Transcript Introduction to Streaming

Video Streaming
© Nanda Ganesan, Ph.D.
Video Streaming
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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
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Reduce setup time
Reduction in client storage requirement
Video can be viewed in real time
Transmission signals over low bandwidth
facilities
Video Streaming Architecture
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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
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AVI
ActiveMovie
Cinepak
Indeo
motion-JPEG
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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
– 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/window
smedia/
• RealSystem G2
http://www.realnetwork.com
Comparison
WMT –vs- RealSystem G2
• Head to head comparison
Feature Comparison
• More Information
http://www.microsoft.com/windows/windo
wsmedia/
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