With latest AIR SDK 126.96.36.199 beta with Windows devices simple Video and StageVideo for me works fine but we still have some problems:
1) If you disable hardware decoder:
NetStream::useHardwareDecoder = false
H.264 videos doesn't shows.
2) H.264 videos doesn't shows with Stage3D VideoTexture
3) H.264 videos with resolution more than 4096 pixels by any side doesn't shows.