Beth Kettenacker

Cully RadvillasSam Javner

Webcams, Streaming Video, and the Future

Webcams

What A Webcam Is

• A camera connected to the internet

• Most use the USB (Universal Serial Bus) to connect the camera to their computer

             

                     

                                   

             

                     

Personal Webcams

• This is the most common type of camera

• Used to share moving images of themselves or others

• Users can access this image by knowing a specific address to connect to

• Cameras are only available when the camera is connected and an internet connection exists

Buying a Webcam

Personal Use—Logitech or Creative Labs

We are using the Logitech QuickCam Pro

Professional Use—Sony PCS1600 (recommended by entrepreneur.com)

Need a high speed internet connection

Webcam Posting• An online webcam pointed at a specific scene or location

of interest to possible viewers

Most posted

webcams are

available 24/7

Webcams Around the World

Japanhttp://www.hbc.co.jp/susukino.html

San Franciscohttp://cbs5.com/cams/citycam/jumbo.html

Londonhttp://www.camvista.com/england/london/bigben.php3

               

                 

Video Conferencing

How Video Conferencing

Works• Uses a decoder that

changes analog video and audio signals into digital signals from cameras and microphones

• This digital signal is transmitted to a receiving site and is decoded back into the analog signal to be read

Digital Encoding

Transfers to ones and zeros

Creates an exact copy of the signal

Used by video conferencing and has greatly increased its quality

Television receives these signals from cameras and microphones

Used in old time televisions

Uses Approximate copies of the signals

Analog Signals

The Basics Of Video Conferencing

The combination of computer software, cameras, microphones, and other peripherals

Uses digital phone lines (ISDN lines) to transmit and receive information

Benefits of Video Conferencing

Allows interactive communication with people over any distance

The quality has greatly increased in recent years

History of Video Conferencing

1970’s First became available Not popular in the beginning becausebecause of high cost for

such poor quality

1990’s Digital Communication through ISDN services started Started a foundational network capability that created

many technologies—Video Conferencing

Video Conferencing Today

o Network technologies are popular in most office environments

o Software and services are easily available to general public and is affordable

o It is a top choice for businesses because it is economical, safe, and saves time

Popular Types of Video Conferencing Systems

• Webcams– Popular among consumers

• Set-Top Designs– Popular for professional use

• Integrated Systems

Streaming

What is Streaming?

• Process of viewing media while it is being downloaded

• Usually refers to video or audio

• Audio is usually higher quality– Smaller file size– Less compression needed

Streaming Media Distribution

• Web Server– TCP protocol

• Does not sacrifice data – not always real time

• Has to be able to determine bandwidth speed

• Media Server– UDP protocol

• Sends data at a predetermined rate

• Allows for some lost information

Hardware and Software Needed for Broadcasting

•The device (a webcam)•Media Server•WWW connection•Compression Software

             

                     

FishCam

• Our HTTP FishCam

Options for Online Video

Download entire videoOn-Demand Video

Streaming“Live” Video Streaming

Downloading an Entire Video

The only option before streaming videoProblems

Video files are largeLarge delays between starting downloading video and watching it

SolutionStreaming video

Benefits of Downloading an Entire Video

• Higher Quality

• Video can be saved to the computer and viewed at any time

On Demand Streaming

PROCESSPROCESS• Media player program

starts downloading a program

• Starts to fill a buffer• When buffer is filled,

playback begins

Benefits of On-Demand Streaming• Video can be viewed at any

time without waiting for the entire file to download

• Speed of the media is not constant, so placing the next frames in a buffer prepares them to be played smoothly

“Live” Streaming Video Process

• Frame is displayed to the screen as soon as it can after the frame is received

• Video quality is usually lower than buffered video due to variations in download speed

• Video also may look jerky because each frame has an individual download speed

Three Major Players for Streaming Video

• Widows Media Player by Microsoft

• QuickTime by Apple• RealPlayer by RealNetworks

• Most popular format for streaming

• Allows streaming different quality video from the same video source

Has video of a higher quality than RealPlayerDisadvantage

Requires different sources in order to vary quality

Windows Media Player

QuickTimeHas the best and most consistent qualityUsed by the movie industryThis version is the least popular format of streaming

Video

Compression

Video Compression

• One minute of uncompressed DVD-quality video would require ~ 1.6 gigabytes

• Without compression, a DVD could only hold 3-12 minutes of video

• Nearly impossible to stream uncompressed video over the Internet – Compression is absolutely necessary

Interframe Compression

• Takes advantages of similarities between adjacent frames (temporal redundancy)

• Only store information on parts of video that are changing

Interframe Compression Techniques

Sub-samplingOnly store “necessary frames”

Our brains can fill in the missing information

Difference CodingOnly store data on pixels that have changed

Motion CompensationStore how fast an object (or block of pixels) is moving and which direction it is moving

Compression Difficulties

• Less movement, better compression

• A lot of motion in video or a rapidly moving camera makes it hard to compress – lots of pixels are changing

Compression Rate Vs. Quality

Experiments with Compression Rate

•We recorded a video

•We compressed it at various bit rates

•Observed how changing the bit rate affects video quality

Sample Videos

• Non-Moving Camera– Video for Dial-up

– Video for ISDN

– Video for Broadband (low quality)

– Video for Broadband (high quality)

– Video for LAN

• Moving Camera– Video for Dial-up

– Video for ISDN

– Video for Broadband (low quality)

– Video for Broadband (high quality)

– Video for LAN

Findings

• Higher bandwidth will allow for higher bit rates and less compression, which means higher quality

• Video taken with a non-moving camera has higher quality than video taken with a moving camera

Future of

Webcams

Future of Video Compression:

MPEG-4 StandardCreates files of same quality and half the size of MPEG-2 files.

MPEG-2 files are used in DVDs

It is supported in Apple, Microsoft, and RealNetworks video files

Artificial Intelligence (AI)

• It is in compression software– Determines what information is

needed to convey the message in the information

• For Example: – A ball is bouncing on one side of the

scene and a stationary object is on the other side. The pixels in the area of the moving object will change while the other side is not refreshed

• Also involved with downloading information from the server to the client

Future: Integration

• The goal is to have many different types of media (pictures, sounds, music, video, etc.) may be stored together in one file

• Information displayed depends on the type of device will be reading it

• Work has already begun using the MPEG-21 standard

Future: Solving Network Congestion

AI uses the software to determine which part of the multimedia real-time transfer (audio and video) to remove information fromDecreases bandwidth usage

Ex: the frame rate or quality of video can be automatically reduced wile keeping the data transfer real-time and the sound quality consistent

Future: 3D Video

• Has become a topic of discussion• Difficulties:

– File size– Decoding of information by the user

• Think about a 3D movie where the image needed to be decoded by a device that separated images into right and left (stereographic)

Microsoft and 3D Video

•Currently developing software•Uses two cameras to achieve

a stereographic effect•Uses an algorithm to separate

the images into a 3D representation

Future: Bandwidth

Bandwidth of most connections is increasing

This means there will be more viability in streaming media because it will become available to more users

DDCam Project

How the Camera Works

• Process of developing camera image:– Camera driver calls framecallback code

– Framecallback either manipulates the data or leaves it alone

– Image is then put back into memory

– User sees the image on the screen» (information from Drew Demerath’s

documentation)

Using Usercallback

• We took Drew’s source code and added our own callback routines

• Usercallback provides us with an array of raw video data

• Each pixel in this array is composed of red, green, and blue components

• We can change the values in this array to change the image that is displayed

Our Features Added

• Grayscale – his code did not function correctly

• Flip Image

• Mirror Image

• Negative Image

• Adjust Red/Green/Blue Percentages