Introduction to Multimedia

Lecture #9Intro to Video

Instructors: Mohamed MAGANGA

Today’s Agenda

1. Announcements

2. Warm Up

3. Today’s Lecture Lect 9: Intro to Video

3 Topics Left•Video (pt.2)

•Sound (1)

•Review (1)

“A good film is when the price of the dinner, the theatre admission and the babysitter were worth it.” Alfred Hitchcock

EVERYTHING MUST BE WORKING TEST IT ALL

Major Assignment - 10%

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Marking Criteria:

1. Technical: file organization, file names (lower case)

2. Color creativity

3. Website Design: content, layout, style, links

4. Video – Word Overlay, transitions, music, style

5. Animation: creativeness and how it was incorporated in the website

Warm Up QuestionsWhich of the following terms means:

“seeing two or three of the previous frames in order to predict where to put the next frame”

a) Tweening

b) Onion Skin

c) Morphing

Tweening: Process of ___________________________ to give the appearance that the first image evolves smoothly into the second image.

Onion Skin: Creating animated cartoons and editing movies to see ____________________

Morphing: Process of blending together _______________ into a series of images

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Warm up Questions:Warm up Questions:1. Question: How many frames per second should we have

when building an animation for display on a computer?

2. Question: Which type of animation uses frames:

A. Cel Based

B. Path Based

C. Both

D. Neither

3. Question: If an animation is 40 frames long and the fps is 5, how long will the animation take to play?

Today’s Agenda

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Video – Part 1 What is Video Capturing Video Firewire vs USB Editing Video How TV Works Review

What is Video?

Movies

Display at ______ fps

Computer Displayed Video

Display at ________ fps for smoothness

Video uses the power of Motion and Sound

A sequence of still images or frames that create the illusion of movement when played in succession.

2 Types of Video:2 Types of Video:Analog: Smooth ___________ waves ex. Conventional TV

Digital: Each frame is a _____________, stored as 0s and 1s

Digital Video

Digital Video is composed of a series of bitmap graphics, each one called a ____________.

Characteristics:

• Bits store color and brightness data for each video frame.

• Retains image quality no matter how many times it is copied.

• Easily manipulated on a pc because stored in digital format

“Digital Technology is the same revolution as adding sound to pictures and the same revolution as adding color to pictures. Nothing more and nothing less.”

- George Lucas, film maker of STAR Wars

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

http://www.youtube.com/watch?v=FvQV21hkMjI&feature=related (we will just watch the first 2 minutes)

How much planning goes into making a movie before the first

scene is ever shot?

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Creating Digital Video

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Ready to Make a Video –Assumption: you took the footage

Capture 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

Let’s take a closer look!

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Capturing the Video with Capturing the Video with CamcordersCamcorders

If we use an:If we use an: Analog CamcorderAnalog Camcorder,:,:• Electronic impulses are recordedElectronic impulses are recorded• Must convert it to digital BEFORE we can put it on our computer Must convert it to digital BEFORE we can put it on our computer

to edit. to edit. • To convert analog video to digital video we need a To convert analog video to digital video we need a ______________________

Digital Video Camcorder:Digital Video Camcorder:• Information is sent as _____________Information is sent as _____________• Thus no need to convert!Thus no need to convert!

Capturing Video –Download video from camcorder to computer

To use video in a multimedia application,

it must be in digital form (0s and 1s)So how do you get a camcorder video into digitized form?

Analog Video

camera

Digital camera

Video card

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Software: Capturing,

Editing, Outputting

Connecting Leads:

Firewire or USB cable

Digital Video CamcordersDigital Video Camcorders

Most Digital Video Camcorders (DV Camcorders), do a little bit of compression right inside the camera.

common DV compression used by today’s camcorders: DV25 is the most DV25 Format Specs:DV25 Format Specs:

Pixel Dimension is Pixel Dimension is 720 X 480 720 X 480 (note this is (note this is 3:2 ratio3:2 ratio)) Frame Aspect Ratio either Frame Aspect Ratio either 4:3 or 16:94:3 or 16:9 Data Rate: 25 mega bits per second (that’s why it Data Rate: 25 mega bits per second (that’s why it

is DV25)is DV25) Frame Rate: 29.97 fpsFrame Rate: 29.97 fps Colour Sampling: YUV 4:1:1Colour Sampling: YUV 4:1:1

For still images RGB is commonly used For video the model is YUV (YIQ) or YCbCr (for MPEG

compression) Y luminanace (brightness) UV (CbCr) chrominance (color/hue)

Question: Black and White TV only used the _____ signal (fill in the blank with Y, U or V)Answer: ______________________

Question: Which one will the human eye detect changes in more easily? How does this help us with compression?

Answer:________________

Colour CompressionColour Compression In The Camera In The Camera

Color Sampling Method for Video-compression technique

You may see that the compression used

4:1:1 4:2:0 4:4:4 What does this mean?

Assume we have 4 pixels

Color Sampling: Refers to technique in digital video –compression technique

BACKGROUND: in Video we do not store record all color in an image

• Color Sampling allows Averages out pixels to cut down on bandwidth (faster transfer rates)

• Eye senstivity:

•Rods – light vs. dark, black vs. white -- not color

•Cones – see color

• We can detect brightness better than color (more rods)

Color Sampling Method for Video

You may see that the compression used 4:1:1 Color Sampling

Method, What does this mean? Assume we have 4 pixels

http://dvxuser.com/articles/colorspace/

Red, Orange, Blue, Purple

red + blue = Purple

•4:2:0

•Blocks of 4 pixels averaged out

•2x2 grid block

• 4:1:1• Blocks of 4 pixels

averaged out

• 4 x 1 blockResult: So all four pixels get forced to become purple (shades of brightness)

Blocks of 4 pixels averaged out

Color Sampling Method for Video

Color Sampling Method

Amount of Y (luminance)

Amount of U (color or hue)

Amount of V (color or hue)

Amount of Compression

Used in

4:4:4 4 samples 4 samples 4 samples None12 samples for each group of 4 pixels

4:2:2 4 samples 2 samples 2 samples Reduced from 12 samples to 8, 33% reduction in storage

Digital Betacam format

4:2:0 4 samples 2 samples of either U or V, one scan line of U, then one scan line of V

12 to 6, 50% reduction in storage

HDV, MPEG-1, DVD, MPEG-2, PAL DV

4:1:1 4 samples 1 sample 1 sample 12 to 6, 50% reduction in storage

NTSC DV, miniDV digital camcorder

http://dvxuser.com/articles/colorspace

/

Sony Hi-8 TRV-80

Audio

Video•S video (better quality)

•Yellow RCA

Firewire

connection

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Connection Types:

Firewire

Video Capture CardPlugs directly

Firewire (4 pin)

USB

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USB cables

To get the video off of your camera onto a computer you must use either:

• Converts video from ANALOG TO DIGITAL

Capturing Video –Video Capture DeviceDownload video from camcorder to computer

Firewire ( ________, _________) A means by which information could be sent from the camcorder

directly to the computer

A high-speed digital serial _________that allows the output of the camera to be fed directly into a computer in digitized form

Digital Video footage requires 13GB of storage per hour of video.

All major manufacturers agreed to use a common digital tape format and a method -- Firewire (universal standard)

•4-pin to 4-pin plugs

•4-pin to 6-pin plugs

•6-pin to 6-pin plugs22

Summarizing Analog vs Digital

ANALOG (Older Technology )

• Records electrical signals/pulses directly onto a medium (like a tape) with a magnetic encoding.

• Disadv: Picture loses quality

Video capture card needed to convert video from analog to digital for your computer

DIGITAL (Newer Technology)

• Records a binary code (string of 1s and 0s) compressed on magnetic tape or other media

• Adv: No image degradation

Plug your video camera directly into your computer via a Firewire (aka i.Link) or USB connection.

These are digital connections and allow you to "dump" footage straight from the camera to

hard drive.

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1983

1994

Solid State Media Card - Memory Sticks

A little history on TVs

Digital video often adheres to standards for TV broadcasting – 2 standards

NTSC Standard: Regular Analog TV broadcasting began in the United

States in 1939 and carried through to today Frame rate was originally 30fps but when color was

introduced, needed to go down to _______ fps to accommodate for colour information.

PAL Standard: Britain, Europe and other countries Frame rate is set for _________ fps

Experiments with High Definition TV began in the late 40s and 50s but it wasn’t adopted by a single station till 1996.

Before 1996 ALL TV was broadcast using _________________(see next slide)

The original ANALOG video choices made about TV display (frames per second, frame size, etc..) affect the standards that were picked for DIGITAL video and applied today!

A little history on TVs

How did the original TV display work?

Our eyes see phosphor dots on the screen. An electron beam (gun) activates the dots.

The gun scans through the dots horizontally A complete scan is when the gun starts at

the top left and scans several times horizontally till it gets to the bottom right

The scan only draws every OTHER line (1,3, 5, …479) then starts back at the top and draws the even lines (2,4,…480). Thus two passes Each pass is called a field The process is called Interlaced

display

This way it can cheat the eye, while the phosphor dots are disappearing, it is

drawing the line underneath.

http://www.crutchfield.com/Learn/learningcenter/home/understanding-resolution.html

Increasing the frame rate in the old days required a lot more bandwidth, so they “cheated” and used interlacing to trick the eye

Interlacing effect (old TVs)

Line 1,3,5,7,

Line 2,4,6,8..

Progressive effect( not interlaced)(now used by Flat Screens because of the panel)

Line 1,2,3,4,5,6,7..

How did the original TV display work?

NTSC StandardsNTSC Standards

NTSC Standard DV Frame:NTSC Standard DV Frame: For NTSC For NTSC 720 X 480 pixels 720 X 480 pixels

For Pal For Pal 720 X 576 pixels 720 X 576 pixels Pixels are distorted (not square) Pixels are distorted (not square)

because 720:480 is actually 3:2 because 720:480 is actually 3:2 ratioratio

4:3 Frame aspect ratio

16:9 Frame aspect ratio

Frame aspect ratio is the ratio of width to height of the image frame.

High Definition for NTSC:High Definition for NTSC: 1440 X 10801440 X 1080 1280 X 7201280 X 720 Frame Aspect Ratio is 16:9Frame Aspect Ratio is 16:9 1440:1080 1440:1080 ratio is 1.333 ratio is 1.333

(pixels are not square)(pixels are not square) 1280:720 1280:720 ratio is 16:9 ratio is 16:9

(pixel are square (pixel are square ))

How do we see images on a CRT Display TV vs Flat Screen

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http://www.crutchfield.com/Learn/learningcenter/home/understanding-resolution.html

Older TVs Older TVs 480 Scan Lines New Plasma, Flat Screen New Plasma, Flat Screen 720 or 1080 lines

progressive not interlaced

http://www.crutchfield.com/learn/learningcenter/home/tv_flatpanel.html?page=2http://www.crutchfield.com/S-EMMmc3InSom/learn/learningcenter/home/tv_flatpanel.htmlhttp://www.crutchfield.com/Learn/learningcenter/home/understanding-resolution.html?page=2

OLDER TECHNOLOGY

-Screen resolution __________

-Electron gun beam activates the dots

PLASMA or LCD

Screen resoluiton sof _________

_________

Flat grid of pixels

How do we see images on a Flat Panel TV

Most flat-panel TVs are progressive displays

Don’t need to know more detail for the exam

• Illuminating a fixed grid of tiny pixels.pixels.

• Every pixel has three sub-pixels: (RGB)

• Color and brightness information controlled at the sub-pixel level

• Uses progressive display

Screen resolutions of

1080p (progressive)1080i (interlacing)

Capturing Video –Download video from camcorder to computer

Resolution Comparison

FormatLines of Resolution (measurement of image quality)

VHS, VHS-C 240 lines

8mm 240 lines

Hi 8mm 400 lines

Most older TVs (standard, SDTV)

480 lines

DV 8mm, Mini DV

480 lines

High Definition (HD) TV

720 linesOr 1080 lines32

Digital Advantage:higher resolution (# of horizontal lines)

Depending on features of individual unit, you may be able to achieve:

Newer TVsNewer TVs

Question: On a newer HD TV, what Question: On a newer HD TV, what does the circled area mean?does the circled area mean?

http://www.crutchfield.com/Learn/learningcenter/home/understanding-resolution.html

Apple IPODS no longer have firewire ports

Firewire vs. USB

Firewire Firewire initiated by Apple and the IEEE

in the late 80s. It is a high speed data transfer

technology. Transmitted originally at 400Mbps 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.

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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USB USB 1.1. could transmit at

12Mbps Used for mice, keyboards,

printers, _____________ USB 2.0 came along,

backward compatible, transmitted at 480Mbps (could beat with Firewire400 and do

video)

It used to take A LONG time to move video from your camcorder to your computer (Hours and Hours)

Capturing Video Download video from camcorder to computer

Benefits of Digital

• No Loss of Quality – Digital Videotape can be copied almost indefinitly. Important consideration in Postproduction sessions that require numerous generations of video effects.

• No need of analog-to-digital conversion Digital material can be directly uploaded to digital editing systems

• Reduces or eliminates problems such as dropouts due to error-correction circuitry associated with digital electronics

• Archival (long-term) storage. Digital videotapes are better suited for longer periods

• Quality of digital recordings is significantly better than analog recordings

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Capturing Video Download video from camcorder to computer

Controlling the Transfer Process

• Video Capture software: Doesn’t matter if you are using an analog or digital camera

Software Should have Features:

• Start and stop the transfer• Select a file format for storing your video footage• Specify 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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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)

In Lab – MovieMakerLearning to edit your video

In Lab – MovieMaker

Movie on Adobe Premier37

Let’s Review When would you use Firewire?

If you have a digital camcorder If you have an analog camcorder

Which of the following is a benefit of using a digital video recorder? No loss of data Can edit digital footage on a computer, you can NOT edit analog

footage on a computer. You don’t need a video capture card All of the above are benefits of going digital.

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