COMPOSITE VIDEO: 
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A type of analog video signal in which all information consists of three
source signals — Y (luminance, or brightness/contrast), U and V (which carry
the color information). These three signals are mixed together (modulated) 
and carried on a single signal (multiplexed onto a carrier signal). This 
is the analog video Signal format used by televisions in the United States. 

When you see "YUV" in the status readout in a video editing program, it is
telling you that you are working with composite video or S-Video signals. 
It is not a "compression" format like MPEG. 


S-VIDEO: 
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"Separate Video" - This analog video signal is similar to Composite Video, 
but the Y channel (luminance) is carried on a separate conductor than the 
U and V channels (color information). This eliminates a type of distortion 
called "crosstalk" that can degrade the picture quality. 

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NTSC is an acronym for the National Television System Committee. The NTSC is
responsible for setting television and video standards as used in the United
States, Canada, Japan, South Korea and several countries in Central and South
America (in Europe and the rest of the world, the dominant television
standards are PAL and SECAM). The NTSC standard for television defines a 
composite video signal with a refresh rate of 60 half-frames (interlaced) 
per second. Each frame contains 525 lines and can contain 16 million different
colors. 

The NTSC standard is incompatible with most computer video standards, which
generally use RGB video signals. However, you can install a special video
adapter into your computer that will convert NTSC signals into computer video
signals and vice versa. 
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