The ffvp8 library is this new VP8 decoder created by three FFmpeg developers and after a few weeks of work it's already complete enough to be bit-exact with that of Google's libvpx, while it's much faster than the official decoder.
In this blog post detailing the work, benchmarks are shared from two different video clips across five different system configurations. With all ten test cases, ffvp8 was the clear winner over libvpx. The FFmpeg decoder also had a particularly strong advantage when running on 64-bit hardware/software. While these numbers are already great for FFmpeg, the developers still have other optimizations planned.
The FFmpeg ffvp8 decoder should be in use by various multimedia applications as soon as they pull in the newest FFmpeg code.