LeBron's Mother -- The Valet SLAP FOOTAGE

TMZ has obtained security footage showing LeBron James' mother slapping a parking valet at a hotel in Miami Beach last week ... but the video shows Gloria James may NOT have made the first move.

During the encounter ... Gloria walks up to the valet, Rockfeller Sorel, and gets in his face over the parking situation. As Gloria verbally unloads, Rockfeller takes an advancing step towards Gloria and bumps her.

Gloria quickly recovers and unleashes the slap heard 'round the world with her left hand -- and then swings her purse at the guy's head with her right hand.

Sorel, clearly upset, takes several aggressive steps towards Gloria ... who then slips and falls while retreating.

Gloria gets off the ground and tries to go after the valet -- but several bystanders get in between the two and break it up.

Gloria was eventually arrested for battery and public intoxication -- and then, according to police, she started talking trash to one of the officers.

We called Gloria's Miami attorneys Christopher Lyons and Sandy Becher -- they declined to comment on the video or the matter at this time.

Meanwhile, the valet has made it very clear he intends to go after Gloria in court.