STM_CTRL_IMAGE_FORMAT
desc->stm_ctrl &= ~STM_CTRL_IMAGE_FORMAT(0xF); /* clear image format */
desc->stm_ctrl |= STM_CTRL_IMAGE_FORMAT(img_fmt);
cfg_desc->stm_ctrl = STM_CTRL_IMAGE_FORMAT(MXC_JPEG_YUV422);
STM_CTRL_IMAGE_FORMAT(img_fmt);
if (img_fmt == STM_CTRL_IMAGE_FORMAT(MXC_JPEG_YUV420)) {