EXCLUSIVE

Birdman is NOT letting Lil Wayne out of his recording contract, no matter how much he bitches.

Sources close to Birdman tell us ... he's deeply offended by Weezy's public rants ... claiming Birdman has tried to derail his career by refusing to release his new album. Weezy didn't mince words, tweeting, "I want off this label and nothing to do with these people."

Birdman is unmoved and vows to duke it out in court if necessary, because a contract is a contract.

As for the delay in dropping the album, we're told Birdman says there's lots of administrative work that goes into releasing a record, and Weezy is just a rapper, not a businessman, so what does he know?

Birdman still intends to release the album, but on his time, not Weezy's.