Video Streaming

© Nanda Ganesan, Ph.D.

Video Streaming

• Video Streaming Objective• Streaming Advantages• Video Streaming Architecture• Compression and Decompression-codec• MPEG 1-4 Introduction• Major Products and Features

Comparison

Video Streaming Objective

• The object is to overcome the negative effects of physical distance and network technology limitation.

Streaming Advantages

• Reduce setup time• Reduction in client storage requirement• Video can be viewed in real time • Transmission signals over low

bandwidth facilities

Video Streaming Architecture

• Content Creation/Capture• Content Management• Content Formatting (Compression)• Delivery• Distribution• Presentation (Viewing)• View Control

Video Capture

• Converting analog to video signals– A special video capture card to

convert the analog signals to digital form and compresses the data.

– Also digital video devices that can capture images and transfer to a computer

Content Management

• Critical in video server• The purpose including create, collect,

catalog, organize, store, and access to massive multimedia information database

Video Input Formats

• AVI• ActiveMovie• Cinepak• Indeo• motion-JPEG

• MPEG• QuickTime• RealVideo• Video for

Windows• XGA

Video FormatsAVI & ASF

• Developed by Microsoft• AVI (Audio Video Interleaved)

- limited to 320x240 resolution- 30 frames per second

• ASF (Advanced Streaming Format)- Has been submitted to ISO for standardization- Expected to replace AVI format

Standard Window Size

• 320X240• 640X480

Frame Rates

• 4-6 fps– Absolute minimum for video

conferencing

• 11-14 fps – The norm for video conferencing

• 30 fps– Full motion video

Codec(Compressor/Decompressor)

• Coding techniques to compress video data

• The newest codec change their sampling rate as they run

• Choice of codec is the biggest factor to determine the bandwidth needed to connect the server and receive content

• Many of the codecs follow international standards

Content Compression

• MPEG (A working group of ISO)- The most common standard for video

compression and file formats- Generally produce better quality video than other

formats- High compression rate- MPEG1, MPEG2, MPEG3 and MPEG4

MPEG-1

• MPEG-1 was designed for coding progressive video at a transmission rate of about 1.5 million bits per second.

• It was designed specifically for Video-CD and CD-i media.

• MPEG-1 audio layer-3 (MP3) has also evolved from early MPEG work.

MPEG-2

• MPEG-2 was designed for coding interlaced images at transmission rates above 4 million bits per second.

• MPEG-2 is used for digital TV broadcast and

DVD.

• An MPEG-2 player can handle MPEG-1 data as well.

MPEG-3

• A proposed MPEG-3 standard, intended for High Definition TV (HDTV), was merged with the MPEG-2 standard when it became apparent that the MPEG-2 standard met the HDTV requirements.

MPEG-4

• An MPEG-4 standard is in the final stages of development and release.

• It is a much more ambitious standard and addresses speech and video synthesis, fractal geometry, computer visualization, and an artificial intelligence (AI) approach to reconstructing images.

Video Streaming Standards

• H.261• H.263• MPEG1• MPEG2• MPEG4

H.261

• H.261 is use for teleconferencing applications and is intended for carrying video over ISDN.

• H.261 needs substantially less CPU power for real-time encoding than MPEG.

• H.261 uses constant-bit-rate encoding.

H.263

• H.263 is design for low bitrate communication.

• H.263 expected to be use for wide range of bitrate and expected to replace H.261.

• H.263 supports 5 resolutions, able to compete with MPEG standards.

TCP Transmission Control Protocol

• Protocol used for reliable document transfer

• HTTP (Hypertext Transfer Protocol) uses TCP as the protocol for reliable document transfer.

• Unsuitable for video and audio because: • Imposes flow control• Unnecessary Message delivery

UDP User Datagram Protocol

• UDP is the alternative to TCP. • UDP forsakes TCP's error

correction and allows packets to drop out if they're late or damaged.

• Access Problems (firewalls).

Some Real-Time Transmission Related Protocols

• RTP• VDP• RTSP• RSVP

Major Products

• Microsoft Windows Media Technologieshttp://www.microsoft.com/windows/windowsmedia/

• RealSystem G2 http://www.realnetwork.com

ComparisonWMT –vs- RealSystem G2

• Head to head comparisonFeature Comparison

• More Information http://www.microsoft.com/windows/windowsmedia/

ComparisonWMT –vs- RealSystem G2

• Cost Analysis- Prepared by Approach, Inc.,

• Key findings - Both streaming products results in positive

returns on investment - Microsoft solution is more economical than the

RealNetwork solution• Download in Word format

Audio Streaming Architecture

• Creating Audio File• Demonstration of Streaming Software• Demo of Streaming Process

– Windows Media Encoder – RealProducer 7 Basic

• Play the Audio File