Video Element Les 5 Flashcards
___ is the element of
multimedia that can hold the
interest of viewers in a
presentation
Motion video
The visual effect of motion is due to a biological phenomenon known as ___
persistence of vision
An object seen by the human eye remains mapped on the eye’s retina for a
brief time after viewing (approximately ___ms)
25
Another phenomenon contributing to the vision of motion is known as ___
phi phenomenon
____ To represent
visual reality, two conditions must be met
* the rate of repetition of the images must be high
enough to guarantee smooth motion from frame to frame
* the rate must be high enough so that the persistence
of vision extends over the interval between flashes
Temporal aspect of Illumination
The frequency at which the flicking light source
must be repeated before it appears continuous is
known as the ___
fusion frequency
It is known that we perceive a continuous motion to
happen at any frame rate faster than 15 frames per
second
Visual Representation
A technique known as ___improves the
view by
* dividing a frame into two fields, each
contains the alternative scan lines, and
* displaying the field in twice of the frames rate
interleaving
Three main conventional broadcast television systems
- NSTC(National Television Systems Committee
- SECAM (Sequential Couleur Avec Memoire
- PAL (Phase Alternating Line)
developed in the U.S. and used in North and South
America, Japan
* A picture consists of 525 lines and frame rate is
approximately 30Hz
- NSTC(National Television Systems Committee
___) is a
standard used in France and Eastern Europe
* A picture consists of 625 lines and frame rate is
25Hz
SECAM(SEquential Couleur Avec Memoire
___ is used in most part of
western Europe, most part of Asia (including China
and HongKong) andother countries
PAL (Phase Alternating Line)
The smallest detail that can be reproduced in the
image is a ___
pixel
Conventional video systems have relative ____ compare to computer screens: typical resolution of 640 x 480, even up to 1024 x 768
low resolution
____ to select/combine video sources, to convert analog video signal to digital samples
Video input mixer and ADC
__- temporary storage for video frame
Video frame buffer
___ to filter or enhance the video frame, e.g., reduce noise, adjust brightness, contrast and color
Video processor
___ to compress and encode the digital video into a required format
Compressor/encoder
___to the system PCI bus
Interface
____ format was defined by Microsoft for its Video for
Windows systems
* It supports video playback at up to 30 frames per second on a small window (typical size 300 x 200 with 8 or 16 bit color)
* It is a software-only system
* It supports a number of compression algorithms
AVI (Audio Video Interleaved)
____ was originally developed by Apple for storing audio and video in Macintosh systems
* It supports video playback at up to 30 frames per second on a small window
(typical size 300 x 200 with 8 or 16 bit color)
* It is a software-only system
* It supports a number of compression algorithms
QuickTime
___ is a working group under ISO
* There are several versions of mpeg standard. The most commonly used now is
mpeg-1
* It requires hardware support for encoding and decoding (on slow systems)
* The maximumdatarateis 1.5Megabit/sec
* The next generation mpeg-2 is now getting popular
* Mpeg-2improves mpeg-1 by increasing the maximum data rate to 15Mbit/sec
* It can interleave audio and video
MPEG(Motion Picture Expect Group)
