There are a handful of plug-ins out there that expand what codecs DirectShow can recognize.
The folks at Renderheads released a version of the Hap-codec for DirectShow sometime ago that will allow you to play back Hap-encoded files in .avi contains.
http://www.renderheads.com/downloads/2015/HapDirectShowCodecSetup.exe
I also just shared ofxDSVideoPlayer which natively plays back Hap files on the graphics card (the Renderheads version would copy to pixels first). If you're on windows this will be faster than using the Hap addon that uses QuickTime.
https://github.com/secondstory/ofxDSHapVideoPlayer
Jeremy