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How 8k UHD Displays for Emerging Technologies are Enabled in MIPI DSI

High resolution 8k UHD displays for emerging technologies like connected cars, IoT, and AR/VR (Augmented/Virtual Reality) require high bandwidth to support the high-resolution transmission. MIPI DSI is the widely used display interface, but the bandwidth provided by PHY layers isn’t sufficient enough to support the high-resolution displays; therefore, a compression technique like DSC (Display Stream Compression) is required. One of our recent blog discussed about DSC 1.2 in HDMI 2.1 – High Resolution Displays for Mobile, TV, PC and Automotive Enabled by DSC 1.2 in HDMI 2.1. In this blog, we will see how DSC 1.2 enables MIPI DSI to support the high-resolution displays for emerging applications.

The gap between growth of resolution and PHY bandwidth

If we analyze the gap between display resolution and PHY bandwidth over the past few years, we realize that display resolution is increasing rapidly; however, the bandwidth of PHY layers has not observed as much growth. The gap is depicted in the chart below:

To bridge this gap, users can either increase the number of parallel PHYs or use an efficient compression technique, such as DSC, to keep up with the demand of information in high display resolutions without increasing circuit complexity.

What does DSC v1.2 offer?

The DSC v1.2, developed by Video Electronics Standard Association (VESA), provides a wide variety of features to scale down the required bandwidth by 2 to 3 times.

  • Indexed Color History (ICH)In digital images, there are identical pixel values repeated in close proximity, and it is better to use the already coded values rather than coding them again. A number of recently-used pixel values are tracked in the ICH for this purpose. The encoder and decoder refer to this ICH to save space while compression and decompression are occurring.
  • Native Color Modes: This feature eliminates the need to convert pixels into different red, green, blue (RGB) components, which catalyzes the process of direct compression of incoming pixels with practically no quality loss. This increases the efficiency of compression even more than the usual chroma sub-sampling used in digital TVs, etc.
  • Higher bits per component: DSC v1.2 supports 14 bits and 16 bits per color component, enabling wide color depth compatibilities within the pixel formats, compared to a maximum of 12 bits per component offered previously.

Wide Range of Applications:

  • DSC is also enabling following emerging applications:
    • USB Type-C Dual Extended Monitors
    • AR and VR video capture
    • 10k resolutions mobile and TV displays
    • Automotive video cameras and serial interfaces

Some of the high resolutions are impossible to be implemented without 2x to 3x compression capabilities of DSC v1.2. DSC also considerably reduces the cost, area, and power simultaneously, and has become a mandatory industry norm nowadays.

Synopsys VIP for MIPI DSI

Synopsys VIP for MIPI DSI supports the latest VESA DSC v1.2 compression scheme. The VESA DSC 1.2 module is fully integrated in VIP for MIPI DSI, providing a complete solution for verification of high-resolution displays using compressed video across a wide spectrum of applications. Watch this space for further developments in the world of display and other protocols.

To understand DSC algorithm in more detail, refer our white paper – Analyzing the Losses in Visually Lossless Compression Algorithms.

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