TriDef actually converts traditional 2D media into 3D by figuring out the 3d geometries that may be present in a 2.5D image and translating them into some form of stereoscopic encoding (color bands, blanking, or any number of methods depending on what the hardware supports).
At this time I am not aware that any stereoscopic 3d hardware is supported at all on GNU/Linux. This technology is heavily patented, and there is very little consumer demand on the Linux platform for the functionality, so I think it will very likely be many years (if ever) until we see any driver support for this -- particularly in the open source drivers.
Also, the future is stereoscopic 3d protocol used by HDMI 1.4, which your card is too old to support.... I think if this support ever did come (e.g. with OpenGL 4.2), your best bet would be to get a Radeon HD6000 series or later, which supports HDMI 1.4, and a monitor supporting HDMI 1.4 stereoscopic 3d protocol.