Transcript Streaming Video over the Internet: Approaches and Directions

Streaming Video over the
Internet: Approaches and
Directions
Dapeng Wu, Yiwei Thomas Hou et al.
Presented by: Abhishek Gupta {[email protected]}
Introduction
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Issues in Video Streaming.
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Transmission of Real Time Video typically has
bandwidth and delay requirements.
Current Internet does not offer any QoS guarantees
to streaming video.
For multicast it is difficult to achieve both efficiency
and flexibility.
Overview
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Key areas in streaming video.
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Video Compression – Scalable and
Nonscalable coding.
Application-layer QoS control.
Continuous media distribution services.
Streaming servers.
Media synchronization mechanisms.
Protocols for streaming media.
Architecture For Streaming Video
Video Compression
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Nonscalable Video Coding.
Nonscalable video Encoder
Nonscalable video Encoder
Video Compression(contd.)
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Scalable Video Encoding.
Scalable video encoder
Scalable video decoder
Application Requirements from
Encoder and Decoder
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Bandwidth – Rate control.
Delay - Buffering.
Loss – Multiple description coding.
Video Cassette recorder like functions.
Decoding Complexity.
Application Layer QoS Control
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Congestion Control
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Rate Control
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Source Based – Probe based, Model based (“TCP friendly”)
Receiver Based – Channel based, Model based.
Hybrid Rate Control – Destination set grouping and layered
multicast scheme.
Rate Shaping – Match the rate of a pre-compressed
bitstream to a target rate by use of filters.
Application Layer QoS Control
(contd.)
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Error Control
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Forward Error Correction (FEC) – Channel
coding, Source coding, Joint channel/source
coding.
Delay-Constrained Retransmission.
Error-resilient coding – Multiple description
coding.
Error concealment – Spatial and Temporal
Interpolation.
Continuous Media Distribution
Services
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Network filtering.
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Application level multicast.
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Improved video quality.
Bandwidth efficiency.
Media bridges-Interconnection of media multicast
networks enabled through application level peering
relationships.
Content replication.
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Caching
Mirroring
Streaming Servers
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Components.
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Communicator – Application layer and
transport protocols.
Operating System – Real time support for
streaming applications.
Storage System – Support for continuous
media storage and retrieval.
Streaming Servers (contd.)
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Real Time Operating Systems
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Process management – EDF and ratemonotonic scheduling.
Resource Management - Admission Control,
Resource Allocation.
File Management
Streaming Servers (contd.)
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Storage System
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Increase throughput with data stripping.
Increase capacity with tertiary and
hierarchical storage.
Use SAN, NAS.
Fault tolerance.
Media Synchronization
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Intra-stream synchronization – Within a
time dependent data stream.
Inter-stream synchronization – Between
different time dependent data streams.
Inter-object synchronization – Between
time dependent and time independent
data.
Protocols for Streaming Video
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Network layer protocols – IP.
Transport protocols – TCP, UDP, RTP, RTCP.
Session control protocols – RTSP, SIP.
Protocols for Streaming Video
(contd.)
Protocol Stacks for Media Streaming
Protocols for Streaming Video
(contd.)
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Transport Protocols – RTP and RTCP.
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RTP
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Time Stamping
Sequence numbering
Payload type identification
Source identification
RTCP
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QoS Feedback
Participant information
Control packets scaling
Inter-media synchronization
Minimal session control information.
Protocols for Streaming Video
(contd.)
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Session control protocols – RTSP and SIP
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RTSP
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Support VCR like options
Provide means for choosing delivery channels and
delivery mechanisms based upon RTP.
Media retrieval
Adding media to existing session.
SIP – Similar to RTSP but supports user
mobility.
Future Directions
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Video Compression – How about using a combination of encoding
schemes?
Application Level QoS – The effectiveness of TCP like rate control.
Continuous media distribution services – A scalable, cost-effective,
efficient and incremental deployable infrastructure for continuous
media distribution.
Streaming servers – VCR like control, Storage mechanisms,
scalability, fault tolerance.
Media synchronization – Synchronization in multicast video while
supporting VCR-like interactive functions.
Protocols – Caching, support for pause/resume operation in caches,
security in protocols.