How do I use AEIO_OutputFrame?

Hi,

I am trying to write a new export plugin based on the FBIO sample for CS6.

I am struggling to understand how to use the AEIO_Outputframe. I get the call and can see that this has already opened the frame file that I want to fill but can't see how to get access to the file. I understand that the PF_EffectsWorld contains the AE pixel data that I need to manipulate to put in the file but can not see any documented reference for how to use this call and what an AEIO_OutSpecH is and how I might use that either.

I would really appreciate your help.

Thanks,

Richard