Zeranoe builds of FFmpeg 2.2.1 are now available.
There has been recent x265 issues that caused the builds to not work on Windows XP.
To compile version 2.2 builds of FFmpeg either x265 would need to be dropped, or support for Windows XP would need to be dropped.
I believe it is best to avoid confusion by offering 12 different builds of FFmpeg to support all possible situations, and wait until a new release version is available that supports the newer API in x265.
Zeranoe builds of FFmpeg 2.1.4 are now available.
This is a new release of the MingGW-w64 Build Script
Zeranoe builds of FFmpeg 2.1.3 are now available.