The video player first needs to download the entire video before it can start playing, thus appearing to be a bit slow at first, so have patience. You can start the video by clicking on each player. The top left player runs on the main thread, the remaining players run in background worker threads.
Building the demo:
Install and configure Emscripten (https://github.com/kripken/emscripten)
The code for the demo is in the Decoder folder, to build it run the make.py python script.
The decoder expects an .mp4 file and does not support weighted prediction for P-frames and CABAC entropy encoding. To create such bitstreams use ffmpeg and x264 with the following command line options:
ffmpeg -y -i sourceFile -r 30000/1001 -b:a 2M -bt 4M -vcodec libx264 -pass 1 -coder 0 -bf 0 -flags -loop -wpredp 0 -an targetFile.mp4