Video formats comparision

To understand the different common video formats and how they relate to each other we need to we can create a table of commonly used video formats. We start with RGBHV at the top and proceed down the list to composite video and RF signals used in cable TV.

Video format comparision table

Signal Format	Coax Wires	Quality	Encoding Requirements	Decoding Requirements	Advantages	Common uses
R G B H V	5	Highest	None	None	Original image, highest bandwidth, very suitable for high resolution computer graphics	PC VGA, computers
R G B S	4	High	Combination of sync	Separation of sync	Same as above	SCART RGB, computers, DVD players in Europe
R GS B	3	High	Combination of sync and summing it to green video component	Stripping of sync from green channel plus separating H & V	Same bandwidth if display strips sync properly	Computers
Component (Y, B-Y, R-Y) (YPbPr)	3	Very Good	Simple matrix encoder, combine syncs and add them to Y channel	Simple matrix decoder, strip sync from Y channel	Nearly as good as RGB but requires good matrix design	Professional video editing, HDTV, DVD players in USA
S-video	2	Good	Matrix encoder, filtering and modulation of color signals to subcarier for S component, combination of sync signals and summing them to Y channel	Synchronous detector plus matrix decoder & sync processing	Requires only two cable connections	DVD, S-VHS, computer TV output, DV video out
Composite	1	Low	Matrix encoder, filtering and modulation of color signals to subcarier, combination of sync signals and summing everything together	Complete decoder with Y & C comb filtering, synchronous detector, matrix, and sync processing	Requires only one cable connection & can be used to modulate an RF transmitter	Almost every video equipment supports, very widely used
RF	1	Lowest	Same as for composite video plus modualtion to RF subcarrier	Demodulation and afer thas same as for composite video	Requires only one cable connection for both video and audio. Many video channels can be carried in one cable.	TV broadcasts, cable TV

Comments on video formats

Within the RGB formats, the only issue is sync processing. However, dont be misguided by thinking that sync processing is a minor issue. There were never any significant standards established for constructing composite sync for the myriad of computer signal formats. It is possible to construct composite sync (and many computer manufacturers used it for years) for computer graphic outputs, those might cause sometimes compatibility problems. If you are using RGsB signals, removal of sync from the green channel can affect the performance of the green channel or the proper operation of the displays black level controls.

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