3D/2D comb filter in the ADV7842 / ADV7802

Hi

Where can I read more about working 3D/2D comb filter?

If I understand correctly, the comb filter 3D/2D is used for Y/C separation - is it?

3D comb (requires external SDRAM) is used for relatively slow picture content - is it?

For SECAM mode, which comb filter modes are used?

3D/2D comb filter are the same in ADV7842 and ADV7802?

Regards,
Alexander