GL_APPLE_ycbcr_422
http://oss.sgi.com/projects/ogl-sample/registry/APPLE/ycbcr_422.txt
	GL_YCBCR_422_APPLE 0x85B9
	GL_UNSIGNED_SHORT_8_8_APPLE 0x85BA
	GL_UNSIGNED_SHORT_8_8_REV_APPLE 0x85BB