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
AVI ActiveMovie Cinepak Indeo motion-JPEG MPEG QuickTime RealVideo Video for Windows XGA Video Input Formats
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 Technologies http://www.microsoft.com/windows/windowsmedia/ • RealSystem G2 http://www.realnetwork.com
ComparisonWMT –vs- RealSystem G2 • Head to head comparison Feature 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
