Cody Garbrandt: I'll Release T.J. Dillashaw KO Video, Unless ...

Cody Garbrandt says he's ready to release video footage showing him knocking out T.J. Dillashaw during a training session ... unless his UFC rival does one very humiliating thing.

Cody is out in Vegas for UFC 209 where he confirmed the video is very real -- claiming it was shot sometime around 2012.

The reigning bantamweight champ says he's sick and tired of T.J. claiming the KO never happened and he's wants to release the footage to protect his credibility.