What is the information content of an HDTV picture?

Question

1100 by 1100 pixels.

What is the information content that must be transmitted each second in an HDTV broadcast?

Answer 1

Currently - there is 8 bits per pixel for the color so this would be 8 x 1100 x 1100 for a single screen full.

I believe the screen is refreshed at 60 times per second so this gives us:

8 x 1100 x 1100 x 60 = number of bits per second.

But I dont think 1100 x 1100 is one of the defined standards. I know 1080 vertical resolution and the horizontal pixel count escapes me.

But this would give us 8 x 1080 x <horizontal pixel count> x 60

Answer 2

HDTV broadcasts are

1.) 1080i

1920x1080 pixels at 60 fields per second (an even and odd field make up a full frame

2.) 720p

1280x720 pixels at 60 full frames per second

For 1080i, an HD-SDI signal (8 bit) sampled at 4:2:2 would require (bits per second):

1920(pixels-x)*1080(pixels-y)*30(frame... per second)*20(10 bits luminance + 10 bits chroma) = 1.2 Gbps

Broadcasters are using an 8-VSB transmission which fits about 19.5Mbps "over the air"

From 1.2Gbps to 19.5Mbps (a compression factor of 63).  They use compression to fit all of the original content into the space available for transmission.  Standard TV channel bandwidth is 6MHz.