Refactor out transcode as a separate library (#597)
* refactoring transcode as library * refactored as lib * remove unused deps * fix imports * cleanup * modified README * run fmt * make clippy happy * clippy cd * use std * PR comments * fixit
* refactoring transcode as library * refactored as lib * remove unused deps * fix imports * cleanup * modified README * run fmt * make clippy happy * clippy cd * use std * PR comments * fixit