What Is Display Stream Compression And Why Is It Important?

DisplayPort cable and HDMI cable on a keyboard
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Some displays rely on a technology called Display Stream Compression (DSC) to display large resolutions at high frame rates. While the feature is often associated with the DisplayPort standard, HDMI devices can also take advantage of it.

So what is DSC and how is it different from other types of compression?

Compression of playback streams is lossless

compression is the act of squeezing data together so that it takes up less space. In the case of DSC, this compression is necessary because display standards such as DisplayPort 1.4 and HDMI 2.1 are limited to 32.4 Gbps and 48 Gbps, respectively.

Unlike lossy compression used in JPEG images or MP3 audio files, DSC is visually lossless, meaning you won’t notice it while in use. By using DSC, you can achieve higher resolutions and faster refresh rates on supported screens, and some monitors require this for peak performance.

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Another use of DSC is to run multiple monitors with high resolutions and frame rates through hubs.

Using DSC with DisplayPort and HDMI

DSC is used in both the DisplayPort 1.4 and HDMI 2.1 standards. DisplayPort 1.4 only supports 4K resolution in HDR at 60Hz in full 10-bit color natively, but with DSC this is increased to 4K 120Hz (HDR) or 8K at 60Hz.

HDMI 2.1 goes even further, with support for 8K 60 Hz in full 12-bit color native (or 4K HDR at 120 Hz in full 12-bit). Add DSC to the mix to enable up to 10K 120Hz in 12-bit color, for which almost three times (120.29 Gbps) the bandwidth that HDMI 2.1 provides (48 Gbps).

Close-up of DisplayPort and HDMI connections
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DSC is something that “should just work”, provided you have the right hardware for the job. Use with DisplayPort requires a DisplayPort 1.4 cable, a source device, and a compatible monitor, while HDMI connections require a HDMI 2.1 compatible cable, and support on both source and screen.

The first HDMI 2.1 source devices hit the market in 2020 with the arrival of the Xbox Series X, PlayStation 5, and NVIDIA’s 30-series graphics cards. DisplayPort 2.0 is further improved from 1.4, taking the maximum bandwidth from 32.4 Gbps to 77.37 Gbps, more than doubling the bandwidth and native, uncompressed 4K HDR at 120Hz support.

Comes to a USB port near you

The USB 4.0 standard supports DisplayPort Alt Mode 2.0 to enable up to 16K resolutions on a single screen thanks to DSC. DisplayPort 1.4 can already be used over USB-C to enable up to 8K at 60Hz, but 2.0 devices will see a huge boost in bandwidth capacity.

Learn more about how USB 4.0 will further enhance the USB-C connector as the new standard connection for charging, data transfer and even controlling a display.

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