Since we are all plugging our competing projects, here's mine: <a href="https://github.com/alexstaubo/tootsie" rel="nofollow">https://github.com/alexstaubo/tootsie</a><p>* Written in Ruby with Sinatra.<p>* Supports both SQS and AMQP (eg., RabbitMQ).<p>* Simple REST interface for submitting jobs.<p>* Can get/put both HTTP and S3 URLs.<p>* Image support: Scaling, cropping, format conversion, EXIF/IPTC stripping. Uses ImageMagick.<p>* Audio/video support: Scaling, format conversion, thumbnail extraction from videos. Uses ffmpeg.<p>* Has a helper component that provides live upload progress, jQuery uploader, etc.: <a href="https://github.com/bengler/tiramisu" rel="nofollow">https://github.com/bengler/tiramisu</a><p>Tootsie is intended as a generic conversion/transcoding framework, so it does more than just thumbnail images.<p>Oh, and it has been run in production for a long time.