Video
Video
Video
MMM1023
TOPIC OUTLINE
What is digital video.
How digital video is process and stored.
Blu-ray (BD)
Refer to blue laser used to read the disc
Can hold up to 128GB on quadruple layer
ANALOG VIDEO
An electrical signal, visual information is
recorded by changes in signal amplitude.
Stored using television signals, film,
videotape or others non-computer media.
It is important because it defines where
the digital content will come from and
what will be required for the computer to
access it.
To appreciate the capabilities of digital
video.
How Video Works (continued)
• Analog video
– Video is recorded onto magnetic tapes.
– Video frames are interlaced.
TYPE OF ANALOG VIDEO
In an analog video signal, each frame of
the video is represented by a fluctuating
voltage signal known as an analog wave
form refer to as composite video.
It contain brightness, color and (sync)
synchronization combined into 1 signal.
Compositing results in color bleeding, low
clarity and high generational loss.
ANALOG VIDEO REPRESENTATION
Frame Rate:
Number of frames per second produced
by a video signal
Common rates are 25-75KHz (fps).
Low frame rates flicker and motion blurs
and is jerky.
ANALOG VIDEO REPRESENTATION
Number of Scan Line
Video format divide frames into scan
lines each frame has the same number
of scan lines.
Video scan rate is the number of lines
scanned per second ( frame rate X scan
line per frame)
Aspect ratio :
- Ratio of width of video image to
height, current broadcast format are 4:3
ANALOG VIDEO REPRESENTATION
Interlacing :
Low frame rates produce flicker.
Flicker can be reduce by interlacing,
frames are divided into 2 fields, 1
contain odd number scan line and other
the even.
During display entire 1st field is drawn
then entire 2nd field, result : display
appears to refresh at twice the original
frame rate.
Form interlacing 2:1.
COMPOSITE/ANALOG VIDEO
FORMAT FOR TV
NTSC (National Television Standard
Committee).
PAL (Phase Alternate Line)
SECAM (Sequential Color with Memory –
Sequential Couleur avec Memoire).
HDTV.
NTSC (NATIONAL TELEVISION
STANDARD COMMITTEE).
Used in USA and Japan for transmission
video.
Known also as Never The Same Color.
Computer storage
(hard disk)
COMPUTER BASED DIGITAL
VIDEO-CONT
Video capture board is able to
accept and convert analog video to
digital at 1 to 24 bit quality up to
30 frames per second.
Compression hardware or circuitry
on video capture boards that
compress digital video in real time.
CHARACTERISTICS OF
DIGITAL VIDEO
A frame is a single image in a video
sequence and is the same as single
cell of movie film.
3 basic characteristics:
Frame Rate:
Number of images displayed within a
specified amount of time to convey a sense of
motion.
CHARACTERISTICS OF DIGITAL
VIDEO-CONT
Frame Size:
The height and width of each
individual frame or image.
Color Depth or Resolution:
The amount of color for each
pixel within each frame or image.
Characteristics of digital video
Frame Size : height
and width of a frame
(measured in pixels)
Video Frame
1
Video Frame
2 … Video Frame
3
Interlaced
scanning for
NTSC video
signals.
COMPUTER FRAME DISPLAY
Computer monitor uses process called
progressive scan to update the computer
display one line at a time from top to
bottom.
It’s not broken into field like TV.
Entire frame display 30 times every
second and is refer to non-interlaced
video.
FRAME SIZE
NTSC and PAL standards have larger
image than standard desktop computer
video frame size.
VGA (video graphic adapter) standard
used in monitor with resolution of 640 X
480 pixels.
Different in resolution often result in
downsizing of the video, loss in image.
COLOR DEPTH
Refer to the number of colors displayed
on the screen at one time.
Computer deal with RGB color (Red-
green-Blue) format.
It’s ranging from 1 bit-2 color, 8bits-256
color,16 bit-65,535 color and 24 bit-
16.7million color).
COLOR DEPTH-CONT
In digital video, use 2 color strategies:
24 bit color to achieve optimal color
reproduction.
8-bit black and white (grayscale) or 256 color
for a reduction in file size, while maintain the
image resolution.
24 bit often used because it enables digital
video to be transport across platform with
minimal loss per frame image quality.
While 8 bit color, have smaller data sets
suitable for transmission on the internet.
QUALITY
Related to factors include frame size,
frame rate, color depth and quantity of
video (number of seconds or minutes of
video).
Some require ¼ screen, 15 frame per
second video, at 8-bit per pixel,
Other require full screen (640 by480), full
frame rate video(24 or 30 frame per
second) at 24 bits per pixel (16.7 million
colors).
QUALITY-CONT
Also depend on content;
Video with great deal motion require higher
frame rate to achieve an acceptable level of
quality for playback.
Video of great outdoor (scenery) require a
larger frame size and 24 bit color to adequately
present desired effect.
Need to understand how to size digital
video in order to provide the best quality
when producing digital video.
VIDEO COMPRESSION
It used mathematical algorithms and
required to manageable for storage,
transport and processing.
Based on applying an algorithm to the
raw video stream to reduce data size and
it will determine how data is compress in
playback and capture process.
Codecs is a driver compress the video file
into small, compact and highly usable file
sizes, reduce file sizes.
COMPRESSION RATIOS
Relates to a numerical representation of
the original video in comparison to the
compressed video.
200:1, compression ratio means original
video is represented by 200 and compress
video is represented by 1.
Higher the compression, poorer the video
quality.
LOSSY VS LOSSLESS
COMPRESSION
Known as spatial and temporal
compression.
Spatial compression; A digital
compression of video data that compresses
the size of the video file by compressing
the image data of each frame.
It make each frame image smaller and
result in lossy compression (loses image
definition).
LOSSY VS LOSSLESS
COMPRESSION
Temporal compression; A digital
compression of video data that uses
similarities of sequential frames over time
to determine and store only the image
data that differs from frame to frame.
Known as frame differencing (lossless)
uses similarities of individual frames over
time to remove repetitive data. Only
changes between sequential frames are
stored.
REALTIME VS NONREAL
TIME VIDEO
Means video compression system
must capture, compress to disk,
decompress and playback video
at the capture frame rate in real
time with no delays.
SYMMETRICAL VS
ASYMMETRICAL COMPRESSION
Referto how video images are compressed
and decompressed (real-time
compression).
Symmetrical compression means, a
playback sequence of 640 X480 video at 30
frames per second, which capture,
compress and store process in 30 seconds.
SYMMETRICAL VS
ASYMMETRICAL COMPRESSION
Asymmetrical compression means
opposite. Degree of asymmetry expressed
in ratio of 150:1, which takes 150 minutes
to compress 1 minute of video.
It’s more elaborate and efficient for
quality and speed at playback because it
uses more time to compress the video
INTERFRAME VS INTRAFRAME
COMPRESSION
Intraframe (relative); compress and stores
each video frame as a discrete picture. Ex;
MPEG
Interframe (absolute) : based on although
action is happening, the background in
most video scenes remain stables. Ex;
JPEG.
VIDEO CAPTURE SYSTEM
Video capture system consist:
Video Source (VCR):, capable of producing
NTSC, PAL or others compatible video signal.
ADC: for converting analog video to digital.
Audio Capture Circuitry: sound capture
device operates together with video capture
system.
Hardware Compression Chip: special h/w
for implementing a compression algorithm on
the raw video stream.
Video Capture with Hardware
(Symmetric Compression)
Analog to Data
Video In digital Storage
converter (video may
Video
Source be
compressed
Audio In Audio
Capture
later)
Circuitry
VIDEO PLAYBACK SYSTEM
Video playback in 2 ways:
Video data is decompressed and
processed into images that are
displayed by the computer video
graphics system.
- Processing will be completed by processor.
Video data is decompressed by
additional hardware called
‘decompressor’. Video info is transfer
directly to the video graphics system.
- Processor only responsible for managing
file access and related system function.
Video Playback via Computer Processor
Video
Video Out graphic
adapter
Computer Data
Processor Storage
Audio Out Audio
Playback
Circuitry
Video Playback via the Supporting
Hardware
Video
Video Out graphic Video
adapter Decompressor
Data
Audio Computer
Storage
Audio Out
Playback Processor
Circuitry
DIGITAL VIDEO SOFTWARE
Based on 2 approach:
1. Each application that depends on
digital video is responsible for all
aspects of controlling video capture
hardware, compression and playback.
2. S/w drivers within the OS control
video capture, compression and
playback.
DIGITAL VIDEO SOFTWARE
Come in 3 basic o Video Capture :
forms: - Used to control video
1. Video capture. capture h/w.
- Include ability to
2. Video editing. control video signal
3. Video playback input; color and
brightness.
applications.
- Control compression
selection , algorithm,
frame rate, frame size,
color depth, bit rate and
audio sampling.
DIGITAL VIDEO SOFTWARE
Video Editing :
Compressing raw digital video to smaller
files.
Copy, cut, paste and delete video frames.
Combine frames from 2 or more video data
sources.
Changing size or frame rate of the video
data segments.
Editing audio by remove, copy or adding.
Adding special effect to video clips such as
titles or transitions between video segments.
DIGITAL VIDEO SOFTWARE
Video Playback:
Play the video within a window
or full screen application with
controls to play, pause, stop,
rewind, fast forward and frame
advance or retreat.
User can jump around the video
by pointing to certain location of
the frame video.
VIDEO EDITING TECHNIQUE
LINEAR:
Videotape editing.
Play from begin to end in 1
direction.
NONLINEAR:
Editing of disk-based digital
video.
Provides onscreen map of what
final video sequences look like.
Incorporating the edits, splices,
special effect, transitions and
sound tracks.
NONLINEAR EDITING
NONLINEAR EDITING
SPECIAL EFFECT
Transition:
Such as fading, wiping, splatters,
scrolling, stipple, fade-in and etc.
Superimposing:
Add features, image or background to
the screen.
Filters:
To create lens flares, pointilize,
emboss, zoom, pan, twist and etc.
Used to change duration of the video.
MORPHING
Shooting and Editing Video
Shooting and Editing Video
• Lighting
– Always strive for adequate lighting.
Shooting and Editing Video
• Chroma keys
– Blue screen or chroma key editing is used to
superimpose subjects over different
backgrounds.
MORPHING
A digital process where 1 image
crossfade into another with a twist.
Ex; running tiger change into a sport car
or human change to aliens.
(read the details in the multimedia,
concept and practice).
SOFTWARE FOR VIDEO
EDITING
Gold Disk’s Astound Studio
Adobe Premiere
Adobe After Effects
FORMAT FILE
AVI (.avi)
Audio Video Interleave Format.
Support on all windows platforms.
Not supported by Macintosh unless
they install the software from
Microsoft.
Use in windows media player.
FORMAT FILE
QuickTime (.mov)
Support on Windows and
Macintosh platforms.
Need to install the Apple’s
QuickTime player software .
Versatile format widely used to
distribute video over the web.
FORMAT FILE
MPEG (Motion Picture Expert
Group)
MPEG-1 : 1.2 Mbps of video and
250Kbps of 2 channels stereo audio
using CD-ROM.
MPEG-2 : broadcast quality video
at rates between 3-15 Mbps.
MPEG-4 : low data rate video, can
view 3D and VR applications.
MPEG-7 : metadata standard for
video presentation.
http://www.mpeg.org
FORMAT FILE
Microsoft Video 1
Support 8 bit and 24 bit color
palettes.
Small compress file.
Microsoft RLE
Best for compressing comp
generated image and animation.
Only available in AVI, support 8
bit color.
FORMAT FILE
Cinepak
For AVI and QuickTime format.
High compression and good fidelity.
Using asymmetrical compression.
Indeo
Intel Indeo codec available for AVI and
QuickTime.
Additional features ; Indeo
Interactivity, scalability the quality.
FORMAT FILE
Sorensen
Only for QuickTime version 3 or higher.
Provide better quality and compression
rate.
Web-specific
Need to have plug-in installed in the
browser.
CODECS
Thealgorithm used to compress (code) a
video for delivery.
Decodes the compressed video in real-time
for fast playback.
Streaming audio and video starts
playback as soon as enough data has
transferred to the user’s computer to
sustain this playback.
CODECS AND FILE
EXTENSIONS
CODECS FILE EXTENSION
Cinepax .avi
Indeo .avi
MPEG .mpg
USING VIDEO
Used it for information delivery and
present complex information.
Careful when purchasing the s/w
Choose most appropriate video file.
Not too much transition and special effect
cause delay in rendering process.
Try to have smaller file.
If the capturing and editing software is
different, make sure to set it to standard
format so it can be used in both process.
CONCLUSION
What is the different between Analog and
digital Video
Name type of video compression?