Processing times will vary depending on many factors such as input file size, type, and location. Today, all of our processing happens in the western US region and we will be expanding to other regions soon. Generally, for HD and below, the processing is close to real-time or faster. For example, a 5 minute HD video will take around 4-5 minutes to transcode to MP4. For more complex content or high resolution/frame rate, or complex inputs, the processing time can vary. You are only billed for the duration of the output content with the Transcode API, not the processing time.