QuickTime Streaming

Hint Track Information Atom (`'hnti'` )

Hint track information atoms ('hnti' ) are defined both for movie-level user data atoms and for track-level user data atoms. The 'hnti' atom in the hint track's user data atom contains hint information specific to this track.

The 'hnti' atom contains child atoms that hold the actual hint information. Currently, only SDP child atoms ('sdp ' ) are defined. Servers should ignore child atoms whose type they do not recognize.

An SDP child atom has a 32-bit size field, a four-character type ('sdp ' ), and a data field. Note that the fourth character of the atom type 'sdp ' is an ASCII blank (hex 20).

The data field of an SDP atom contains a string with the track-specific information required to build an SDP file, such as "m=audio 0 RTP/AVP 96". The string itself has no count byte or delimiter. It's length is calculated by subracting 8 from the atom size. A single string can contain multiple lines of SDP text, separated by a carriage-return and linefeed (0D 0A hex).

The SDP text must be inserted in the proper place in the SDP file in order to build an SDP file for a movie. The SDP text for each track is inserted after any common SDP text, including SDP text taken from the movie-level 'hnti' atoms. Refer to the RFC for Session Description Protocol for precise line-ordering rules.

Hint Track Information Atom ( 'hnti' )

Hint Track Information Atom (`'hnti'` )