... Video Glossary:
1000/1001 - When NTSC color was being introduced into broadcast television, compromises had to be made for it to be compatible with previous black and white systems. The field rate was changed by 1/1.001 – from 60 to 59.94 frames per second. Older B&W TVs could receive color broadcasts and show them in B&W and the new color information could be encoded into the broadcast signal so that the new color TVs would show the broadcasts in color. Today, digital and HD signals have to fit in; 24, 30, and 60 frames/fields per second become 23.98, 29.97, and 59.94 to be compatible with existing NTSC formats and workflows.
1080/24p - Internationally standardized High Definition production format ITU BT 709 has a digital sampling structure of 1920 (H) x 1080 (V) and operates at 24 frames per second progressively scanned. This also loosely describes the format operating at 23.976P.
1080/60i - Standard High Definition production format (SMPTE 274M and ITU 709) with digital sampling of 1920 (H) x 1080 (V), operating in interlaced scan mode at 60 fields per second. Loosely describes the 59.94i system as well.
1280x720 - A high definition digital sampling structure of 1280 horizontal pixels and 720 vertical pixels. All 1280x720 video is progressively scanned: 720p.
16x9 - The aspect ratio standard for HDTV and Widescreen SDTV, with a width of 16 units and a height of 9 units.
1.78 - Using the 16x9 aspect ratio for HDTV and Widescreen SDTV, the ratio of the horizontal screen size to its vertical screen size is 1.78 units wide to 1.0 units high.
1.85 - The most common screen ratio for motion pictures – 1.85 units wide to 1.0 units high.
1920x1080 - A digital sampling structure of 1920 horizontal and 1080 vertical pixels, with images either interlaced (
1080i) or progressive (
1080P).
2:3 Pulldown - For converting 24 frame per second film or 24P video into 59.94 interlaced video. The frame rate is slowed from 24 fps to 23.976 fps (a factor of 1000/1001) and a "3:2" field cadence is created. This is done by taking one frame of the 24 frame source and filling three of the 59.94 fields, with the next frame of the 24 frame source filling only two of the 59.94 fields, the next frame three fields, the next two fields, and so on. This results in four of the 24 frame per second original material fitting into five frames of the destination 59.94i video. Pulldown now describes any combination of 1000/1001 speed change and/or 3:2 cadence creation. The term "pulldown" originates with the mechanical action of the pulldown gate in a telecine pulling each film frame into the imaging area.
2k - Resolution of 2'048 pixels wide. The vertical pixels depend on the aspect ratio.
2.35 - A widescreen motion picture film format of 2.35 units wide by 1 unit high.
23.98 or 23.976 - A video image rate of 23.976 (usually shortened to 23.98) frames per second. A simple 3:2 process will produce standard 59.94 fields per second interlaced video for distribution.
24p - A 24 (aka 23.98) frame progressive video divided in segments of even and odd lines for transmission, storage and display. Though transmitted like an interlaced signal, if treated as a progressive signal it does not create the same harmful artifacts caused by interlace scanning.
29.97p - 29.97 full frames per second progressively captured digital video.
30p - 30 full frames per second progressively captured digital video; more properly 29.97P.
4:1:1 - Both high definition and standard definition systems where the ratio between luminance and chrominance samples is 4:1 – one set of color difference samples (R-Y,B-Y) for every four luminance samples (Y). In standard definition video signals it represents luminance (Y) sampling at 13.5 MHz and R-Y/B-Y channel sampling at 3.75 MHz.
4:2:0 - A digital video format where the two chrominance components are sampled at half the sample rate of luminance; the horizontal chrominance resolution is halved. While this reduces the bandwidth of the video signal by one-third, there is little to no visual difference. This is used by many high-end digital video formats and interfaces.
4:2:2 - Standard definition video signals with luminance (Y) sampled at 13.5 MHz and color difference (R-Y,B-Y) channels each sampled at 6.75 MHz. Now in common usage describing both high definition and standard definition systems with the ratio between luminance and chrominance samples at 2:1 – two sets of color difference samples (R-Y,B-Y) for every four luminance samples (Y).
4:4:4 - Standard definition video signals with all signals (usually R,G,B but also Y, R-Y,B-Y) sampled at 13.5 MHz. Now in common usage describing both high definition and standard definition systems with sampling done on the RGB video signal components.
4:4:4:4 - A digital video sample format with all signals (usually R,G,B but also Y, R-Y,B-Y) sampled at 13.5 MHz., and a key channel added.
4k - Resolution of 4,096 pixels wide. The vertical pixels depend on the aspect ratio.
59.94i - An interlaced video signal with half the total lines of the picture captured and displayed every 1/59.94th of a second.
59.94p - A progressive video signal with all lines of the picture captured and displayed every 1/59.94th of a second.
60i - An interlaced video signal with half the total lines of the picture captured and displayed every 1/60th of a second.
60p - A progressive video signal with all lines of the picture captured and displayed every 1/60th of a second.
720/60p - A High Definition production format (SMPTE 296M) with a digital sampling structure of 1280x720, at 60 frames per second progressively scanned. Also used to describe a 59.94P capture system.
NTSC: National Television Standards Committee
PAL: Phase Alteration Line
SECAM: Systeme Electronic pour Couleur Avec Memoire
XGA: eXtended Graphics Array
SDTV: Standard Definition TV (NTSC, PAL/SECAM)
EDTV: Enhanced Definition TV
HDTV: High Definition TV
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