ZLS: An Efficient Lossless Compression for Depth-Video Streaming

This paper introduces an efficient compression scheme—Z-lossless (ZLS)—for video applications with depth streams. ZLS utilizes a novel histogram compression module together with a customized predictor-corrector model and an entropy coder based on adaptive Golomb codes. It achieves a lossless compression of 9:1 for Kinect-like depth data with ultra-lightweight computations, which is ideal for streaming depth data in Metaverse video applications over narrow communication channels and low-bandwidth portable devices. To prove the efficiency and feasibility of ZLS, we present two practical, portable video applications using our implementation of ZLS on embedded platforms (i.e., a handheld Kinect camcorder and a Kinect-equipped hexa-copter). ZLS runs on a single ARM Cortex A9 core clocked at 1.7GHz at 42Hz, and outperforms its competitors (such as state-of-the-art lossless general purpose, image, video and depth stream compression) in terms of compression ratio and computation efficiency verified by extensive empirical results.