L-SMASH Source: A kind of "successor" and fork from FFmpegSource2, but also including the L-SMASH splitter for ISO Media containers (MP4, QT MOV, etc.) in addition to libav.
Latest builds by the_weirdo since VFR maniac doesn't provide binaries regularly anymore.
This is a software-only decoder, but very fast (especially when multi-threaded) and reliable, has less issues with non-MKV containers (which was the biggest limitation of FFMS2).
And there is even one more alternative:
DSS2Mod, a modified "DirectShowSource2" (based on the one shipped with Haali Media Splitter) which can use LAV Filters natively instead of installed DirectShow filters. The
Google Code project documents this different download link for the latest version.