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:
“These people figured video was the Lord’s preferred means of communicating, the screen itself a kind of perpetually burning bush. “He’s in the de-tails,” Sublett had said once. “You gotta watch for Him close.””
—William Gibson (b. 1948)
“In frames as large as rooms that face all ways
And block the ends of streets with giant loaves,
Screen graves with custard, cover slums with praise
Of motor-oil and cuts of salmon, shine
Perpetually these sharply-pictured groves
Of how life should be.”
—Philip Larkin (1922–1986)