UVC_BUF_STATE_ACTIVE
if (buf->state != UVC_BUF_STATE_ACTIVE) {
buf->state = UVC_BUF_STATE_ACTIVE;
if (buf->state != UVC_BUF_STATE_ACTIVE) {
buf->state = UVC_BUF_STATE_ACTIVE;
meta_buf->state = UVC_BUF_STATE_ACTIVE;
if (length <= 2 || !meta_buf || meta_buf->state != UVC_BUF_STATE_ACTIVE)