Uploading Podcast Audio to YouTube
YouTube unfortunately does not provide you with the ability to upload audio tracks individually, which is a pain if you do not work with video (such as a podcast). The way to get around this limitation is to create a video which includes the desired audio track and a fixed image (i.e. cover-art) which lasts the duration of the track. There are many ways of achieving such a result, from iMovie and Windows Movie Maker to the online service TunesToTube. With a little research however, I was able to come up with a even simpler solution that only requires the ever useful ffmpeg.
$ ffmpeg -loop 1 -r 2 -i image.jpg -i input.mp3 -vf scale=-1:380 -c:v libx264 -preset slow \
-tune stillimage -crf 18 -c:a copy -shortest -pix_fmt yuv420p -threads 0 output.mkv
-loop 1 # loop over image stream
-r 2 # frame rate
-i image.jpg # image input file
-i input.mp3 # audio input file
-vf scale=-1:380 # apply scale filter, resize to 380p
-c:v libx264 # encode video to H.264 using libx264 library
-preset slow # sets encoding preset for x264
-tune stillimage # x264 input preset
-crf 18 # constant rate factor
-c:a copy # copy over audio input
-shortest # finish when shortest input ends
-pix_fmt yuv420p # set pixel format
-threads 0 # optimal number of threads to encode
output.mkv # output file