Editing Broadcast television systems (section)

==== Frames ====
{{Main|Film frame}}

Ignoring color, all television systems work in essentially the same manner. The monochrome image seen by a camera (later, the [[Luma (video)|luminance]] component of a color image) is divided into horizontal ''scan lines'', some number of which make up a single image or ''frame''. A monochrome image is theoretically continuous, and thus unlimited in horizontal resolution, but to make television practical, a limit had to be placed on the [[Bandwidth (signal processing)|bandwidth]] of the television signal, which puts an ultimate limit on the horizontal resolution possible. When color was introduced, this limit necessarily became fixed. All analog television systems are ''[[Interlaced video|interlaced]]'': alternate rows of the frame are transmitted in sequence, followed by the remaining rows in their sequence. Each half of the frame is called a ''[[Field (video)|video field]]'', and the rate at which fields are transmitted is one of the fundamental parameters of a video system. It is related to the [[utility frequency]] at which the [[Electric power distribution|electricity distribution]] system operates, to avoid flicker resulting from the [[Beat (acoustics)|beat]] between the television screen deflection system and nearby mains generated magnetic fields. All digital, or "fixed pixel," displays have [[progressive scan]]ning and must [[Deinterlacing|deinterlace]] an interlaced source. Use of inexpensive deinterlacing hardware is a typical difference between lower- vs. higher-priced [[Flat-panel display|flat panel displays]] ([[Plasma display]], [[Liquid-crystal display|LCD]], etc.).

All [[film]]s and other filmed material shot at 24&nbsp;frames per second must be transferred to video [[frame rate]]s using a [[telecine]] in order to prevent severe motion jitter effects. Typically, for 25&nbsp;frame/s formats (European among other countries with 50&nbsp;Hz mains supply), the content is [[576i#PAL speed-up|PAL speedup]], while a technique known as "[[Three-two pull down|3:2 pulldown]]" is used for 30&nbsp;frame/s formats (North America among other countries with 60&nbsp;Hz mains supply) to match the film frame rate to the video frame rate without speeding up the play back.