Video Frames
Historically, video frames were represented as analog waveforms in which varying voltages represented the intensity of light in an analog raster scan across the screen. Analog blanking intervals separated video frames in the same way that frame lines did in film. For historical reasons, most systems used an interlaced scan system in which the frame typically consisted of two video fields sampled over two slightly different periods of time. This meant that a single video frame was usually not a good still picture of the scene, unless the scene being shot was completely still.
With the dominance of digital technology, modern video systems now represent the video frame as a rectangular raster of pixels, either in an RGB color space or a color space such as YCbCr, and the analog waveform is typically found nowhere other than in legacy I/O devices.
Standards for the digital video frame raster include Rec. 601 for standard-definition television and Rec. 709 for high-definition television.
Video frames are typically identified using SMPTE time code.
Read more about this topic: Film Frame
Famous quotes containing the words video and/or frames:
“We attempt to remember our collective American childhood, the way it was, but what we often remember is a combination of real past, pieces reshaped by bitterness and love, and, of course, the video past—the portrayals of family life on such television programs as “Leave it to Beaver” and “Father Knows Best” and all the rest.”
—Richard Louv (20th century)
“... though it is by no means requisite that the American women should emulate the men in the pursuit of the whale, the felling of the forest, or the shooting of wild turkeys, they might, with advantage, be taught in early youth to excel in the race, to hit a mark, to swim, and in short to use every exercise which could impart vigor to their frames and independence to their minds.”
—Frances Wright (1795–1852)