Here's an interesting cross-platform (runs on Windows and Linux) open source IDE that sits on top of the GNU ARM tools:

http://ryansturmer.github.io/cuttlebug/

>Encoding should be trivial to paralellize, you just cut up a movie to
>a sequence of n clips and encode them independently.

That works great for multiple CPUs, but would be a disaster for GPU architectures.

I think that the real benefit of GPUs for transcoding will be seen once people start making new as-yet unimagined encoding schemes that are designed to do data parallel tasks that wouldn't even be considered on a traditional CPU.