Bino (also called Bino3D) is a free video player that supports stereoscopic 3D video, with a wide variety of input (L/R in separate streams, in side by side, top and bottom or alternate lines). Output formats can be for Anaglyph glasses from colour to Dubois method, to produce anaglyph images, L/R in side by side, or top and bottom, or in alternating rows or columns. Beside the powerful 3D viewer, Bino is also an excellent software tool for multi-display video, e.g. for seamless video walls, Virtual Reality installations or other multi-projector setups. Furthermore, Bino supports scripting, high precision colour in and output, and simultaneous dual camera input.
Available for Linux, Mac OS X, and Windows on https://bino3d.org. (free)
A (paid) alternative viewer (at least for 3D videos) can be found on http://www.3dtv.at/