Video Digital Video is composed of a series of bitmap graphics,

each one called a frame Powerful communication media: video with sound more

convincing than a scrolling text filed with the same speech.

Before you decide to add video to your project it is important to have understanding of the medium, its limitation and cost.

The cost of videoFilming costsProcessing / editing costsData budget costsCognitive costs

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Digital or analogue Professional digital equipment is no

longer expensive.

Digital filming is becoming common for low budget and multimedia projects.

Digital camcorder directly connected to computer brings the power of video editing to every day users.

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The Video Process When light reflected from an object passes through a

video camera, that light is converted to an electronic signal by one or more Charge Coupled Devices (CCD).

CCD output is processed, by camera, into RGB signals, and combined with a synchronization pulse.

Types of video signal– RGB preferred: three separate signals, one for each of R,

G, & B.– Component Video: two separate signals one for

chroma (color information) and one for brightness.– Composite Video - single signal containing all

information.

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Analogue Video

Video signal (RGB, Component or Composite) is written to magnetic tape.

Audio track at top of tape (one or two channels).

Video track in the middle of the tape.

Control track at bottom of tape - containssynchronization pulses.

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Broadcast Standards

NTSC PAL SECAM HDTV

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NTSC Standard National Television Standards Committee

(1952) US & Far East A single frame of video is made up of 525

scan lines 30 frames per second (each frame takes

1/30 of a second Interlaced: lines are drawn in two passes

(odd/even) each at rate of 60Hz

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PAL Standard

Phase Alternate Line (PAL) is an integrated method of adding color to B&W television signal.

UK, most of Europe, Australia & South Africa

625 scan lines 25 frames per second Interlaced at 50Hz

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SECAM Standard

Sequential Color and Memory France & Russia 625 scan lines (as PAL) 25 frames per second (as PAL) Interlaced at 50Hz (as PAL) Color model completely different from

PAL

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HDTV (High Definition Television)

Six separate HDTV “standards” in twocategories:

1920x1080 at (24, 30, and 60 fps). Interlaced & most favored by broadcasting industry

1280x720 progressive-scan at 24, 30, and 60 fps

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Conversion between analogue formats

PAL / SECAM conversion is fairly easy(i.e. cheap)

PAL & SECAM / NTSC conversion is much more complex (i.e. expensive)

Low quality conversion is now cheap& dual standard equipment exists

High quality conversion remains expensive

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Why HDTV?

Higher-resolution picture Wider picture Digital surround sound. Additional data Easy to interface with computers

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Video Color Models Computers use RGB component video and their

colors are purer and more accurate than those seen on TV.

NTSC, PAL & SECAM use different colors models and limited palette. Thus graphic images created on computers may display differently when transformed into any of the TV systems.

Not all RGB colors are available on conventional TV sets.

So if the MM project is to be delivered to playstation, it may not play back. In this case use colors to meet NTSC color.

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Digital Video Source

Film as digital video using FireWire standard cable.

Film as analogue and then digitized it. To accomplish that a video capturing board is needed. – Wildly variable in price and quality

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What kinds of Digital Videos?

Classified by its platform or application (how it will be delivered)

1. Desktop video (DTV)

• Videos constructed and displayed using a personal computer

2. Web-based video

• Incorporated in Web pages and accessed with a browser

3. DVD-video

• A DVD format used for commercial DVDs that contain feature-length films.

4. PDA video

• Small-format video designed to be viewed on a PDA or cell phone screen

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Digital Video Playback Playback Software Microsoft Video for Windows

– Framework for video playback– Audio Video Interleave (AVI)

Apple Quicktime– Framework for all time-based media– Movie files (MOV)– Bundled with MacOS– Quicktime for Windows

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Video Compression I Video compression is always lossy. Multi-way trade-off– File size / transfer rate (bandwidth)– Frame rate (typically 15fps for multimedia)– Image quality– Frame size Different codecs have differing strengths

and weaknesses.

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discards “repetitive” or “redundant” data; may not be noticeable to the eye

results in a compression ratio as large as 200:1 in some cases

Greater ratio, poorer the decompressed image applied to video because quality loss not

noticeable in moving images Applied to Internet streaming Applied to .jpg and .mpeg formats

Video Compression II

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Spatial Compression vs. Temporal Compression

Spatial Compress each frame individually Uses the same techniques as JPG compression Codecs that do spatial compression are: Animation,

PlanarRGB Temporal

Just save info on selected frames (called keyframes) All other frames just save the differences from the

previous keyframe Good when the difference between current frame and

keyframe is small

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Compression Codecs Framework (V4W or Quicktime) does not

contain compression software.

Compression software using a specific algorithm is called a codec (coder/decoder).

Examples of Codecs: Indeo MPEG

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Indeo

Algorithms developed for DVI - Intel i750 chipset

Indeo - implemented in software Two levels of compression

– PLV (Production Level Video)– RTV (Real Time Video)

Typical compression ratio of 160:1

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MPEG Moving Picture Expert Group Established by ISO in 1988 Defined standards are used in– Digital television– Video phones– Consumer electronics– Digital cinema– Video games

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MPEG1 The original MPEG standard Objective - deliver video and audio from CD-ROM with

comparable quality to VHS tape and CD audio. Encodes an audiovisual signal in about 1.5 Mbps Images are progressively scanned

Standard is in five parts– 1. Systems– 2. Video– 3. Audio– 4. Conformance testing– 5. C implementation (encoding and decoding)

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Applications of MPEG 1

Consumer Devices Multimedia / CD ROM Internet Video.

Compression is cheap

Video CD - production is extremely cheap

Audio only devices (MP3 players) Internet audio

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MPEG 2 Dates from 1990, a completely different standard from

MPEG 1. Objective - deliver video and audio at comparable

quality to broadcast composite video at roughly 4 times the typical MPEG 1 bit rate.

Improvements over MPEG 1– Higher resolution– Higher image quality– Supports interlaced video formats– Multiresolution scalability– Multiple sound track features

Encryption and metadata capabilities

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Applications of MPEG 2

Digital Satellite TV Digital Cable TV DVD Some multimedia (usually where very

high quality is essential)

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MPEG 4

MPEG 4 is capable of encoding digital video objects of any shape Thus the screen can consist of many

different video objects. For example different “people” can stay

together around a table 2D images can be represented in 3D space.

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MPEG 4 MPEG 4 has the following capabilities:

Encode natural or synthetic images. Real-time or non real-time. Streams from different sources can be combined Contains the possibility of interaction with

objects. Hyperlinking, and uploading and downloading of

data Readily adjusts delivery to available bandwidth Microsoft and Apple are implementing it in their

core technologies (ie Windows media services and Quicktime)

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MPEG-7 Multimedia content description interface Aimed at addressing issues of content retrieval

Intended primarily for digital libraries Object based (as MPEG-4) Supported data:

Still images 3D models Sampled audio Speech Video Composition information (combinations of the above)

Data representation Binary objects, XML or both

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MPEG-21 Designed to manage digital media

resources Digital item declaration Digital item identification and description Content management and usage Intellectual property management and

protection Terminals and networks Content representation Event reporting

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Creating Digital Video

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Ready to Make a Video I

1. Pre-Production Stage: Planning the video and gathering any resources you

might need Length of final video Music or sounds, script or storyboard

http://www.youtube.com/watch?v=t3mAHQuBqQI Camcorder type and medium and format of final

video

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2. Production Stage: Camera work and sound recording The potential for a good shot is better if you understand

how to use the technical controls on your camera, i.e. resolution, capturing action shots vs. stills, night time vs. daytime shots. All of these shots require certain settings on your camera to get the best quality.

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Ready to Make a Video II

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3. Post-Production: Downloading from camcorder to computer Editing and/or encoding the finished video. Removing unwanted footage Arranging desired footage in the correct order Adding music, titles, transitions and possibly

other effects Converting (encoding) into the correct

format(s)

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Ready to Make a Video III

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Assumption that you have caught your video on a camcorder

Post-Production StageCapture

Video•Download video from camcorder to computer

Edit Digital Video

(using Computer, Digital Video software

ex. Adobe Premiere, Avid)Edit itAdd all kinds of cool titlesFilters, transitions Superimpose clipsSynchronize audio with videoAuthoring software: create

menus and interactivity

Output Video•Output to different file formats

•Back out to tape, the Web, CD, DVD

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Ready to Make a Video IV

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Ready to Make a Video – Post Production

Capture Video

•Download video from camcorder to computer

Edit Digital Video(using Computer,

Digital Video softwareex. Adobe Premiere, Avid)

Edit itAdd all kinds of cool titlesFilters, transitions Superimpose clipsSynchronize audio with videoAuthoring software: create

menus and interactivity

Output Video•Output to different file formats

•Back out to tape, the Web, CD, DVD

Let’s take a closer look!

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Capturing Video –Download video from camcorder to computer

To use video in a multimedia application, it must be in digital form

So how do you get a camcorder video into digitized form?

_____________

____________

Video card

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(2) Video Capture Device

• Video Capture Card needed (if using analog camcorder from analog to digital)

• No need if source device outputs a digital signal (such as Firewire or USB)

(1) Source Device: Camcorders and digital video cameras can be used to capture full-motion images.

(Analog versus Digital)

(4) Computer: Download

video to edit

(5) Software: Capturing, Editing,

Outputting

(3) Connecting method

Five factors to consider when making a video

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Capturing Video

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Capturing Video –Video Capture Device

Analog Camcorder: Need Video capturing card

Digital Camcorder : Firewire connection

Audio

Video

•S video (better quality)

•Yellow RCA

Firewire

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Firewire vs. USB The Back Story

Firewire 400 created by Apple Apple wanted to charge 1 dollar for every machine that

was going to use it, this caused most PC manufacturers to decide against it, in favour of USB 1.1.

Transmitted originally at 400Mbps Peer to Peer Technology (can daisy chain one camcorder to

another WITHOUT a computer) USB 1.1. could transmit at 12Mbps

Used for mice, keyboards, printers, too slow for video USB 2.0 came along, backward compatible, transmitted at

480Mbps (could beat with Firewire400 and do video) Master/Slave technology (need to connect to a computer)

Currently, we have Firewire 800, transmits at 800 Mbps, at some point in the future, they expect new Firewire will transmit at 3.2 Gbps!

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Video Capture software should have the following features:

Start and stop the transferSelect a file format for storing your video footageSpecify file name for each video clip Video capture software is supplied with video editing software

and with video capture devices

TIP: Videos are easier to edit if you divide them into several files, each containing a one or two minute video clip.

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Controlling the Transfer Process

Capture Video(using video capture card)

from camcorder to computer

Edit Digital Video(using Computer,

Digital Video softwareex. Adobe Premiere, Avid)

Edit it Add all kinds of cool titles Filters, transitions and FX Superimpose clips Synchronize audio with

video Output in different file

formats

Output Video(back out to tape, the

Web, CD, DVD)

Editing Digital Video

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Video Editing Software I

Arrange video clips on time line

Add all kinds of cool titles

Filters, transitions

Superimpose clips

Synchronize audio with video

Output in different file formats

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Video Editing Software II

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Capture Video

(using video capture card )

from camcorder to computer

Edit Digital Video(using Computer,

Digital Video softwareex. Adobe Premiere, Avid)

Edit it Add all kinds of cool titles Filters, transitions and FX

Superimpose clips Synchronize audio with video Output in different file formats

Output Video

(back out to tape, the Web, CD, DVD)

Challenge:

Efficient Delivery via

Web44

Output Video

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Output Video

Why do we need codecs?Speed up downloads --- 10 times smaller than uncompressed video files. Without codecs, downloads would take 3-5x longer than they do now

There are different codecscodecs for audio and video compression, for streaming media over the Internet, videoconferencing, playing mp3's, speech, or screen capture The codec used to compress is the one needed to view

Two widely used media players:Apple’s QuickTime (QuickTime for Windows)MS Windows Media Player (uses AVI or WMV format ) Most media players including these will play videos produced with a variety of codecs

Which file type?

Answer the following 3 questions:

1. Is the video for the web, or for DVD, or if it is an older CD Rom, how fast is the playback?

2. Who is my audience? Will they have a Mac or a Windows machine? Perhaps

both, then you need a cross platform format. How will they watch it, on a computer, how old is the

computer, on a DVD player?

3. Will I be editing the video again later on? Maybe I don’t want to lose any data?

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Video Files

File Type

Also known as: Originally created by

More Info Platforms

.mov QuickTime movie Apple •Also for audio•Supports MIDI•Streaming with QuickTime Streaming Server•Can watch video as it is downloaded•Codecs Animation, Sorenson Video, H.264, PlanarRGB, Cinepak

Apple QuickTime player available for Mac and Windows

.avi Audio Video Interleave

Intel •Codecs Microsoft RLE, Intel Indeo Video, Cinepak

Mostly windows but Apple QuickTime player can play avi files

.rm Real Video Real Systems •High compression•Pick compression based on connection speed•Can stream with Real Server•Need for speed often compromises quality

Cross platformNeed Real Player

.wmv Windows Media Microsoft •Good compression Used with Windows Media Player

.mpg

.mpegMPEG Motion Picture

Experts Group•mpeg-1 VCD, •mpeg-2 DVD, •mpeg-4hand held devices (heavily compressed

Cross Platform

.flv Flash Video Adobe •Progressive download from webserver•Can be streamed with adobe Flash Media Server•Codecs Sorenson Spark, On2 VP6 (can have transparent video), H.264

Cross PlatformNeed Flash Player to play a SWF file that holds the flv file

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Exploring Video for the Web

Challenge: Transfer rate File Size

File TypeChallenge: Format

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Video Transfer for the Web

2 types of Video Transfer

HTTPHypertext Transfer Protocol

RTSPReal-Time Streaming Protocol

Download the Video from the

host (server) to the user’s computer in its digital form

• Played directly from the server to the user’s computer in a process called “streaming”.

• RTSP allows the user to perform tasks such as pause and play

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Video Transfer for the Web

HTTP RTSP• Downloads the entire

video to user computer

• User must wait for the download processto end

• Video can be played repeatedly and copied if necessary

Process called streaming

File played directly from server – thus some delay

Video is broadcast to user and after displayed, discarded

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small buffer space is created on the user's

computer

data starts downloading into it.

as soon as the buffer is full (usually just a

matter of seconds), the file starts to play

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The principle of streaming

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The principle of streaming

Advantages of StreamingWhat are the advantages of streaming over

downloading?1. Does not take up your Memory: Media files,

which tend to be large, are not saved to your hard drive where they would take up disk space.

2. Little Time: You don't have to wait long for the files to start playing.

3. Deliver in an effective way: Long programs, such as an entire class session, can be delivered over the web much more effectively.

4. Live broadcasting : Audio and video programs can be delivered live and archived simultaneously.

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Advantages of downloadable media filesWhy would one ever want to use downloadable

media files?

1. Readily available independent of server: Since a downloaded file is saved to your hard drive, it's available for later use, independent of the server.

2. Higher Image quality: Downloadable media can provide higher image quality. Streamed files are highly compressed so that they can

be delivered efficiently. With compression comes loss of image detail.

3. Step through frame-by-frame. One can quickly jump to any part of the audio or video track that one wants.

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Video for the Web RTSP – “Streaming” (also known as Webcasting)

Streaming requires a program to display streaming video Leading programs:

o Real Networks – Real Playero Microsoft - Windows Media Playero Apple – QuickTime Player

All 3 players work with popular video formats such as AVI, MPEG Webcasting of video events in real time such as concerts, conference

speakers.

Streaming is either On-Demand or Live. On demand are stored on the server for a long time and streamed based on a user request. Live would be used for a sporting event, election results, etc.

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How does Streaming Work?

Streaming is the process of taking a large audio or video file and transmitting small, continuous amounts of that file over a network.“STEADY and CONTINUOUS “ – File remains on server

Web server delivers pages to Web browsers over the Internet

RealServer serves media clips to clients. It allows users to stream, rather than download, the media clips.

Different Servers support different media formats 56

How does Streaming Work?

CONTINUOUS

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What if dealing with Large files!! What happens? Two methods:1. Progressive download. A click begins the download, but after some

portion had been downloaded, the movie would start to play How is it Done?

•The player (e.g., Windows Media Player) calculates the speed of the download, and guesses when to start playing the portion it has.

•The plan is to start late enough that the whole movie will be downloaded by the time you finish watching it.

2. True Streaming: File is NOT downloaded. Media begins to play as soon as it gets the packet

Advantages:•Fastest but requires that the server be set up to serve streaming media •Reduces waiting time required of the user•Drawback: Congestion on the net may cause the media to pause, if the downloading process can't keep up with the playback process. 

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Streaming Process:

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Streaming --

Points to Ram file (.ram) launches the RealPlayer and links to the clip

HTML webpage links to a ________

which _______________________

Syntax for a RamGen link:

http://streaming1.video.cornell.edu:8080/ramgen/courses/foldername/myvideo.rm 61

Video for Multimedia ApplicationsWhat should you consider when using video in Multimedia Applications?

Source:

Quality is tied to color resolutions, frames/sec, compression format

The higher the quality of the original video, the better the digitized version

Appropriateness:

Due to large video file sizes, poor quality of video clips, perhaps consider using animations or even still images instead of video

Playback Systems:

Web-based video may require browser plug-ins that the developer could make available through the application

User Control:

Provide the user with control options to start the video, jump to a section of the video, pause, stop, volume control.

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YouTube has changed many lives YouTube Video Awards:

Most Creative - Here It Goes Again OK Go Best Comedy - Smosh Short 2: Stranded Smosh Best Commentary - Hotness Prevails / Worst Video

Ever thewinekone Best Series - Ask A Ninja digtalfilmmaker Best Music Video - Say It's Possible Terra Naomi Most Inspirational - Free Hugs Campaign

PeaceOnEarth123 Most Adorable - Kiwi Madyeti47

YouTube

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