The ceremony in front a crowd of around a thousand people including heads of civic and religious groups follows a call by the rebels two weeks ago for people to hand in any pornographic material they owned.
A Tiger official Chilliyan told the crowd it was the duty of every Tamil to get rid of such obscene films in order to protect their culture.
The rebel movement has in the past accused the Sri Lankan authorities of distributing obscene material in an attempt to subvert Tamil culture.
From the newsroom of the BBC World Service