Display Stream Compression - Can you tell the difference?

What is Display Stream Compression?

Display Stream Compression (DSC) is a compression algorithm developed by the Video Electronics Standards Association (VESA). DSC is used to compress display data in a "visually lossless" manner without a major latency penalty (the latency penalty is typically less than .01 milliseconds).

What does "visually lossless" mean?

A lossless compression algorithm is a compression algorithm that does not reduce quality at all. A "visually lossless" compression algorithm on the other hand does technically reduce quality, but not to an extent that the human eye can visually detect under normal conditions.

Specifically this is how VESA defines "visually lossless":

By being visually lossless, a typical observer of a display, under typical viewing conditions, would in most cases not notice any difference or degradation of images or video after compression, when compared with the uncompressed image or video.

How much bandwidth does DSC save?

VESA advertises DSC as suitable for 3:1 compression with 24 bit color and 3.75:1 compression with 30 bit color. That means potentially over a 73% reduction to required bandwidth!

However while the active data (ie. data used for carrying pixel data) can achieve those compression ratios, the timings overhead isn't as compressible.

Below is simple bandwidth calculator that assumes that only the active bandwidth can be compressed:

Display Stream Compression Quiz

Test your vision! Can you tell the difference between an image without compression and an image that was compressed using Display Stream Compression? Simply click each image that you think was compressed with DSC.

This quiz does contain several very high resolution images and may take a while to load on slower internet connections.

All test images used on this page are from https://imagecompression.info/ and were compressed at a 3:1 compression ratio using DSC 1.2a.