These are general guidelines on viewer-features needed to use all jFish features.
Using the RestrainedLove API will let the HUD do certain things like rotate your avatar, enhanced drunkess effects etc. The official viewers don't come with RLV installed. A lot of third party viewers have it built in though, you will have to refer to these viewers to see if they support RLV and how to enable it.
In phoenix/firestorm: Hit CTRL+ALT+D to enabled the Advanced menu (up top). Click advanced > Enable RestrainedLove API. You will need to restart your viewer.
Media On A Prim
This feature I believe only exists in viewer 2 & 3 based viewers, like the official ones and firestorm. This is used for in-world storefronts, as well as for the jfish radio system. You will probably need to go into properties (ctrl+p) > audio & video, and config the media settings there. This will differ from viewer to viewer.
Note: We could use some guides here on how to set this up properly in various viewers, we would appreciate it if someone wrote a guide here.