Video Media
Department of Computer Education
KMUTNB
Multimedia
Video features
Video
Mediain a range of
Multimedia application
• Entertainment
– Broadcast television and VCR/DVD recordings
• Interpersonal
– Video telephony and videoconferencing
• Interactive
– Windows containing short video clips
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Multimedia
Video Media
Broadcast Television
• 525 Lines
– NTSC American standard
– 60 Fields / second
– 30 Frames / second
• 625 Lines
– PAL European standard /CCIR/SECAM
– 50 Fields / second
– 25 Frames / second
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Multimedia
Video Media
Scanning illustrated
1
2
3
4
5
6
Voltage
720 pixel
720 Sample
1
2
Time
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4
5
6
4
Multimedia
Video Media
Type of Scanning
• Progressive = every scan line done in turn.
• Interlaced = every other scan line done.
– Creates two fields: odd field and even field.
– NTSC: 262.5 lines per field at 60 fields per sec.
– PAL: 312.5 lines per field at 50 fields per sec.
• Fields are separated in time.
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Multimedia
Video Media
Computer & TV
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1 TV Frame = 2 Field
1 Computer Frame
interlaced scan
Progressive scan
6
Multimedia
Video Media
Computer & TV
Computer
1 Frame
……. …..
62
5
1 2 3 4 5 6 7 .. …..
……. …..
…….
1 3 5 7 .. ….. 625 2 4 6 8 62
……
4
312.5 Odd
312.5 Even
Field
Field
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Television
1 Frame
7
Computer 2
Computer 1
Television
……. …..
1 2 3 4 5 6 7 .. …..
……. …..
1 2 3 4 5 6 7 .. …..
……. …..
62
4
62
5
1 3 5 7 .. ….. 625 2 4 6 8 62
……
4
312.5 Even
Field
312.5 Odd
Field
8
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…….
Multimedia
Video
Media
Video capture with both field
Multimedia
Video
Media
Video capture with one field
Television
..312
…….
Discard
MPEG 1 ( VCD)
….
1 2 3 4 5 6 7 ..
……. …..
1 3 5 7 .. ….. 625 2 4 6 8 62
……
4
312.5 Even
Field
312.5 Odd
Field
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Computer 1
From Interlaced to Progressive system
discard resolution in half
9
Multimedia
Video
Media
Scanning Sequence in TV
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Interlaced scanning principles
10
Multimedia
Video
Media
Scanning Sequence in TV
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525-line systems : 262.5 each field, 240 visible
625-line systems : 312.5 each field, 288 visible
11
Safe Frame
To TV
From Camera View Finder
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To
Digital File
12
Multimedia
Video Media
Broadcast Television
• Video resolution and quality
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Multimedia
Video
Media
3 Main Properties of a Color
• Hue:
The actual color of the source,
each color has a different
frequency/wavelength and eye
determines the color from this.
• Saturation:
The strength of
vividness of the color, a pastel color has
a lower level of saturation than a color
such as red.
• Brightness :
The amount of energy
that stimulates the eye and varies on a
gray scale from black (lowest) Through
to white(highest)
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Multimedia
Video
Media
Luminance & Chrominance
• Luminance : is used to refer to the
brightness of a source, and the hue and
saturation
• Chrominance: is used to refer to the color
characteristics.
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Multimedia
Video Media
TV Color Signals
Traditional monochrome TV
Luminance
White --> Black
Component Signal
Chrominance
Magnitude of the 3 electrical signals
that energize the R,G,B Phosphors
0.299R + 0.587G + 0.114B
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Multimedia
Video
Media
Composite Video Signals
Ys = 0.299 Rs + 0.587 Gs + 0.114 Bs
Cr = Rs - Ys
Cb = Bs - Ys
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Ys is amplitude of luminance signal
Rs, Gs, Bs is magnitude of 3 color
component signals
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Multimedia
Video
Media
Composite Video Signals
R
G
B
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Cr
Ys
+
-
monochrome
Cb
Composite Video Signal
+
Rs
-
Gs
+
Bs
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Multimedia
Video
Media
Chrominance components
From Ys, Cr, Cb
PAL : Y = 0.299 R + 0.587 G + 0.114 B
U = 0.493 (B - Y)
V = 0.877 (R - Y)
NTSC : Y = 0.299 R + 0.587 G + 0.114 B
I = 0.74 (R-Y) - 0.27(B-Y)
Q = 0.48 (R-Y) + 0.41(B-Y)
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Multimedia
Video Media
Signal bandwidth
Baseband spectrum of color television signals in NTSC system
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NTSC : Y = 4.2 MHz
I = 2 MHz
Q = 1 MHz
20
Multimedia
Video Media
Signal bandwidth
Baseband spectrum of color television signals in PAL system
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PAL : Y = 5.5 MHz
U = 3 MHz
V = 3 MHz
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Multimedia
Multimedia
Summary
Digital Video Frames
•
•
•
•
Almost always progressive
3 planes of pixel values (Y, U, and V)
Pixel depth
Geometry of each plane: width x height
– Chrominance is generally subsampled.
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Multimedia
Video Media
Digital video
• The visual perception of the eye have less
sensitive for color than luminance
• This means that 2 chrominance signals can
tolerate a reduced resolution relative to that
used for the luminance signal
• Saving in terms of resulting bit rate and
transmission bandwidth
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Multimedia
Video
Media
Digital video standard
• International Telecommunications Union
Radiocommunications Branch (ITU-R)
• Formerly known as the Consultative
Committee for International
Radiocommunications (CCIR)
Recommendation CCIR-601
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Multimedia
Video MediaCCIR-601
• Standard established for digitizing NTSC
and PAL signals
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Digital
Component
Analog
Counterpart
CCIR-601
Recommendation
Height
Lines
Width
Continuous
voltage changes
along scan line.
NTSC: 480
PAL: 576
Sample at 13.5 MHz
Results in 702 pixels
Recommended 720
Pixel depth
Voltage range.
Gamma-corrected
8-bit sample.
Chrominance
subsampling
Bandwidth
differences
4:2:2, 4:2:0, 4:1:1
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Multimedia
VideoVideo
Media
Color Storing
The visual perception of the eye have less sensitive for color than luminance
Cr
Y 1,
1
1,
Cb
2,
1
2,
3,
1
3,
4,
1
4,
Cr
Y 1,
1
1,
2
1,
3
1,
2
2,
3
2,
2
3,
3
3,
2
4,
3
4,
4
4
4
4
From Source
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Cb
2,
1
2,
3,
1
3,
4,
1
4,
2
1,
3
1,
2
2,
3
2,
2
3,
3
3,
2
4,
3
4,
4
4
4
4
Storing method
26
Multimedia
Video
Media
Video Color Playback
Cr,Cb
Cr
Y 1,
1
1,
Cb
2,
1
2,
3,
1
3,
4,
1
4,
Cr
Y 1,
1
1,
2
1,
3
1,
2
2,
3
2,
2
3,
3
3,
2
4,
3
4,
2
1,
3
1,
4
4
4
4
4
Cr,Cb
3,
Cb 1, 1, 3,
1, 1 1, 1 3, 1 3, 1
3,
1 1
1
1
2, 3, 4, 3, 2
3,
2
1 3,
1 4,
1 3,
2,
3
3,
3
2 3,
2 4,
2 3,
2,
4
4
3
3
3
2, 3, 4,
4
4
4
Playback process
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Multimedia
Video
Media
Video Digitization Formats
 4:2:2 means 2:1 horizontal downsampling, no
vertical downsampling.
(Think 4 Y samples for every 2 Cb and 2 Cr samples in a scanline.)
 4:1:1 ought to mean 4:1 horizontal downsampling, no
vertical.
(Think 4 Y samples for every 1 Cb and 1 Cr samples in a scanline.)
It is often misused to mean the same as 4:2:0 .
 4:2:0 means 2:1 horizontal and 2:1 vertical
downsampling.
(Think 4 Y samples for every Cb and Cr samples in a scanline.)
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4:2:2
• Use in television Studio
• For every 4 luminance samples, take 2
chrominance samples from odd lines
and 2 from even lines.
• Chrom. planes just as tall, half as
wide.
• JPEG does this.
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Multimedia
Video Media
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Sample positions with 4:2:2 digitization format
Multimedia
Video Media
4:2:2
30
Cr
Y 1,
1
1,
Cb
2,
1
2,
3,
1
3,
4,
1
4,
2
1,
3
1,
2
2,
3
2,
2
3,
3
3,
2
4,
3
4,
Cr
Y 1,
Keep 2 odd
1
1,
Keep 2 even
2
1,
3
1,
4
4
4
4
4
From Source
Storage size Y+Cr+Cb
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Multimedia
Video Media
4:2:2
Every 4 pixel
Cb
2,
1
2,
3,
1
3,
4,
1
4,
2
2,
3
2,
2
3,
3
3,
2
4,
3
4,
4
4
4
Storing method
Storage size Y+0.5Cr+0.5Cb
Sample positions with 4:2:2 digitization format
31
4:2:0
• Used in Digital Video broadcast
application
• 2 chrominance samples for every 4
luminance samples, odd lines only.
• Chrominance halved in both directions.
• MPEG generally does this.
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Multimedia
Video Media
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Sample positions with 4:2:0 digitization format
Multimedia
Video Media
4:2:0
33
4:2:0
Every 4 pixel
Cr
Y 1,
1
1,
Cb
2,
1
2,
3,
1
3,
4,
1
4,
2
1,
3
1,
2
2,
3
2,
2
3,
3
3,
2
4,
3
4,
Cr
Y 1,
Keep 2 odd
1
1,
Keep 0 even
2
1,
3
1,
4
4
4
4
4
From Source
Storage size Y+Cr+Cb
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Multimedia
Video Media
Cb
2,
1
2,
3,
1
3,
4,
1
4,
2
2,
3
2,
2
3,
3
3,
2
4,
3
4,
4
4
4
Storing method
Storage size Y+0.25Cr+0.25Cb
Sample positions with 4:2:0 digitization format
34
Cr
Y 1,
1
1,
2
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Cb
2,
1
2,
2
Play
Cr
Y 1,
1
4:2:0
Cb
1,
2
4:2:0 playback process
Multimedia
Video Media
2,
1
2,
2
35
Multimedia
Video Media
4:2:0
• To avoid flicker effect with the chrominance
signal
– the receiver uses the same chrominance value
from the sampled lines for the misslines
• Large-screen flicker effects are often reduced
by
– storing the incoming digitized signals of each field
in a memory buffer
– Double the normal rate 100/120 Hz then used
with the stored set of signals used for the 2 field
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•
•
•
•
•
HDTV
High-Definition Television
Older 4/3 aspect ratio 1440 x 1152 pixels
newer 16/9 aspect ratio 1920 x 1152 pixels
1080 visible lines per frame
4:2:2 digitization for studio application
– Frame rate 50/60 Hz
• 4:2:0 digitization for broadcast application
– Frame rate 25/30 Hz
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Multimedia
Video Media
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SIF
• Source Intermediate Format
• Used in Video Cassette Recorders (VCR)
• Used Half spatial resolution in both
horizontal and vertical in 4:2:0 format
• Frame rate 30 Hz for 525 line, 25 Hz for 625
line
• Progressive (non interlaced) scanning
• The receiver estimated by interpolating
between each pair of value missing line
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Multimedia
Video Media
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Multimedia
Video Media
SIF and CIF
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Sample positions for SIF and CIF
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Multimedia
Video Media
SIF and CIF
Cr
Y 1,
1
1,
Cb
Cb
2,
1
2,
3,
1
3,
4,
1
4,
2
1,
3
1,
2
2,
3
2,
2
3,
3
3,
2
4,
3
4,
4
4
4
4
From Source
Storage size Y+Cr+Cb
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Cr
2,
Y 1, 2, 2 3,
1 2
1
1,
3
3,
3
Storing method
Storage size 0.25Y+0.0625Cr+0.0625Cb
Sample positions with 4:2:0 digitization format
40
Multimedia
Video Media
SIF and CIF
Cb
Cr
2,
Y 1, 2, 2 3,
1 2
1
1,
3
3,
3
Storing method
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Cb All 2,2
Cr All 2,2
Y 1, 1,
1 1,
1
1,
1 1,
1
1,
3
1,
3
3
1,
3
3,
1
3,
3,
1
3,
1
3,
3
3,
1
3,
3
3,
3
3
Playback
Sample positions with 4:2:0 digitization format
41
Multimedia
Video
Media
When Capture from Video Tape
2,
Y 1, 2, 2 3,
1 2
1
1,
3
3,
3
From Video Tape
or Home use Quality Signal
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Cr
Y 1,
1
1,
3
Cb
3,
1
3,
3
Capture to Computer
Video
Tape
360x288
Video
Clip
360x288
Sample positions with 4:2:0 digitization format
42
Multimedia
Video Media
CIF
• Common Intermediate Format
• Defined for use in Videoconferencing
applications
• Typical bit rate used is a single 64 kbps ISDN
channel
• Can multiple channel for high bit rate
4CIF: Y= 720 x 576
Cb = Cr = 360 x 288
16CIF: Y= 1440 x 1152
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Cb = Cr = 720 x 576
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CIF
360x288
CIF
64 kbps
64 kbps
64 kbps
CIF
64 kbps
360x288
720x576
CIF CIF
CIF
CIF
256 kbps
256 kbps
CIF
CIF
CIF CIF
720x576
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In Videoconference Application
Multimedia
Video Media
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Multimedia
Video
Media
Common Digital Video Sizes
•
•
•
•
•
•
CCIR-601720x480 4:2:2, 4:2:0
SIF
360x240 4:2:0
CIF
360x288 4:2:0
4:3 HDTV
1440x1152 4:2:2, 4:2:0
9:16 HDTV
1920x1152 4:2:2, 4:2:0
4CIF, 16CIF, QCIF
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Multimedia
Video
Media
PC video digitization formats
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Multimedia
Video
Media
Multimedia Communication Standards
• H.320 Video Teleconferencing Standard
– Visual Telephone System over N-ISDN
• H.324
– low bit rate multimedia communication terminal
for PSTN and Mobile Radio
• H.321, H.310
– high resolution broadband audiovisual
communication systems via B-ISDN
• H.322, H.323
– narrowband visual telephone services on LAN
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Multimedia
Video Media
Referrence
• Multimedia communication Application, Networks, protocols and
standards; fred halsall. Chapter 2 Multimedia information
representation page 96-113; ISBN 0201398184
• http://www.sce.carleton.ca/courses/96502
• http://www.crs4.it/~luigi/MPEG/ccir601.html
• http://www.broadcastengineering.com/archives/0198/199801be
15.html
• http://www.cs.unc.edu/~kmp/classes/sp01/comp249
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