H264 two alignment methods

H264 has two alignment methods:
1. AVC (length-prefixed)
2. Annex B (0x000001 start code prefix)

ISO/IEC 14496-10:
http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=56538
ITU-T H.264:
http://www.itu.int/rec/T -REC-H.264