MetalHuffman
A GPU huffman decoder for iOS on top of Metal, adapted from Basic Texturing example provided by Apple. This decoder is known to work on iOS and should work on other Metal capable hardware.
Overview
This project implements a huffman decoder directly on top of Apple's Metal API. Inspired by [huff0] https://github.com/Cyan4973/FiniteStateEntropy
Decoding Speed
This code is needed for 1 reason only, speed! Decoding bytes of grayscale image data to be precise. While huff0 is an impressive approach, it is not as fast as lz4. Even lz4 is not fast enough to decode video at full screen iOS sizes of 2048x1536 at 30 FPS. The decoding needs to be done directly on the GPU so this code was created.
Implementation
See AAPLRenderer.m and AAPLShaders.metal for the core GPU rendering logic. A table based huffman encoder and decoder are also included.