Original project, hosted here (https://code.google.com/p/gmf) looks abandoned. This is a patched version that compiles against Go 1.0.3 and ffmpeg-0.8.
This is "AS IS" version, i was able to compile it, but there is a lot of questions and TODOs.
The installation is pretty straightforward. Just define the ffmpeg include path.
export CGO_LDFLAGS="-L$FFMPEG_ROOT/lib/ -lavcodec -lavformat -lavutil -lswscale"
export CGO_CFLAGS="-I$FFMPEG_ROOT/include"
go get github.com/3d0c/gmf