1. Chapter 5:- Video
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2. Topics: Introduction to Video Advantages of Digital Video
Video File Format
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3. Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.
Video makes use of all of the elements of multimedia, bringing your products and services alive, but at a high cost.
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4. Video
The advantage of integrating video into a multimedia presentation is the capacity to effectively convey a great deal of information in the least amount of time.
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5. General Information
Originally video material was processed using analog tools
Nowadays it is common, that digital processing is used in
recording
editing
broadcasting
video material is widely used within multimedia production
With higher bandwidths the Internet has become a common way of video transfers / broadcasting
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6. General Information The most recent uses of digital video are e.g.
DVD/BlueRay
Digital TV-Broadcasting
Mobile Devices used for playing video material
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7. Video
Video is also very hardware-intensive (require the highest performance demand on your computer)
Storage issue: full-screen, uncompressed video uses over 20 megabytes per second (MBps) of bandwidth and storage space.
Processor capability in handling very huge data on real time delivery
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8. Uses of Video in Multimedia
Video enhances common applications of multimedia.
Video simulations show procedures and interactions that would be dangerous to perform in actuality
Games use video to simulate flight, car racing, and other action
Web sites and CD-ROMs use videos as reference material
Videoconferences enable participants to see each other and witness demonstrations
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9. Digitizing the Video Signal
Analogue video is essentially a product of the television industry and therefore conforms to television standards.
Digital video is a product of the computing industry and therefore conforms to digital data standards.
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10. Analogue video
Analog video is a video signal transferred by an analog signal.
An analog color video signal contains luminance, brightness (Y) and chrominance (C) of an analog television image.
When combined into one channel, it is called composite video as is the case, among others with NTSC, PAL and SECAM.
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11. Composite Video
A video signal that combines the (brightness), (color), (color reference), and sync (horizontal and vertical synchronizing signals) into a single waveform carried on a single wire pair.
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12. 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.
Composite analogue video has all the video components: brightness, color and synchronization
Then, combined into one signal for delivery
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13. Analogue video Usage : television Problems: color blending low clarity
high generation lost
difficult to edit
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14. Type of Analogue Video Signal
There are two main analogue video formats
PAL and NTSC
SECAM
PAL (Phase Alternate Line)
standard television format used in the European, UK, Australia and South Africa
Consist 625 scan lines drawn every 1/25 second
video(768 x 576 and 25 fps)
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15. Type of Analogue Video Signal
NTSC  (National Television Systems Committeeis ) the American and Japanese standard
Consist of 525 scan lines drawn every 1/30 second
(640 x 480 and fps)
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16. Aspect Ratio
The ratio of the visible-picture width to the height. Standard television and computers have an aspect ratio of 4:3(1.33). HDTV has aspects ratios of either 4:3 or 16:9(1.78). Additional aspect ratios like 1.85:1 or 2.35:1 are used in cinema.
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17. Digitizing the Video Signal
Is usually recorded and played as an analog signal.
It must therefore be digitized in order to be incorporated into a multimedia title.
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18. 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.

19. 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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21. Advantages of Digital Video
One of the advantages of digitized video is that it can be easily edited. (noise removal, cut and paste, etc.),
The video is stored as a standard computer file.
Software motion video does not require specialized hardware for playback.
Digital video requires neither a video board in the computer nor an external device (which adds extra costs and complexity) such as a videodisc player.
Long-lasting.
Direct access is possible, which makes nonlinear video editing achievable as a simple, rather than a complex, task;
Repeated recording does not degrade image quality;
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22. Disadvantages of Digital Video
Requires large storage capacity devices.
Copies can be made illegally.
Need fast computer system for playback and capture.
Requires knowledge of digital compression technology.
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23. File Size Considerations
Digitized video files can be extremely large.
A single second of high-quality color video that takes up only one-quarter of a computer screen can be as large as 1 MB.
Several elements determine the file size:
–Frame Rate
–Image Size
–Color Depth
–the length of the video
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24. 1- Frame rate
Number of images displayed within a specified amount of time to convey a sense of motion
Usually measured in frames per second
Standard video movie is 30 fps, movie film is 24 fps
Video digital is at least 15 fps
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25. File Size and Formats
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.

26. 2- Image size the width and height of each individual frame or image
Determines the quality of the image displayed and the processing involved to display that image
Standard full screen resolution is 640x480 pixels
Video screen display is one fourth the size of the full window screen (320x240)
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27. 2- Image 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.

28. 3- Colour depth/Resolution
Number of colors displayed on the screen at one time
Ranging from 1 bit to 8 bit, 16 or 24 bit per pixel
Quality directly related to frame size, image size and color depth.
Quality also depends on content. Motion picture needs higher frame rate
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29. 3- Colour depth/Resolution
The quality of video is dependent on the color quality (related to the number of colors) for each bitmap in the frame sequence.

30. This does not include any sound data !
4- Time
File size = frame size * frame rate * Color Depth * time
Where:
Frame size = image size ( width * height in pixels)
Frame rate = frames per second
Color depth = measured in bytes
time = time in seconds
This does not include any sound data !
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31. Video Editing Terminology
Linear
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.

32. Video Editing Terminology
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.

33. Video Compression
Because of the large sizes associated with video files, video compression/decompression programs, known as codecs, have been developed.
These programs can substantially reduce the size of video files, which means that more video can fit on a single CD and that the speed of transferring video from a CD to the computer can be increased.
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34. Compression techniques
Since the size of raw digital video is so large we need some means to compress the information
Video compression and decompression program, known as Codecs
Lossy compression techniques cause some information to be lost from the original image
Redundant information
Example: Image and video
JPEG and MPEG
Intraframe and Interframe
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35. Compression techniques
Lossless compression techniques do not lose information throughout the compression and decompression process
Example use in text images
Exactly same before and after compression
Technique is identify repeating words and assign them a code.
Decompression, the code would be changed back to the actual word.
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36. Video File Format A video file’s format determines:
Which programs can open and play it.
How much space it occupies on a disk.
How fast it travels over an Internet connection.
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37. Calculate Video File Size
Size = Frame size x Frame rate x color depth x duration
Notes (Color depth) : B&W video = 1 byte
Color video = 3 bytes
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38. Calculate Video File Size
Example 1:
Calculate the file size for a video with 320 x 240 pixels, color video, 30 fps, and length 15 seconds.
Video file size = 320 x 240 x 3 x 30 x 15
= bytes
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39. Calculate Video File Size
Example 2:
Calculate the file size for a video with 300 x 200 pixels, black and white video, 25 fps, and length 30 seconds.
Video file size = 300 x 200 x 1 x 25 x 30
= bytes
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40. Guidelines
Reducing the color depth to less than 256 colors gives a markedly poorer-quality image.
In most multimedia titles, you do not need to show full-screen video.
Reducing file size to minimize the use of video in the image that appears on the screen.
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41. Digital Video File Formats
Audio Video Interleaved(.avi)
Windows Media Video (.wmv)
Motion Pictures Expert Group (.mpg)
Adobe Flash video (.flv)
(Apple QuickTime Movie) (.mov)
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42. What is a container??
A container is a collection of files that stores information about the digital file.
it consists of the video and audio codecs along with other information, such as subtitles and chapters. You have control over the type of codec you wish to choose for audio and video separately.
The popular types of containers are AVI, MP4 and MOV.
A new open source container that's gaining popularity recentlMKV,y is the reason being that it can support nearly any video codec known.
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43. . AVI (Audio Video Interlaced)
Developed by Microsoft and introduced in 1992 as part of its Video for Windows technology.
An uncompressed .AVI file is too huge and will be difficult to be transferred over the Internet.
AVI files are able to run on a number of different systems like Windows, Macintosh, Linux.
Also supported by popular web browsers.   
AVI files stores data that can be encoded in a number of different codec’s.
.AVI files are mainly used for editing, as they are compatible with almost any application.
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44. Microsoft AVI Audio Video Interleave format
Interleaving is a technique used to embed two or more things into the same stream of information
In every chunk of information you will find some video data and some audio data
...
8, 16 or 24 bits
Video
information
Audio
information

45. .WMV (Windows Media Video)
Developed by Microsoft.
WMV was originally designed for web streaming applications, as a competitor to RealVideo, but it can now cater to more specialized content. 
their file size decreases significantly after compression, which results in poor video quality.
the Windows Media Player is the main application that is used to play WMV files on all Microsoft’s Windows operating systems.
.WMV files are used for streaming as well as downloading content over the Internet.
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46. MPEG-4 (.MP4)
MP4 is a video format mainly used by camcorders and cameras that is gaining popularity.
The quality of a video coded using .MP4 is very high and the file size relatively small.
.MP4 standard is becoming more popular than .FLV for online video sharing, as it compatible with both online and mobile browsers and also supported by the new HTML5.
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47. Video File Formats MPEG A standard covering video & audio
Most commonly used layers are MPEG-1, MPEG-2 and MPEG-4
File extensions .mpeg and .mpg
First introduced in 1998.
he MPEG-4 video format uses separate compression for audio and video tracks.
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48. MPEG video
The Motion Picture Experts Group is an international group that was created to develop standards for audio and video file formats.
There are a number of MPEG formats:
MPEG-1 is a format used for low quality video (generally displayed on computers)
MPEG-2 is used for digital TV broadcasts and DVDs
MPEG-1 Layer 3 is the popular encoding mechanism for MP3 audio files (more on this later in this course)
MPEG-4 is a new format for multimedia presentations
Can require separate hardware to decode higher quality MPEG video data
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49. MPEG compression example
A simple scene showing a car moving across a desert landscape
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Only the difference between the current and next frame needs to be stored
This is called intraframe coding

50. .FLV (Flash Video Format)
FLV files are videos that are encoded by Adobe Flash software.
A Flash video file format is the most common and popular video sharing file format used over the Internet.
Almost all browsers are compatible with Flash and can the play the video with ease.
Most online video games are also done in a Flash video format.
Many video-sharing sites will let you upload a video in a different format, after which they will convert the files to .FLV on the fly.
An example of such a site is YouTube.
Videos in the .FLV format are high quality even after compression, and that is one of the major reasons for the popularity of .FLV.
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51. MOV (Apple QuickTime Movie)
Developed by Apple.
The QuickTime file format is a popular type of video sharing and viewing format amongst Macintosh users.
Often used on the Web, and for saving movie and video files.
. MOV files are most commonly opened via the Apple QuickTime Player for the Macintosh Operating System.
there is a free version of the QuickTime Player available for the Windows Operating System among many other players.
Considered one of the best looking file formats, MOV files are of high quality and are usually big in file size.
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52. MKV
MKV is a flexible, open standard video file format that has quickly become the preferred file extension for high definition video on the Internet.
The MKV container can include video, audio, and features such as alternate audio tracks, multilingual subtitles and chapter points, as well as rich metadata including cover art, ratings, descriptions and more.
MKV offers a richer media experience than any other current format, and that’s why we chose it as the file container for DivX Plus video.
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53. What is DivX?
DivX® is the name of a popular new video compression technology developed by DivX .Inc.
The format was developed to enable users to play and create high- quality videos in a fast and convenient way, while still maintaining the best quality possible.
The DivX® codec is currently the most popular MPEG-4 based codec because of its quality, speed and efficiency as well as the wide range of DVD players that support the DivX® format. 
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54. Software Environment For viewing a video file a player is needed, e.g.
Media Player
Quicktime Player
RealPlayer
There are often major differencies between the release versions of players
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55. Software Environment
For editing of video a dedicated piece of software is needed e.g.
Adobe Premiere
Avid
Final Cut Pro
WinXP includes a Movie Maker –tool which is capable of basic video editing
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56. What is streaming video?
Streaming video refers to a technique for transferring data so that the browser starts displaying the data before the entire file has been transmitted.
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57. What is HD?
HD, or High Definition, refers to the detail level of a screen; or to put it another way, the number of pixels that are packed into a display.
Officially it is video with a resolution of 1280×720 (720p) or 1920×1080 (1080i or 1080p). All of the formats are widescreen 16:9 and display between 24 and 60 frames per second.
The scanning is either progressive (every frame the entire picture is drawn) or interlace (only for 1080 where every other frame has half the lines redrawn).
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58. What is HD?
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59. What is HD? What is 1080i and how is that different to 1080p?
1080i and 1080p broadcasts both display images at the same pixel count as each other x The big difference is in how images are made up on your TV.
The lowercase ‘i’ in 1080i stands for interlaced scan. The lowercase ‘p’ in 1080p stands for progressive scan.
Interlaced scan renders images in vertical lines, breaking down the picture into individual columns and then displaying every other line at a very high rate - at 1/25th of a second. Odd-numbered lines get painted on the screen first, then even numbered lines. While this is incredibly fast and impossible for the human eye to detect, it can create a ghostly flickering effect on live TV broadcasts, particularly live sporting events.   
Progressive scan renders images sequentially, all at once. This makes for a much smoother image overall that doesn’t suffer from this ghosting effect.
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60. Lab Exercise: 1.Using online wave editor:
2.Using online video editor:
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