Canon Vixia HF-R300 Manual page 21

Format and Bitrate for Recording
We want the cameras to record in the highest quality
*
possible. That is AVCHD (Audio Video Codec for High
Definition) with a bitrate of 24Mbps (twenty four
megabits per second). The letter code for 24Mbps on
the camera is MXP – think of it as "MaXimum Picture
quality".