Dennis Quaid -- 'Meltdown' Video Smelling Like a Stunt (VIDEO)

Something is rotten in Hollywood, and it's that alleged Dennis Quaid "meltdown" video -- because we got him in New York City in full promotional mode ... and more and more this thing's looking like a stunt.

Quaid was out Tuesday afternoon after leaving a media event for his new scripted drama on Crackle.

The timing of the announcement seems convenient ... coming the day after the video of Dennis ranting -- allegedly on a movie (or TV) set -- goes viral.

Our photog asked Quaid to tell us the truth about the vid -- and while he said very little ... check out the smile.

For the record, a Crackle spokesperson says they had nothing to do with the viral clip.

Watch our vid of Dennis, then watch the rant again and then tell us ...