It's recommended for loops and samples. There is a trade-off that you get with Hap videos - you get a lot less CPU use, but the files take significantly more space than MP4 files. For this reason, I wouldn't suggest that you convert longer videos, such as music videos, to this format. It's great for the Sample Player though, or for shorter video loops. As for which codec to use. Use Hap Alpha if you have a file that you want to include an Alpha channel (transparency) with. The Hap codec should be fine for most loops, but if you see a noticeable lowering in quality on particular videos, then use Hap Q (which has a higher quality, but also larger file size).
