video basics introduction ---- video industry video imaging ---- video scan, aspect ratio color and...
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Video Basics
Introduction ---- video industry
Video Imaging ---- video scan, aspect ratio
Color and Composite & component systems
From Analog To Digital Video
Spatial Conversions ---- video formats
Temporal Conversions
Mixing And Keying
Onde temos vídeo?
C a b le N e tw o rk
D V B - S d o w n s t r e a m ( m a x 9 0 M b p s )D S S
D V B - C d o w n s t r e a m ( m a x 4 0 M b p s )O p e n C a b le
1 . S a t e l li te ( f a s t P S T N / I S D N2 . C a b l e M o d e m ( Q P S K , T C P / I P ™ f o r P S T N / I S D N m o d e m3 . S D S L / A D S L / V D S L … ..
I E E E 1 3 9 4 / U S BE t h e r n e t 1 0 M b p s …..
S a te llit e
In ter a c tio n C h a n n e l
H o m e C o n n e ct io n
T e rre s tr ia l ( P l u g & P l a y , h i g h - d a t a - r a t e )
( 1 - w a y / 2 - w a y )
DTV set
DV B - T / A T S C
DS TB
Cab l e M o dem
Di recP C /Di recDuo
Provedores de vídeo
Service P rov is ion
TC P / IP
D V B - TD V B - S
(h igh speed BB )D V B - C
(C ab le M odem )
H FC(Fu ll S erv ice
Netw ork)
PO T S(xD SL access)
Residen tia l LAN(IR, RF, W ired)
Hybrid Services
D S T B
W ireless C able(M M D S)
Aplicações de vídeo digital‚
’ ' ˆ ¯
¯
* Ì - - ‚ ‘ •
. .
.
… e )
…
. . .. . .
S e t - T o p B o xR C
Surfar, email, homebanking
Pay-per-view
Video telefoniaMultimídia sob demanda
Vantagens de vídeo digitalOpen Architecture video systems, meaning the existence of video at multiple spatial, temporal, and SNR resolution within a single scalable bitstream
Interactivity
Variable-rate transmission on demand
Easy software conversion from one standard to another
Integration of various video applications
Editing capabilities, such as cutting and pasting, zooming
removal of noise and blur
Robustness to channel noise and ease of encryption
…...
Sistema de vídeo do futuro
De s c ra m b le r OSD
T ran s p ort
N T SC / PALEnc od e r
CP U
M PEG - 2Vi deo
T ra fficC on t rol ler
M PEG - 2Au di o
D i g i t a l D e c o d e r C h i p
T u ner
T u ner
T u ner
Sa te l l i te
Ca b l e
T e rr estr ia l
QP SKDe m o d
QAMDe m o d
CO F D MDe m o d
FE C
FE C
FE C
SD R A M
F las h /EPR OM
SD R A M VC X O
P1 3 9 4I R B u ffe r& Am p R S 2 3 2 I rD A Po rt
M od emV- Ser i es
Sma rt Ca rdB u ff er P1 2 8 4 SC S I
I 2 C
R FM odul ator
SEC AMEnc od e r
(o p ti on al )
DA C s+ F ilte rs
L
R
AV
Sw itc h
R G B or Y/ Can d C VBS
Gra ph i c s
AN D/ OR
AD C
AN D/ OR
I F
I F
QP SKM o d
FEC
AD C
D u alAD C
Imagens e vídeo - definições
Imaging: normal photography, X-rays, electronic documents, electronic still pictures, motion pictures, TV
Video: a sequence of still pictures of a scene taken at various subsequent intervals in time
Scanning: a form of sampling of a continuously varying two-dimensional signal
Resolução de vídeoViewing Ratio (VR):
VR = d /PH d= viewer’s distance from the screenPH= picture height
Visible pixels = 3440 /VR
Pixel (Pel) : the smallest detail that can be reproduced in a picture is about the size of a picture element
System Line or pixels/PH VR
NTSC television 483 7.2
HDTV 1080 3.2
Computer display 768 <4.5
Minimum viewing rates
Taxa de refresh e flickerPersistence of vision, causes the visual system responds slowly to
rapid changes of illumination
Flicker: if the illumination varies cyclically at a low frequency, the eye may perceive an annoying effect
Refresh Rate: the light output of display devices decays after a short time, and therefore must be refreshed periodically to maintain the effect of steady illumination
System Refresh rate (Hz) VR
NTSC television 60(59.94) 7
Computer display 72 1-2
Motion picture theater 48 5-10
Display refresh rates
scanear uma imagem de vídeonão entrelaçado
scanear uma imagem de vídeoentrelaçado
Relação largura/altura
IAR (Image Aspect Ratio )is defined as the ratio of picture width to height
• IAR = w / h• PAR (pel aspect ratio) =
IAR * vertical_size / horizontal_sizewhere horizontal_size is the width of the image in terms of pels and vertical_size is the height of the image in linesex. Display IAR = 4:3
Image size = 720 pels * 486 linesPAR = 4/3 x 486/720 = 0.9or IAR * display_vertical_size / display_horizontal_size