Digital Video

Digitization of Video Signals

Sampling: Quantization: Represent color in numbers, usually 1 byte per color channel

Advantages
Disadvantages
Chroma Subsampling
Since humans see color with less spatial resolution than they see black and white, it makes sense to decimate the chrominance signal 4:2:0 along with other schemes commonly used in JPEG and MPEG .

CCIR
CCIR-601 standard for component digital video become standard ITU-R-601, an international standard for professional video applications
Adopted by certain digital video formats including the popular DV video.
The CCIR 601 standard uses an interlaced scan so each field has only half as much vertical resolution
CCIR 601 525/60 NTSCCCIR 601 625/50 PAL/SECAMCIFQCIF
Luminance Resolution720 x 480720 x 576352 x 288176 x 144
Chrominance Resolution360 x 480360 x 576176 x 14488 x 72
Color Sub-sampling4:2:24:2:24:2:04:2:0
Aspect Ratio4:34:34:34:3
Frames/sec60503030
InterlacedYesYesNoNo

CIF
Format specified for lower bit rate, about the same as VHS quality
Uses progressive scan
QCIF stands for Quater-CIF
All the CIF/QCIF resolutions are evenly divisible by 8
All except 88 are divisible by 16
This provides convenience for block-based video coding in H.261 and H.263

HDTV

High-Definition Television is high resolution digital television (DTV)
combined with Dolby Digital Surround Sound (AC-3)
2 main DTV standards
DVB-T
based on MPEG-2 for video, audio and data transmission
w x h pixelsAspect RatioPicture rate
HDTV1920x108016:925p, 50i
1440x1080
1280x1080
1280x720
720x576
SDTV720x57616:9, 4:325p, 50i
544x576
480x576
352x576
704x576

ATSC
widthheightAspect RatioPicture rate
1920108016:960i 30p 24p
128072016:960i 30p 24p
70448016:9, 4:360i 60p 30p 24p
640480 4:360i 60p 30p 24p
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