystal-clear viewing experience. HDMI 2.1 also offers features such as Dynamic HDR, which allows for enhanced contrast and more vibrant colors, and Variable Refresh Rate which minimizes screen tearing and input lag for gaming. All of these come together to create a more immersive 8K experience.
Figure 1: Bandwidth capabilities of HDMI versions
Like HDMI, DisplayPort™ has also increased support for 8K with the newest 2.1 version. Now with a bandwidth of up to 80 Gbps, DisplayPort can transmit uncompressed 8K content at higher refresh rates up to 120Hz. This enables smoother motion and reduces motion blur which is particularly beneficial for gaming or live sports. DisplayPort 1.4 is very capable as well, at around 25.92 Gbps it can support 8K at 30 Hz.
The main difference between HDMI and DisplayPort really boils down to the market. HDMI is solidly entrenched in the consumer electronics market, being the interface of choice for television sets, video cameras and nearly all consumer living room equipment. However, in the PC market, things are a little different. HDMI is probably the most-frequently used video interface, but DisplayPort has very strong support, because it shares the same transmitter/receiver PHYs as USB and other PC interfaces, and even the same USB-C connector. In most cases, developers will choose their interface based on the displays or markets they intend to support. An important difference, however, is that applications for gaming and PCs strongly prefer 4:4:4/RGB transmission, whereas video-centric applications historically prefer YCbCr transmission because compression is very important for widely distributed video. These CODECs typically compress and distribute video in the 4:2:0 format, which reduces bandwidth by 50% and offers significant cost savings throughout the equipment chain. Because of these roots, HDMI 2.1 was designed to transmit 8K60 in 8-, 10- or 12-bit 4:2:0 with no loss of quality. While DisplayPort can do the same, it’s more often used in applications where 4:2:0 is unsuitable, such as displaying PC applications that use text or spreadsheets, or video game content which is natively rendered in RGB space.
No matter how you choose to support 8K in your designs, AMD can help fulfill your needs. With our 8K-capable IP subsystems for DisplayPort and HDMI, you can build your devices knowing they will be ready for the upcoming video standards. Add our video IP toolbox, and you can now stop worrying about the interfaces, and focus on your multimedia design. And when you get home and switch on your gaming PC, know that we also offer leading-edge Radeon™ RX7900 XT graphics card supporting DisplayPort 2.1 and ready for next generation displays. and ready for next generation displays.
For more information, please take a look at our AV connectivity page or contact our sales team for further details on IP and pricing.