WMA: 包括 Header Object， Data Object， Other top-level objects 文件头对象: File ProPerties Object Stream Properties Object 1 ...... Stream Properties Object N ---------------------------------------------------------------------------------------------------------------------- 以为列一些比较重要的 Header Object 0. File Properties Object (mandatory , one only ) Field name Field type Size (bits) Object ID GUID 128 Object Size QWORD 64 Number of Header Objects DWORD 32 Reserved1 BYTE 8 Reserved2 BYTE 8 总共30 个字节， 头16 字节固为 "30 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C"，Reserv ed1 和Reserv ed2 为保留字， 解码时不考虑， 编码固定设置为 0x 01, 0x 02。 1. File Properties Obect (mandatory , one only ) Field name Field type Size (bits) Object ID GUID 128 Object Size QWORD 64 File ID GUID 128 File Size QWORD 64 Creation Date QWORD 64 Data Packets Count QWORD 64 Play Duration QWORD 64 Send Duration QWORD 64 Preroll QWORD 64 Flags DWORD 32 Broadcast Flag 1 (LSB) Seekable Flag 1 Reserved 30 Minimum Data Packet Size DWORD 32 Maximum Data Packet Size DWORD 32 Maximum Bitrate DWORD 32 求总的播放时间时要减去Preroll 的值，Minimum Data Packet Size 和Maximun Data Packet Size 是固定相等的。 2. Stream Properties Object (mandatory, one per stream) Field Name Field Type Size (bits) Object ID GUID 128 Object Size QWORD 64 Stream Type GUID 128 Error Correction Type GUID 128 Time Offset QWORD 64 Type-Specific Data Length DWORD 32 Error Correction Data Length DWORD 32 Flags WORD 16 Stream Number 7 (LSB) Reserved 8 Encrypted Content Flag 1 Reserved DWORD 32 Type-Specific Data BYTE varies Error Correction Data BYTE varies 当 Stream Type 为 ASF_Audio_Media,既GUID("F8699E40-5B4D-11CF-A8FD-00805F5C442B")时...
