Composite: The All-Around Choice

Composite video (Acceptable )
This connection is used for connecting the DVD players picture up to a video switching unit, an AV amp or a distribution system (to distribute DVD around the home). It is less good quality than both SCART or SVHS but is still a pretty good quality signal.

RCA phono connectorScart

Chances are, you should probably use composite video interconnect throughout most of your Home Cinema. All VCRs and DVD players have PHONO composite video jacks, as do most of today's TVs and receivers. Composite baseband video suffers from RF interference to a lesser degree than RF video. At baseband video's typical maximum frequency of about 5 megahertz, only low-frequency radio waves can interfere with it. Still, this interference can cause problems similar to those you experience with RF video interconnects, so Philex also double-shields its composite video interconnects to prevent interference through the interconnect.
What about if your display device doesn't have an RGB, component or S-Video input? Well, then we downconvert another notch to composite video. As its name suggests, composite video is a single video signal that is a composite of the black-and-white information (Y) and the colour information (C). This is the same type of signal that at least some of us will have been using prior to the advent of DVD to connect up our laserdisc players or VCRs
  Composite video signals have a number of unavoidable image problems because of inherent limitations of the PAL and NTSC systems. The problem is, once the colour (C) and the black and white (Y) information have been put together, they can no longer be perfectly separated due to fundamental design limitations of the two systems. Whilst a detailed description of these image problems is beyond the scope of this article, there are two specific artefacts which I will mention which are readily demonstrable.
Dot crawl

This occurs on the boundaries between two colours where you can see moving blocks of incorrect colour information. The simplest way of demonstrating this artefact is to look at a test pattern on your TV. If you have access to either Video Essentials or A Video Standard on DVD or Laserdisc, take a look at a colour bar pattern. In particular, look at the vertical edges between the colour bars. You will notice that the edges are smeared, with little blocks of moving colours throughout in a regular pattern. If you then compare this same test pattern via an S-Video input, you will see that these blocks have disappeared, and the edges of the colours are sharp and clear. What applies to a test pattern also applies to normal images that are displayed with composite video. They, too, will exhibit dot crawl at the boundaries of different colours on the screen.

You may be familiar with this artefact when watching a black-and-white image on your TV, particularly if it is an older model. Fine lines in the image result in a purple colour being displayed by the TV. If you look at the test pattern shown on the right via a composite video output, you will readily see if your TV is prone to this artefact. If you look at the same test pattern via an S-Video input, you will not see this artefact.