For the Transcode API, billing is charged per minute of each output file that the API generates. If you concatenate 2 10-minute video files into a single output file, billing is based upon the summed duration of the files (20 output minutes). Pricing is based upon which codec, resolution and frame-rate is used. If you shorten a 10 minute file to a 1 minute output, you are only billed for that output. HLS and DASH packaging and image outputs are not charged additionally but require you to generate audio or video outputs in the same request. See our Pricing page for output pricing details as well as some example usage.