wmv9才是VC-1的标准编码，从wmv1到wmv9,支持的视频分辨率上限越高,支持的清晰度上限也越大,而且相同清晰度下占用空间越小。
wmv1、2、3是跟早期mpeg4同级别的，wmv9（VC-1）是和H.264同级别的。
沒有wmv 9 ==>這個是widows media player by KKKK??????
只有wmv3 and vc1 是profile 不同
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Q: What is VC-1? What is WMV9? What’s the difference?
A: VC-1 is a codec specification as standardized by SMPTE in 421M.
WMV9 is an implementation of that specification.
Think of it this way: WMV9 is to VC-1 what x264 is to MPEG-4 AVC or DivX is to MPEG-4 ASP.
In the context of Microsoft video codecs, WMV9 and VC-1 can be considered one and the same.
A fine line can be drawn by saying that WMV9 is VC-1 video in the context of Windows Media:
inside an ASF container, or with WMA audio, or with WM DRM, or streaming from WM Servers, etc.
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An update. I've found some documentation. We support:
VC-1 (aka WMV9 Advanced Profile) with fourcc WVC1
WMV9 (aka WMV9 Simple and Main Profiles) with fourcc WMV3
WMV7 (fourcc WMV1) and WMV8 (fourcc WMV2) are not supported by the video decoder.
VC1 payload data does not include start codes.
WMV9 payload data does include start codes, and therefore payload data requires emulation prevention.
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