Use Blur to apply and customize a blur filter to a clip.
To access the Blur menu, use:
Batch, then select a node from the Node bin.
Timeline, then use Batch FX (see Creating Batch FX).
Timeline, then add Timeline FX from the Effects ribbon (see Adding Timeline FX).
Tools, then select from the menu (See Accessing Tools).
The Modular Keyer, then select a node from the Node bin.
The Action Media list (see Adding Effects to Media).
This node accepts a front and a matte clip, and outputs a result and outmatte. The outmatte clip can have a different level of blur than the result clip.