That's exactly what Stupeflix Tasks will do in a few weeks, along with video thumbnails strips, thumbnailing of videos at any point in time, video uploads, audio waveform, text to speech, video reverse etc. The beta doc is at https://stupeflix-tasks-api.readthedocs.org/en/latest/versio... , feel free to give me some feedback on it ! And if you want to do way more than just transcode, but create completely your video from images / music / videos , you can use the video rendering service at http://developer.stupeflix.com/ . It will migrated to the Tasks api too.

(Disclaimer : I am the CTO )