Transcription work management portal/system/platform for online workers, "work from home" platform that allows online agents to do transcription work -- 2

We need a platform/system/portal that will manage transcription jobs and online workers, (something similar to [login to view URL], [login to view URL]) with functions and processes as described in the attachments ( have also attached some sample screenshots from other similar platforms just to help in understanding). Basically, we want to be able to manipulate audio/video files by splitting them into defined sizes and also by joining them back into their original sizes, allowing an Agent to listen/watch and be able to slow, speed, jump back and forth....just to be able to transcribe a file including slowing down the playback to be able to listen to audio in "slow motion". Some clients will want confidentiality meaning we will require an Agent to transcribe on our system and not download the files and upload the transcribed files as would be the case for nonsensitive projects. We want to manage time, quality, accuracy and money for each task/project meaning we would like to put in place measures that allow us to know if good work has been done and by who so that we always have the best Agents working for us, and if something goes wrong the Agents should be able to be notified