Open source Panda3D uses a commercial sound library called FMOD to play sound. If your program is not intended to make any money, and is not charged for in any way, then you may use FMOD in it for free.

FMOD is a very capable multi-platform sound engine. FMOD supports various types of sound files - MP3, WAV, AIFF, MIDI, MOD, WMA, OGG Vorbis. More detailed descriptions of FMOD, and the FMOD licenses are available at their website http://www.fmod.org.

If you do not wish to use FMOD in your progam, remove the fmod.dll and libfmod_audio.dll files from the panda \bin folder. Note that if you do remove FMOD, Panda3D will not be able to play or manipulate sounds.

Also note that even without Panda3D's built-in sound support, Python can still be used play sounds through other libraries, such as Pygame, or PyOpenAL. Note that the current version of Panda 3D also supports the OpenAL library.