It is open source, however i have no idea where the source is, HatCat seems to be doing most the work over at the Project64 forums
http://forum.pj64-emu.com/showthread.php?t=4422 It's a modified Angrylion RDP
RPGMaster is also doing a lot of work, i'm sure if you asked one of them they'd happily get you on board. For HLE video you can use RiceVideo or hell Jabo3D which is in the Project64 source. I'd love you forever if you can fix up this emulator
Source of Project64:
http://www.pj64-emu.com:8090/project64.development/
If you coordinate with RPGMaster you may want to jump to 1964, he's been trying to spruce that up
http://forum.pj64-emu.com/showthread.php?t=4422 It's a modified Angrylion RDP
RPGMaster is also doing a lot of work, i'm sure if you asked one of them they'd happily get you on board. For HLE video you can use RiceVideo or hell Jabo3D which is in the Project64 source. I'd love you forever if you can fix up this emulator

Source of Project64:
http://www.pj64-emu.com:8090/project64.development/
If you coordinate with RPGMaster you may want to jump to 1964, he's been trying to spruce that up
