The MdatBox field and related fields encapsulate media data for the requested fragment. The syntax of the MdatBox field is a strict subset of the syntax of the Media Data Container Box that is defined in [ISO/IEC-14496-12].
MdatBox (variable): The media data container.
MdatBoxLength (4 bytes): The length of the MdatBox field, in bytes, including the MdatBoxLength field. If the value of the MdatBoxLength field is %00.00.00.01, the MdatBoxLongLength field MUST be present.
MdatBoxLongLength (8 bytes): The length of the MdatBox field, in bytes, including the MdatBoxLongLength field.
SampleData (variable): A single sample of media. Sample boundaries in the MdatBox field are defined by the values of the DefaultSampleSize and SampleSize fields in the TrunBox field.
The syntax of the fields that are defined in this section, specified in ABNF [RFC5234], is as follows.
MdatBox = MdatBoxLength MdatBoxType [MdatBoxLongLength] MdatBoxFields MoofBoxType = %d109 %d100 %d97 %d116 MoofBoxLength = BoxLength MoofBoxLongLength = LongBoxLength MdatBoxFields = *( SampleData ) SampleData = *BYTE