Multithreaded transcoding

[markuspeloquin]

Due to some stupid Winamp bugs, I have to re-transcode and transfer my entire library to my ipod. The estimate on time remaining is 6.5 hours because it's using the simple approach of one track at a time. I would love it if you could use all my CPUs. I'll even give you the algorithm (in Perlish pseudocode)!

@no_transcode = grep { !need_transcode($_) } @tracks_to_transfer;
@transcode = grep { need_transcode($_) } @tracks_to_transfer;
transfer($_) for @no_transcode;
# Start NCPUS threads that all repeatedly pull a track off the shared queue and send it to transfer()
async_workers(NCPUS, shared_queue(@transcode), transfer);

That's how I'd do it with threads anyway.

edit one more note: course-grained parallelism is SO EASY please do it