Silverlight AV

Video

• Raw Video
• YV12 - YCrCb(4:2:0)
• RGBA - 32 bit Alpha Red, Green, Blue
• WMV1: Windows Media Video 7
• WMV2: Windows Media Video 8
• WMV3: Windows Media Video 9
•       Supports Simple and Main Profiles.
•       Supports only progressive (non-interlaced) content.
• WMVA: Windows Media Video Advanced Profile, non-VC-1
• WVC1: Windows Media Video Advanced Profile, VC-1
•       Supports Advanced Profile.
•       Supports only progressive (non-interlaced) content.
• H264 (ITU-T H.264 / ISO MPEG-4 AVC)
•       Supports H.264 and MP43 codecs.
•       Supports Base, Main, and High Profiles
•       Supports only progressive (non-interlaced) content.
•       Supports only 4:2:0 chroma subsampling profiles.

Audio

• “1”. This is Linear 8 or 16 bit Pulse Code Modulation. Roughly speaking, this is WAV format.
• "353" - Microsoft Windows Media Audio v7, v8 and v9.x Standard (WMA Standard)
• "354" - Microsoft Windows Media Audio v9.x and v10 Professional (WMA Professional)
• Supports full fidelity decoding of WMA 10 Professional Low Bit Rate (LBR) modes in the 32-96 kbps range.
• Multichannel (5.1 and 7.1 surround) audio content is automatically mixed down to stereo.
• 24 bit audio will return silence.
• Sampling Rates beyond 48000 return an invalid format error code in same-domain and a 4001 in cross-domain scenarios.
• "85" - ISO MPEG-1 Layer III (MP3)
• "255" - ISO Advanced Audio Coding (AAC)
• Supports Low Complexity (AAC-LC) decoding at full fidelity (up to 48 kHz).
• High Efficiency (HE-AAC) encoded content will decode only at half fidelity (up to 24 kHz).
• Multichannel (5.1 surround) audio content is not supported.

Unsupported Formats
The following formats are not supported:

• Interlaced video content
• Windows Media Screen
• Windows Media Audio Professional
• Windows Media Voice
• Combination of Windows Media Video and MP3 (WMV video + MP3 audio)
• Combination of WMV with AAC-LC

 关于Microsoft的若干Codec
Microsoft的AV文件后缀大多都是WMV，然后在大多数情况下，WMV文件是被封装在一个ASF 的container format中的。文件扩展名.wmv描述了一个使用WindowsMedia Video codec的文件。ASF container还可以包含数字版权管理。
WMV除了表示一种文件名后缀外，还表示一类codec，它也是在WMV 家族中公认的一种codec。这类codec的第一个版本是Windows Media Video 7(WMV 7)，4个字母的代号为WMV1，在1999年引入，是在Microsoft的MPEG-4 Part 2的实现的基础上作的。之后又出现了Windows Media Video (WMV 8，WMV2)，Windows Media Video 9(WMV 9，WMV3)。WMV9后来升级成为WVC1.
注意： 这里讲的都是codec，更WMP是没有关系的。
WMV家族中还有一类codec，称为Windows Media Video Screen (WMV Screen)，它用于捕捉屏幕内容，转换第三方屏幕抓取软件获取的Video为WMV Screen文件。它的一个应用就是computer step-by-step demonstration videos。
Windows Media Video Image (WMV Image) is a video slideshow codec。