GliGli’s TileMotion video codec

This project achieved its goal: to find a novel way to compress a video so that the decoder is computationally cheap and trivially simple to write.

So far, the encoder is mostly FreePascal code with some x64 SSE3 assembler (additional libraries and tools being mostly C/C++) and has a GUI to showcase it.

The reference decoder is written entirely in javascript and uses HTML5 Canvas to decode, proving that minimal code and computing power is necessary.

Upon bitstream format maturity I will probably write a DirectShow plugin or something akin.

Online demo here: https://gligli.github.io/tiler/demo/

The project is in Release candidate stage and located at: https://github.com/gligli/tiler (go to the ‘releases’ section for binary downloads).

Author: GliGli License: GNU GPL v3

Details:

It’s a video lossy compressor, compression ratio is not too far to other well known video codecs like MPEG-4/AVC/… (It needs more bitrate, but eg. at 7-8MBits/sec it can do 720p with a good picture). Decoding is absurdly cheap (depacking LZMA2, which is used for the bitstream, costs about the same as the decoding itself).

The video format is based on keyframes / frames / palettes / tilemaps and tiles. Frames works a bit like old video game consoles where a frame is a tilemap with tile indexes and attributes (H/V mirrors, palette index, …). Tiles are 8*8 blocks of indexes that map to a palette. Palettes are RGBA8888 colors for any tile.

Here’s the whole decoder in javascript for reference : https://github.com/gligli/tiler/blob/master/decoders/htmljs/gtm.player.js

As a drawback, the encoder needs a lot of CPU, encoding a short video can take many hours depending on resolution and settings.