# Technical hurdles for high-frequency video output implementation

I'm wondering if HDMI or DVI formats support the display of input signals at high frequency > 240Hz. Most current TVs only display high frequency video from signal interpolation, but only capture input signal at 60Hz.

If a team wanted to develop or tweak a video display to output signals with high data framerates, where would it need to begin? I know the question is a bit vague, but I'm just trying to understand as a non-expert the high level features of the technical problem

• What will you do with the transmitted video signal? – apalopohapa Nov 23 '13 at 1:37
• What's the aim of this? 60Hz frame rate is pretty damn smooth, 240Hz would only seem to give benefit if you were making a TV for hummingbirds? – John U Feb 21 '14 at 9:49

What I've seen normally done is to use multiple lines. For example, high-end high definition video cameras (like the Sony F55) use multiple 3G-SDI lines. Even though in those cases it is usually for very high resolution (4K) at nominal frame rates (60fps), you could use the same technique to increase frame rate (240fps) at nominal resolutions (1080p).

Your challenge will be largely moving all that data. You will need to specify the cables and driving and receiving electronics for extremely high frequency operation. Consider:

$$1920 \times 1080 = 2073600 \text{ pixels}$$

If you want RGB color, with 8 bits per color, then:

$$2073600 \text{ pixels} \times 3 \text{ colors} \times 8 \text{ bits} = 49766400 \text{ bits per frame}$$

Then, 240 frames per second:

$$49766400 \times 240 = 11943936000 \text{ bits per second} \approx 12Gb/s$$

The HDMI 2.0 specification (according to Wikipedia) can transport up to 14.4Gb/s, so at 1080p resolution, your 240Hz could just fit. Interestingly, Wikipedia also says the maximum resolution supported is 3840×2160p60, which if you do the same math as above, works out to exactly the same data rate we just calculated.

I don't know in detail the HDMI or DVI specifications, but I'm not aware of any hard limit which would prevent you from signaling at a 240Hz frame rate. Certainly 120Hz devices are commonly available. I suspect your challenges will be in finding video sources and sinks that support that framerate, and finding HDMI interfaces and cables that support HDMI 2.0, simply because it is so new.