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 Formats AVI & 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 11-14 fps 30 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 Technologies http://www.microsoft.com/windows/windowsmedia/ RealSystem G2 http://www.realnetwork.com

Comparison WMT –vs- RealSystem G2 Head to head comparison Feature Comparison More Information http://www.microsoft.com/windows/windowsmedia/

Comparison WMT –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