H.264 in SIP

H.264 in SIP can contain these optional parameters, which be included in the "a=fmtp" line of SDP if they appear: profile-level-id, max-mbps, max-fs, max-cpb, max-dpb, maxbr, redundant-pic-cap, sprop-parameter-sets, parameter-add, packetization-mode, spropinterleaving-depth, deint-buf-cap, sprop-deint-buf-req, sprop-init-buf-time, sprop-max-dondiff, and max-rcmd-nalu- size.

The profile-level-id parameter is a base 16[6] hexidecimal representation of the following three bytes in sequence:

1. profile_idc
2. profile_oip—Composed of the values from constraint_set0_flag, constraint_set1_flag, constraint_set2_flag, and reserved_zero_5bits—in order of bit significance, starting from the most significant bit.
3. level_idc—Note that reserved_zero_5bits is required to be equal to 0 in [1], but other values for it may be specified in the future by ITU-T or ISO/IEC.