Would like to set up a basic decoder for M extension. Refer to [planning doc](https://docs.google.com/document/d/1CQu_JJjPz5PRu1B-brvyxw2hyEvEOPxiWGP4TfWSsaY/edit?usp=sharing) for suggested implementation plan.
Would like to set up a basic decoder for M extension. Refer to planning doc for suggested implementation plan.