WMV files use Microsoft’s Advanced Systems Format (ASF). Microsoft’s final specification is a PDF and was not opened; the layouts here come from the comment tables in the open-source getID3 library, and what could not be confirmed is marked.
Object header
| Offset | Size | Type | Name | Meaning |
|---|---|---|---|---|
| 0 | 16 | GUID | Object ID | The object’s type. |
| 16 | 8 | QWORD | Object Size | Size in bytes, including this header. |
| 24 | varies | Object data |
A GUID is written in text in the usual form, but on disk its first three groups are
little-endian. The Header Object 75B22630-668E-11CF-A6D9-00AA0062CE6C
is stored as 30 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C.
Top-level objects
| GUID | Object |
|---|---|
75B22630-668E-11CF-A6D9-00AA0062CE6C | Header |
75B22636-668E-11CF-A6D9-00AA0062CE6C | Data |
33000890-E5B1-11CF-89F4-00A0C90349CB | Simple Index |
D6E229D3-35DA-11D1-9034-00A0C90349BE | Index |
FEB103F8-12AD-4C64-840F-2A1D2F7AD48C | Media Object Index |
3CB73FD0-0C4A-4803-953D-EDF7B6228F0C | Timecode Index |
Objects inside the Header Object
| GUID | Object |
|---|---|
8CABDCA1-A947-11CF-8EE4-00C00C205365 | File Properties |
B7DC0791-A9B7-11CF-8EE6-00C00C205365 | Stream Properties |
5FBF03B5-A92E-11CF-8EE3-00C00C205365 | Header Extension |
86D15240-311D-11D0-A3A4-00A0C90348F6 | Codec List |
1EFB1A30-0B62-11D0-A39B-00A0C90348F6 | Script Command |
F487CD01-A951-11CF-8EE6-00C00C205365 | Marker |
D6E229DC-35DA-11D1-9034-00A0C90349BE | Bitrate Mutual Exclusion |
75B22635-668E-11CF-A6D9-00AA0062CE6C | Error Correction |
75B22633-668E-11CF-A6D9-00AA0062CE6C | Content Description |
D2D0A440-E307-11D2-97F0-00A0C95EA850 | Extended Content Description |
7BF875CE-468D-11D1-8D82-006097C9A2B2 | Stream Bitrate Properties |
2211B3FA-BD23-11D2-B4B7-00A0C955FC6E | Content Branding |
2211B3FB-BD23-11D2-B4B7-00A0C955FC6E | Content Encryption |
298AE614-2622-4C17-B935-DAE07EE9289C | Extended Content Encryption |
2211B3FC-BD23-11D2-B4B7-00A0C955FC6E | Digital Signature |
1806D474-CADF-4509-A4BA-9AABCB96AAE8 | Padding |
Objects inside the Header Extension
| GUID | Object |
|---|---|
14E6A5CB-C672-4332-8399-A96952065B5A | Extended Stream Properties |
A08649CF-4775-4670-8A16-6E35357566CD | Advanced Mutual Exclusion |
D1465A40-5A79-4338-B71B-E36B8FD6C249 | Group Mutual Exclusion |
D4FED15B-88D3-454F-81F0-ED5C45999E24 | Stream Prioritization |
A69609E6-517B-11D2-B6AF-00C04FD908E9 | Bandwidth Sharing |
7C4346A9-EFE0-4BFC-B229-393EDE415C85 | Language List |
C5F8CBEA-5BAF-4877-8467-AA8C44FA4CCA | Metadata |
44231C94-9498-49D1-A141-1D134E457054 | Metadata Library |
D6E229DF-35DA-11D1-9034-00A0C90349BE | Index Parameters |
F55E496D-9797-4B5D-8C8B-604DFE9BFB24 | Timecode Index Parameters |
26F18B5D-4584-47EC-9F5F-0E651F0452C9 | Compatibility |
D9AADE20-7C17-4F9C-BC28-8555DD98E2A2 | Index Placeholder |
Stream and error correction types
| GUID | Meaning |
|---|---|
F8699E40-5B4D-11CF-A8FD-00805F5C442B | Audio media |
BC19EFC0-5B4D-11CF-A8FD-00805F5C442B | Video media |
59DACFC0-59E6-11D0-A3AC-00A0C90348F6 | Command media |
B61BE100-5B4E-11CF-A8FD-00805F5C442B | JFIF media |
35907DE0-E415-11CF-A917-00805F5C442B | Degradable JPEG media |
91BD222C-F21C-497A-8B6D-5AA86BFC0185 | File transfer media |
3AFB65E2-47EF-40F2-AC2C-70A90D71D343 | Binary media |
20FB5700-5B55-11CF-A8FD-00805F5C442B | No error correction |
BFC3CD50-618F-11CF-8BB2-00AA00B4E220 | Audio spread |
D6E22A00-35DA-11D1-9034-00A0C90349BE | Mutual exclusion: language |
D6E22A01-35DA-11D1-9034-00A0C90349BE | Mutual exclusion: bitrate |
D6E22A02-35DA-11D1-9034-00A0C90349BE | Mutual exclusion: unknown |