BT.656usestheBT.601-definedverticalblankingintervals.
However,notethatactiveresolutions otherthan720x486
and720x576maybesupported(effectively cropping the image)
byadjustingwhere the EAV and SAV codes and vertical blanking
intervals occur.
可能720*486只是BT.656协议的一个TYPICAL值吧我觉得,也可以可以变成NTSC标准的
720*480。