RGVHV to Component Video (YPrPb)

[Mike]

Hi, do you guys know what is the formula of adding H and V sync of VGA
to Y signal?

I know for 480p, Y=0.299R + 0.587G + .5B and for 720p/1080i,
Y = 0.2126R + 0.7152G + 0.0722B, but I don't know how to add H and V
sync on Y signal. What's the formula?

Thanks

 

[Glenn Gundlach]

Hi, do you guys know what is the formula of adding H and V sync of VGA
to Y signal?

I know for 480p, Y=0.299R + 0.587G + .5B and for 720p/1080i,
Y = 0.2126R + 0.7152G + 0.0722B, but I don't know how to add H and V
sync on Y signal. What's the formula?

Thanks

Typo on the 480p matrix. B should be 0.114. Adding composite sync is
trivial. The coefficient depends on the amplitude of your sync. Typical
levels have the video at 700 mv and sync at 300 mV (286mV for broadcast
NTSC with 7.5IRE setup). BUT making composite sync from H and V is not
trivial if you have to maintain interlace. For progressive sync it
might be OK to invert the polarity of H sync during V.
GG

 

[theone]

Typo on the 480p matrix. B should be 0.114. Adding composite sync is
trivial. The coefficient depends on the amplitude of your sync. Typical
levels have the video at 700 mv and sync at 300 mV (286mV for broadcast
NTSC with 7.5IRE setup). BUT making composite sync from H and V is not
trivial if you have to maintain interlace. For progressive sync it
might be OK to invert the polarity of H sync during V.
GG

Thanks I will double check the 480p matrix.

Do you have more detailed information on how to add H and V on to Y?

BTW, I have heard some vga to component transcoders are only good for
480p, do you guys know why is that? Is it only because the color
martix? or the sync in 480p/720p/1080i are different? Can anyone
explain to me in detail or when can I found the detailed information?
any HDTV spec on the net?

Thanks

 

[Glenn Gundlach]

Thanks I will double check the 480p matrix.

Do you have more detailed information on how to add H and V on to Y?

BTW, I have heard some vga to component transcoders are only good for
480p, do you guys know why is that? Is it only because the color
martix? or the sync in 480p/720p/1080i are different? Can anyone
explain to me in detail or when can I found the detailed information?
any HDTV spec on the net?

Thanks

Not much to check on those matrix numbers. They add up to 1 so Blue has
to be 0.114. As for transcoders, you're limited by the speed of the
summing amplifiers. I know HDTV transcoders work in analog because it
was part of a project I did 5 years back.

The sync for 480i is bi level (negative going only). I believe its the
same for 480p. I know that for 720p and 1080i its trilevel +/- 300mV
from black (nominally 0V) with the reference timing where tri-level
crosses 0.

You should be able to find all sorts of good stuff at Teronix

http://www.tek.com/.

Also check Gennum and Elantec.

http://www.atsc.org/ has standards definitions. Many for free.

GG

Always make NEW mistakes.