http://vdmx.vidvox.net/blog/hap
I did a quick test with 2 clips on 2 layers encoded to Hap and Hap alpha in VDMX and PhotoJPG and PNG(with alpha) in Modul8. Difference is 43%CPU (VDMX) versus 147%CPU(M8). Amazing!
BTW the same Hap encoded clips play in M8 at 85%CPU.