Defintions of Audio/Video Codecs and Video Terminology : eBay Guides

Defintions of Audio/Video Codecs and Video Terminology for both Computers and Television:

Common Video Terminology and Definitions
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NTSC - National Television Standards Committee
       North American Standard Definition Video format used in USA, Canada & Japan
       This type of signal is ALWAYS broadcast at a frame rate of 29.97 frames per second
       at usually 720 by 480 pixels or 720 by 486 pixels per frame when finally output to your TV.
       The true resolution of an NTSC TV is actually 700 by 525 pixels but not all pixels
       are visible on your TV because those pixels are used for specific technical
       purposes to store timecode, vertical sync information, close captioning
       and other data not visible to the TV watcher.


PAL - Phase Alternate Line
      Standard Definition video format used in most of Europe
      such as Britian, Germany, Italy, Spain, etc.
      This is broadcast in 25 frames per second based upon the 50 cycles per second electrical system
      and 625 lines per frame. Whe the signal finally reaches your European TV, the frames size
      ends up as 704 by 576 pixels. The true resolution of a PAL TV is actually 833 by 625 pixels
      but not all pixels are visible on your TV because those pixels are used for specific technical
      purposes to store timecode, vertical sync information, close captioning
      and other data not visible to the TV watcher.


SECAM - Sequentiel Couleur Avec Memoire (Sequential Color with Memory).
        A color television video signal standard developed in France.
        Similar to PAL, SECAM offers 625 lines and 50 fields (25 frames).
        Used in France, Russia and Eastern Europe.
   
Bandwidth - Bandwidth refers to how much data you can send over the airwaves, through a computer network or over a modem connection.
            For computer networks and modems it is usually measured in bits per second, or "bps."
            You can think of bandwidth as a highway with cars travelling on it. The highway is the network connection
            and the cars are the data. The wider the highway, the more cars can travel on it at one time.
            Therefore more cars can get to their destinations faster. It's the same principle with video data
            the more bandwidth, the more information that can be transferred at one time.  
            Video uses the term Megahertz (or MHz) to measure badnwidth. Many TV signals are still broadcast
            over the airwaves so we use the Millions of Cycles per Second - Megahertz) to signify how wide
            the highway is for the video signal.  The more MHz there is available, the bigger and better
            quality picture we can send to your TV.

Interlaced Video - is a method to reduce the amount of space needed to broadcast a video signal over the airwaves.
                   Each frame is divided into two sets of lines called fields. As each frame is shown, one set of lines is drawn,
                   followed by the other set to fill in the gaps. The field that draws the top line on a frame is called the upper field,
                   the other field is the lower field. The TV display alternates between drawing the even-numbered lines
                   and the odd-numbered lines of each picture. In the PAL and NTSC standards, the lower (even) field is always drawn first.

Non-Interlaced Video - A method of drawing video frames onto a display device at the best quality possible.
                       Pixels (short for Picture Elements) are organized into a group of pixels called a Scan Line
                       that runs from left to the right on a display.  These scanlines are drawn one-right-after-another
                       from top to bottom without interuption. The display quality is much higher than non-interlaced
                       drawing methods, but does take more bandwidth to broadcast over the airwaves or via cable.

Standard Definition - A method to describe the physical size of a TV or Computer display
                      In North America, NTSC generally means 720 by 480 pixels for a video frame
                      while the European PAL and SECAM TV defines a frame as being 704 by 576 pixels.

HTDV (High Definition TV) - A method to describe modern widescreen digital television
                            which is 1920 by 1080 pixels.  There is a lower quality HD standard
                            which is 1366 by 768 pixels that is used in many large plasma screen
                            or projection displays but TRUE HDTV is always 1920 by 1080 pixels.

FPS (Frames Per Second) - A method to describe how many single video frames are displayed in one second
                          so that smooth motion can be attained on a TV or computer display.
                          The higher the frame rate, the smoother the motion, and the better
                          the subjective quality of the video experience.
                          NTSC is 29.97 frames per second while European PAL TV's are 25 frames per second
                          In many cases, a North American visiting Europe or Asia will notice
                          a strobing or flashing effect when watching TV because they are used
                          to the higher frame rate of North American TV.  There are trade-offs between
                          larger frame sizes versus frame rates betweeen NTSC/PAL and SECAM
                          but in the end the decisions to choose what frame rate and format came down
                          to the electrical systems in use at the time TV was invented.  
                          25 fps divides nicely into the 50 cycles per second electrical system of Europe
                          while 30 fps (really 29.97 fps) goes nicely in to the 60 cycles per second
                          electrical system of North America. Almost all film such as 16 mm and 35 mm film
                          is recorded at 24 frames per second. HDTV is slated to have a frame rate of
                          60 frames per second progressive scan which will be ideal for high-end cinema,
                          sports video and other events that have lots of motion.

Aspect Ratio - The relationship between the width and height of a video frame.
               Standard Definition is by definition 4:3 aspect ratio which is an
               almost square picture which lends itself nicely to news programming
               and drama with plenty of closeups.
               HDTV is by default WideScreen at 16:9 which is almost twice as wide
               as it is high thus making for an almost cinema-like experience.
               This is great for epic sagas and Hollywood films.  

If you're looking to buy a big fancy for a TV, look for one that is TRUE High Definition
with an aspect ratio of 16:9 at 1920 by 1080 pixels NATIVE resolution
preferably using LCD, Plasma or Rear Projection technology (in that order)

Make sure the TV has ALL of the following connectors at the back:
HDMI, DVI, RGB Analog VGA, Component RGB/YBrCr RCA and S-Video connectors.
This will give you the greatest flexibility to connect X-BOX'es, Playstations,
computers, DVD players, Satellite dishes, PVR's, VCR's and other devices.

Speakers should by 5.1 surround with fibre-optic connectors on your amplifier
and media playback device which will give you the BEST sound quality.

Use Oxygen Free speaker cables with gold-plated connectors such as those from
Mogami, Monster, Acoustic Research, Radial Engineering and other
high quality brands for speaker cable.