Quote:
Originally Posted by 1080PsF
Of coarse the author of this article is passing on incorrect information. He is saying that a 720p signal is half of the bandwidth of a 1080i signal but that is wrong because the 720 signal is 60 frames per second where as the 1080 signal is only 30Fps. 720 is half the pixels but double the frames making the bandwidth the same.
|
Not true.
Neglecting differences in compression efficiencies between interlaced and progressive scan (progressive scan compresses more easily), 720p/60 uses approximately 11.8 perecent less bandwidth than 1080i. A 720p frame only contains approx. 4/9 the number of pixels in a 1080i/p frame.
Also, 720p does not have to broadcast at 60 frames per second. Under the ATSC spec, it can be broadcast at 30 frames per second or even 24 frames per second, but I have yet to see any broadcaster using the two lower frame rates.