Editing is primarily about telling a story, using pictures and sound to entertain, inform or educate. But if the quality, that is technical quality, is sub-standard the story may never get told. It could be that a broadcaster will not transmit a programme due to illegal colours being produced, or a client might object to distortion on audio. Whatever the reason, video editors need to have an understanding of the television system and the engineering criteria that apply to video and audio.
The interlaced scanning system
Video images are generated using an interlaced scanning system. An image is scanned from left to right and from top to bottom. Each complete scan from top to bottom is known as a field, which is designated as field 1 ...