* @pads: the collectpads to use
* @cdata: collect data of corresponding pad
* @buf: buffer being clipped
-* @outbuf: output buffer with running time, or NULL if clipped
+* @outbuf: (allow-none): output buffer with running time, or NULL if clipped
* @user_data: user data (unused)
*
* Convenience clipping function that converts incoming buffer's timestamp