Chapter 6 : VIDEO

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6.1 Video Concept6.1 Video Concept
• Video is an excellent tool for delivering multimedia.
• Video places the highest performance demand on
computer and its memory and storage.
• Digital video has replaced analog video as the
method of choice for making and delivering video
for multimedia.

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6.1 Video Concept6.1 Video Concept
• Digital video device produces excellent finished products at
a fraction of the cost of analog.
• Digital video eliminates the image-degrading analog-to-
digital conversion.
• Many digital video sources exist, but getting the rights can
be difficult, time-consuming, and expensive.

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6.2 Analogue Video6.2 Analogue Video
• Video information that is stored using television video
signals, film, videotape or other non-computer media
• Each frame is represented by a fluctuating voltage signal
known as an analogue wave form or composite video.

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6.2 Analogue Video6.2 Analogue Video
• Composite analogue video has all the video
components:
– brightness, colour and synchronization
• Then combined into one signal for delivery
• Example : traditional television signal
DIGITAL ANALOGUE

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6.3 Video Display6.3 Video Display
1. Progressive scan :
• used in computer monitors and digital televisions.
• displays all the horizontal lines of a picture at one
time as a single frame.
2. Interlaced scan :
• used in standard television formats
• displays only half of the horizontal lines at a time (the
first field, containing the odd-numbered lines, is
displayed, followed by the second field, containing
the even-numbered lines)

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6.4 Video Signal Broadcast6.4 Video Signal Broadcast

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NTSCNTSC
• National Television Standards Committee
– Standards for coding information into an electronic signal,
to make a TV picture
– US, Japan
• Amplitude modulation
• Frame of video: 525 vertical scan lines
• 30 frames per second
• Two passes drawing (Interlacing)
– Odd-numbered lines
– followed by even-numbered (60 Hz)
– Helps prevent flicker

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PAL, SECAMPAL, SECAM
• PAL: Phase Alternate Line
– Europe, Australia, South Africa
– 625 scan lines
– 25 frames per second
– Odd/even line interlacing
– Amplitude modulation
• SECAM: Sequential Color and Memory
– France, Russia
– Also 625-line, 25 frames per sec, interlaced
– Frequency modulation

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HDTVHDTV
• High Definition Television
– Advanced Television Systems Committee (ATSC,
www.atsc.org)
• Six video formats (resolution & frame rate
combinations)
– 16:9 aspect ratio (width:height ratio)
– 1080 x 1920-pixels or 720 x 1280-pixels
– 24, 30, 60 frames/sec
• MPEG-2 coding for video
• Digital Audio Compression (AC-3) for audio

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6.5 Digitizing Video6.5 Digitizing Video
• Digital video combines features of graphics and audio to
create dynamic content for multimedia products.
• Video is simply moving pictures.
• Digitized video can be edited more easily.
• Digitized video files can be extremely large.

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6.6 Digitizing Video6.6 Digitizing Video
• Digital video is often used to capture content from movies and
television to be used in multimedia.
• A video source (video camera ,VCR, TV or videodisc) is connected to a
video capture card in a computer.
• As the video source is played, the analog signal is sent to the video card
and converted into a digital file (including sound from the video).
VCRVCR
Video Overlay Board /Video Overlay Board /
Video Capture CardVideo Capture Card
PCPC

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Analogue signal from VCR
Converted to DIGITAL
by VIDEO CAPTURE CARD
The converted
signal is
entered inside a
computer
Signal is processed
Video is edited
using video editing
software software

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6.7 Digital Video6.7 Digital Video
• Digital video is the digitisation of analogue video signals into numerical
format
• It creates the illusion of full motion by displaying a rapid sequence of
changing images on a display device.
• Conversion from analogue to digital format requires the use on an ADC
(Analogue to Digital Converter)
• A Digital to Analogue Converter (DAC) can be used to output digital video
on analogue equipment

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Digital VideoDigital Video
• Video clip stored on any mass-storage device can be played back on a
computer’s monitor without special hardware.
• Setting up a production environment for making digital video, requires
some hardware specifications.
• Some specifications include computer with FireWire connection and
cables, fast processor, plenty of RAM, fast and big hard disk.

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6.8 File Size and Formats6.8 File Size and Formats
• There is an important consideration:
– file size in digitized video which included
1. frame rate
2. image size
3. color depth.

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File Size and FormatsFile Size and Formats
1.1. Frame RateFrame Rate
– animation is an illusion caused by the rapid display of
still images.
– television and movies play at 30 fps but acceptable
playback can be achieved with 15 fps.

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2.2. Image SizeImage Size
– A standard full screen resolution is 640x480 pixels but to safe
storing space a video with 320x240 for a computer display is still
acceptable.
– New high-definition televisions (HDTV) are capable of resolutions
up to 1920×1080p60,
• 1920 pixels per scan line by 1080 scan lines, progressive, at 60
frames per second.

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3.3. Color DepthColor Depth
– The quality of video is dependent on the color quality (related to
the number of colors) for each bitmap in the frame sequence.

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3.3. Color DepthColor Depth
– The color depth below 256 colors is poorer-quality image.
– The frame rate to below 15 fps causes a noticeable and
distracting jerkiness that unacceptable.
– Changing the image size and compressing the file therefore become
primary ways of reducing file size.
24 bit 8 bit (256 colors)16 bit

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Video CompressionVideo Compression
• Two types of COMPRESSION:
– Lossless compression.Lossless compression.
• Preserves the exact image throughout the
compression and decompression process.
• E.g: text images is to identify repeating words and
assign them a code.

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Video CompressionVideo Compression
– Lossy compression.Lossy compression.
• Eliminates some of the data in the image and
therefore provides greater compression ratios than
lossless compression.
• Applied to video because some drop in the quality is
not noticeable in moving images.

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Video File FormatsVideo File Formats
• AVI Format (.avi)AVI Format (.avi)
The AVI format, which stands for audio video
interleave, was developed by Microsoft.
The Some of the most common players that
support the avi format aresupport the avi format are:
• Apple QuickTime Player (windows & Mac), Microsoft
Windows Media Player (Windows & Mac), VideoLAN VLC
media player (Windows & Mac) AND Nullsoft Winamp
File FormatsFile Formats

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• Quicktime Format (.mov)
The QuickTime format was developed by Apple
and is a very common one. It is often used on the
internet, and for saving movie and video files.
• The format contains one or more tracks storing
video, audio, text or effects. . It is compatible
with both Mac and Windows platforms, and can
be played on an Apple Quicktime player.

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• MP4 Format (.mp4)
This format is mostly used to store audio and visual streams online,
most commonly those defined by MPEG. It Expands MPEG-1 to
support video/audio "objects", 3D content, low bit rate encoding
and support for Digital Rights Management.
• The MPEG-4 video format uses separate compression for audio and
video tracks; video is compressed with MPEG-4 video encoding;
audio is compressed using AAC compression, the same type of audio
compression used in .AAC files.
• The mp4 can most commonly be played on the Apple QuickTime
Player or other movie players. Devices that play p4 are also known
as mp4 players.

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STREAMING VIDEO
1. Windows Media Video Format (.wmv)
2. 3GP File Extension (.3gp)
3. Apple QuickTime Player
4. RealNetworks RealPlayer
5. VideoLAN VLC media player
6. Advances Streaming Format (.asf)
7. Real Media Format (.rm)

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Video Editing TerminologyVideo Editing Terminology
• LinearLinear
– It plays end to end in one direction, usually
pertains to videotape editing specifically the
editing of linear tape segments into one final
master tape.

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6.9 Video Editing Terminology6.9 Video Editing Terminology
• Linear VS Non-linearLinear VS Non-linear
– Refers to the editing of disk-based digital video.
– The software provides an on screen map of what the final
video sequences should look like incorporating the edits,
splices, special effects, transitions and sound tracks.

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Special EffectsSpecial Effects
• TransitionsTransitions
– Such as fading, wiping, splatters, scrolling, stipple and
many more are available by simply dragging and dropping
that transition between the two video clips.

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• CHROMA KEYCHROMA KEY
– The ability to superimpose one clip over another is a
valuable technique.
– The technique of green screening is identical except
that the color green is used for the screen and later
digitally removed.
– The blue screen and green screen superimposing are
just two of the superimposing technique available.

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Video Hardware and SoftwareVideo Hardware and Software
VCRVCR
Video Overlay Board /Video Overlay Board /
Video Capture CardVideo Capture Card
Video digitalVideo digital
Editing SoftwareEditing Software
MULTIMEDIA PCMULTIMEDIA PC

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Video Editing SoftwareVideo Editing Software
• Incorporating transitions such as dissolves, wipes and spin.
• Superimposing titles and animating them, such as fly-in
logo.
• Applying special effects to various images, such as twisting,
zooming, rotating and distorting.
• Synchronizing sound with the video.
• Apply filters that control color balance, brightness &
contrast, blurring, distortions and morphing.

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Obtaining Video ClipsObtaining Video Clips
• Shoot a new footage
• Pre existing video clips
• Buying from others (licensing rights)

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Shooting and Editing VideoShooting and Editing Video
• Equipment needed :
1) Good camera
2) Lighting equipment
3) Powerful PC :

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Advantages of using VideoAdvantages of using Video
• Captures interest
• Increase retention
• Clarifies complex physical actions and
relationships
• Can incorporate other media

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6.10 Disadvantages of using Video6.10 Disadvantages of using Video
• Is expensive to produce
• Requires extensive memory and storage
• Requires special equipment
• Does not effectively illustrate abstract
concepts and static situations

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SummarySummary
• Digital video method is used for making and
delivering video for multimedia.
• Compression techniques help to reduce the
file sizes to more manageable levels
• 2 types of compression lossless and lossy.
• Standards for compression program are JPEG
and MPEG.

Chapter 6 : VIDEO

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