2.2.4.3 TrafBox

The TrafBox and related fields encapsulate metadata specific to the Requested fragment and track. The syntax of the TrafBox field is a strict subset of the syntax of the Track Fragment Box defined in [ISO/IEC-14496-12].

TrafBox (variable): Top-level metadata container for track-specific metadata for the fragment. The following fields are required and MUST be present in TrafBoxChildren: TfhdBox, TrunBox.

TrafBoxLength (4 bytes): The length of the TrafBox field, in bytes, including the TrafBoxLength field. If the value of the TrafBoxLength field is %00.00.00.01, the TrafBoxLongLength field MUST be present.

TrafBoxLongLength (8 bytes): The length of the TrafBox field, in bytes, including the TrafBoxLongLength field.

The syntax of the fields defined in this section, specified in ABNF [RFC5234], is as follows:

TrafBox = TrafBoxLength TrafBoxType [TrafBoxLongLength]                                                           
          TrafBoxChildren                                                          
TrafBoxType = "t" "r" "a" "f"                                                          
TrafBoxLength = BoxLength                                                          
TrafBoxLongLength = LongBoxLength                                                          
TrafBoxChildren = 2 *( TfhdBox / TrunBox                                                           
                       / VendorExtensionUUIDBox )