hear someone ~ing

[Darlene]

Hello, there!
I'd like to know if there's any difference in meaning or usage between the
following sentences.
1. i heard she complained about the heat.
2. i heard her complain about the heat.
3. i heard her complaining about the heat.
Thanks in advance!!

[Mister Micawber]

(1) is hearsay-- you did not hear her, someone else did.
(2) and (3) carry essentially the same meaning, but the continuous form emphasizes the immediacy of the situation for the narrative. (You heard her in these cases, of course.)