Audio / Video Leads - Component Video / RGB / YUV
Component is rarely seen on DVD players but will start to
appear with increasing regularity as projection systems and Plasma become more
popular. Basically, the picture is spilt to it's component parts and passed via
three different connectors to the TV/Projector. Component can only be used when
there is a dedicated component input on the TV/Projector.
DVD stores a component video signal in digital format. Since this is the native
video format that is stored on DVD, this is also the best format to use to display
the picture, if your equipment is capable of dealing with this type of signal.
In Australia, virtually no equipment exists that is compatible with a component
signal, though there is some that is compatible with an RGB signal. Many DVD
players are capable of converting their native component signal to an RGB signal,
but this varies on a player-by-player basis.
Problems with the Component signal
As discussed above, DVD stores its video information in the component form, but
unfortunately the great majority of us cannot take advantage of this format.
The designers of the DVD format anticipated this, and made allowances for it
in the specification. All DVD players are capable of downconverting a component
video signal into a more suitable format for display on the current generation
of consumer display devices. The first such downconversion step is to S-Video,
which is a connector that will always be found on any DVD player.
What comes out of a TV camera?
A TV camera outputs a video signal that is split into the three primary colours;
red, green and blue (RGB). The entire colour spectrum can be represented by varying
intensities of these three colours. This signal needs to be modified before it
can be further processed or broadcast. Why?
Problems with the RGB signal
The RGB signal has two specific problems associated with it in the professional
video world. Firstly, it has a very high bandwidth. Secondly, the colour and
the black and white picture information are combined within the RGB signal. This
is dealt with in the professional video world by converting the RGB signal into
a component signal, also referred to as a YPbPr or YCbCr signal. The Y component
of this signal is the black and white information contained within the original
RGB signal. The Pb and Pr signals are colour difference signals, which are mathematically
derived from the original RGB signal. For our purposes, it is sufficient to understand
that the Y signal contains full bandwidth black and white picture information,
and the colour difference signals contain bandwidth reduced colour information.
It is important to realize that component video output and RGB video output are
not the same and are not directly compatible with each other.
Component Video / RGB / YUV Connections
- Labelled as: Either RGB or YUV, YPbPr, YCbCr or Y/B-Y/R-Y.
- Some U.S. and Japanese players output interlaced component YUV video via
3 Phono or BNC connectors.
- European players usually provide RGB via scart or 3 Phono.
- 80% of European TV may lose control of colour saturation.
- Note: RGB (European) and YUV (US) are non-compatible variants of component video.
A transcoder is needed to link up the YUV player and RGB equipment.
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