the frames are doubled (from a 25 frame source) on broadcast (to avoid flicker) for display devices that lack any kind of frame doubling ability. widescreen 16:9 material has only the width scaled down to fit 720 pixels instead of an unscaled 1024 width. smpte 344m defines a 576p50 standard with twice the data rate of bt.601, using 704 × 576 active pixels with 16 x 576 horizontal blanking pixels.