视频流格式
ACL_JPEG_CSS_444 = 0
ACL_JPEG_CSS_422 = 1
ACL_JPEG_CSS_420 = 2
ACL_JPEG_CSS_GRAY = 3
ACL_JPEG_CSS_440 = 4
ACL_JPEG_CSS_411 = 5
ACL_JPEG_CSS_UNKNOWN = 1000