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Feb. 1, 2022 - Resolution is hard to see. When you watch a movie or a TV show, you might notice their sizes are different. What you are witnessing is the change in aspect ratio. The resolution or the number of height and width pixels on the screen is not the same as the aspect ratio. However, aspect ratio and resolution are related to the image height and width, and changing one changes the other, so it's an easy way to show resolution change. Common resolutions like 1080p, 4K, and now 8K are all the same aspect ratio but different pixel amounts, and it's not easy to see changes between them because pixels are tiny. Still, sometimes it's noticeable when resolution dips extremely low while streaming shows or movies over wifi.

Why 5K and 10K?

5K and 10K are video resolutions too. They have the same height of 4K and 8K, respectively, but they are wider for ultra-wide movies and gaming. 5K is a popular resolution for computer monitors because of the extra screen real estate while working and gaming. Bullet Train 5K HDMI Cables support the 5K and formats for ultra-wide monitors. In HDMI, it's important to remember that the higher the screen pixels are, the higher the required HDMI bandwidth needs to be. 5K resolutions have some tradeoffs for the additional bandwidth requirements, and 10K is twice the resolution of 5K and is only possible with much higher bandwidth.

Importance of HDMI Bandwidth

If we talk about resolution, then we need to talk about bandwidth. The resolution of a video signal is only one part of what contributes to the overall bandwidth of an HDMI signal. There's also refresh rate or frames per second, color bit depth, and chroma subsampling. By adding these together, we can calculate the bandwidth of an HDMI signal. Why is this important? HDMI signals can have a variety of different mixtures of these core elements. You might see some signal combinations more often because they maximize the visuals without sacrificing quality. For example, the combination 4K 60hz 8bit 4:4:4. This combination makes the best picture for an HDMI 2.0 standard aspect ratio signal at 18Gbps. If we were to increase the 4K to 5K, that would go above 18Gbps, and that's in HDMI 2.1 territory. The truth is, there is a lot of flexibility in what HDMI signals are possible, but many are not very practical. So it's beneficial to know how to calculate bandwidth to make the most out of the limitations in the HDMI specification, especially as we transition into HDMI 2.1.

HDMI Spec

HDMI 2.0 and HDMI 2.1 are different versions with different capabilities. For the moment, let's stick with HDMI 2.0 because it's more straightforward. It has a total bandwidth of 18Gbps. We get this number by combining the three 600MHz data rate channels in an HDMI 2.0 cable. Without going too in-depth about data rate calculation, we take the number of vertical pixels, horizontal pixels, bit depth, and frame rate and multiply them together to get a rough estimation of the total bandwidth of an HDMI signal. HDMI 2.1 adds a data channel allowing bandwidth up to 48Gbps, allowing for more combinations in resolutions than ever before. We can even go beyond 8K to 10K for ultra-wide monitors. You can also use an HDMI bandwidth calculator to play around with these different values. A calculator makes bandwidth calculation easy, but keep in mind that it's not exact.

Bullet Train 5K HDMI Cables goes beyond the typical standard formats of 1080p and 4K by supporting all format combinations within the 18Gbps HDMI 2.0 specification, including 5K. Bullet Train 10K HDMI Cables support all combinations within the 48Gbps HDMI 2.1 specifications, including 10K.