Any docs or links for Video Encoder ?

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ayeong

Joined: 01 Jan 1970
Posts: 99

21 Apr 2003 16:06 Any docs or links for Video Encoder ?

Hi guys,

Anybody got any links or documents that relate to video encoder that convert CCIR-601 digital data to analog RGB or NTSC or PAL comptabile signal ?

Currently, I'm looking at a schematic utlizing an Analog Devices video encoder (ADV7171) which can be located at the following link

http://www.analog.com/Analog_Root/productPage/productHome/0%2C2121%2CADV7171%2C00.html

First of all, I don't even understand what is the input meant (CCIR-601) data as well as the encoding process.

Thus, any links or docs regarding the protocol will be greatly appreciate.

Thanks

Best Regards

dar_b1

Joined: 09 Jan 2003
Posts: 2

21 Apr 2003 23:30 Re: Any docs or links for Video Encoder ?

i found the standard at philips site (pages 1-16):[url]
http://www.semiconductors.philips.com/acrobat/various/CCIRDOCS.pdf
[/url]
usually this standard goes with ccir 656 (pages 18-31)

additional info:[url]
http://www.semiconductors.philips.com/acrobat/various/COLORSPC.pdf
[/url]

this standard defines digital video coding standards for video broadcast:
it defines 3 video signals: Y, Cb, Cr (derived from the common signals R, G, B) and digital values for common colours
later it defines 2 encodeing parametrs 13.5 and 18MHz for 2 systems 50Hz and 60Hz and sampling format

for instance for 13.5MHz in system 50Hz/625 lines (common system for europe) there should be 864 y signals (720 of the active signals) in a line

sampling format: 4:2:2 means that y sampling appear in every pixel and Cb, Cr sampling appear only at every second pixel

the Y rate is 13.5MHz and Cb, Cr rates are 6.75MHz each, total 27MHz
the input for the video encoder may be 1 multiplexed bus (Y, Cb, Cr) rate 27MHz or 2 buses: for Y rate 13.5MHz and for Cb, Cr rates total 13.5MHz

the timing of the Y, Cb, Cr signals are also coordinate to analogue video signal timing

standard 656 continue and defines also parallel and digital interfaces for this standard