A Detailed Explanation of DSC Technology and Its Application in HDMI and DP

What is DSC?

Display Stream Compression (DSC) is a lossless compression standard defined by VESA (Video Electronics Standards Association) to reduce the data transmission required for display signals. The goal of DSC is to compress data to about one-third of its original size with minimal loss in visual quality, thereby improving bandwidth utilization efficiency. DSC allows display devices to support higher resolutions, faster refresh rates, and richer color depths without significantly increasing data bandwidth. This makes DSC an incredibly effective technology for ultra-high-definition displays, especially for 8K, 4K, and other high-resolution screens.

DSC uses prediction-based encoding for data compression. Specifically, it employs block-based Delta-Pulse-Code Modulation (Delta PCM) and limited color conversion techniques to achieve compression. This reduces the bandwidth requirement while ensuring that the image quality loss is imperceptible to the human eye. As a result, DSC has become very popular in TVs, monitors, and mobile display devices.

Comparing HDMI and DP Standards

HDMI and DP are the two most widely used display interface standards today. Both support high-resolution displays, but they differ in the bandwidth and features supported by their respective versions. Below, we provide a detailed comparison of the bandwidth and the supported resolutions and color modes with and without DSC enabled for various versions of HDMI and DP.

Applications of DSC in HDMI and DP

The primary application of DSC in HDMI and DP is to address the bandwidth limitations at high resolutions and refresh rates. Without DSC, transmitting an 8K video signal may require very high bandwidth, which places high demands on the quality and length of the interface cables. DSC compression effectively reduces the bandwidth demand, thereby minimizing the pressure on the interface and enabling smooth ultra-high-definition display experiences.

For example, with HDMI 2.1, enabling DSC allows 8K @ 120Hz resolution to be transmitted within the limited bandwidth. For DP 2.0, enabling DSC allows it to support up to 16K resolution, which is particularly important for future large display devices or AR/VR devices.

Advantages and Challenges of DSC Technology

The biggest advantage of DSC is its ability to support ultra-high resolutions and refresh rates under limited bandwidth, which is crucial for modern display devices. Furthermore, its compression algorithm is optimized to maintain high image quality visually, with almost no noticeable loss in picture quality.

However, DSC does come with some challenges, such as potential color distortion introduced during compression and minor artifacts in images with complex patterns under certain extreme conditions. However, these imperfections have minimal impact on human perception, especially in fast-moving scenes where they are hard to notice.

Summary

DSC technology has brought significant bandwidth optimization to interfaces like HDMI and DP, enabling high-resolution, high-refresh-rate, and high-color-depth displays without exceeding the physical bandwidth limits of existing interfaces. With support for DSC in HDMI 2.1 and DP 2.0, new possibilities for 8K and even 16K displays are opening up, which is crucial for the development of future display technologies.

In conclusion, DSC is an effective solution for bridging the gap between high-resolution and high-bandwidth requirements, allowing us to experience better visual effects on current hardware. As display technology continues to advance, DSC and similar compression technologies may become standard features for high-resolution displays.