V4L2_STD_A2_B
#define V4L2_STD_A2 (V4L2_STD_A2_A | V4L2_STD_A2_B)
#define V4L2_STD_PAL_BG_A2_B (V4L2_STD_PAL_BG | V4L2_STD_A2_B)
return V4L2_STD_A2_B;
params->std |= V4L2_STD_A2_B;