If anyone is interested, here is a quick and dirty mcpr reader. I accidentally included some buildpath import sources, but that's fine since you'll need them if you are importing the project into an ide.
All this does is take the packets in the file and turn it more or less into plain text to show the values. That could then be used to... well... do something with the values :-p
https://github.com/Moonlight63/ReplayMod-.mcpr-File-Reader-api-
Normally I would release something with code as messy and un-commented as this, but it was an experiment more that anything else. it works! sortof.