Elemental Cloud is doing it, what added value do you offer?
I worked in a company that had its own encoding platform, worked nicely and had very little issues, still moved to elemental when the time came.
The hint it, you can not work only with dash, you need to deliver to all platforms and each platform has its own DRM. Now, If you are not going to use any DRM, then anyone could steal your encoded files and what is worse, anyone could build what you are building.
What I am saying is, think on what problem are you solving and what is the added value. IF there is none, use what is outhere now.