WMA文件格式和解码流程

1 文件格式(ASF)

ASF:Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming media. ASF is part of the Windows Media framework.—from google define

Header Object	Required
Data Object	Required
Index Object	Optional

Object format

Object GUID	16 Bytes
Object Size	8 Bytes(the value is 24 + Object Data Size)
Object Data	(Object Size – 24)Bytes

1.1 Header Object(objects can apper in any order)

File Properties(Required)

Header Extention(Required)

Stream Properties(At least one stream properties object)

……

Stream Properties

Other header Object(optional)

1.2 Data Object

Data Packet 0

Data Packet 1

……

Data Packet N

Data Packet’s length is fixed. Data Packets are devided based on the time.

1.3 Index Object(skiped)

2 解码原理及流程

3 附录

http://ffmpeg.org/