Hello Sivaraman Radhakrishnan,
The Standard Distribution of codecs is distributed along the BSP Release trough NXP.com where you must accept click-thru license agreement prior to download. However, you may need to obtain additional licensing or other rights (e.g. MPEG LA, Via). NXP does not charge a license fee or royalty.
NXP is legally unable to provide guidance on when, where and how to obtain licenses as these are done by 3rd parties with varying and (sometimes) changing terms.
I would suggest you contact the owner of the specific codec you wish to use (as even H.264 has some variants) for information regarding royalties.
My apologies for the inconvenience!
Regards,