Cs- Distributed Video Streaming Over Internet

8/14/2019 Cs- Distributed Video Streaming Over Internet

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Technical Seminar Presentation

Presented by : SARAT KUMAR BEHERA N A T

I O N A L I N S T I T U T E

O F S C I E N C E

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[1]

Presented By

SARAT KUMAR BEHERA Roll # CS 200117230

NATIONAL INSTITUTE OF SCIENCE AND TECHNOLOGY

DISTRIBUTED VIDEO STREAMING

OVER INTERNETUnder the guidance of

Mr. Dutikrushna Panda






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[2]

It is defined as streaming video from multiplesenders simultaneously to a single receiver.

It is also called a Multiple Sender Video

Streaming (MSVS) system.Example:

two or more senders

senders sending

simultaneously at

different rate

DISTRIBUTED VIDEO STREAMING

S1

S2

S3

Receiver

400kbps

300kbps

100kbps






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ADVANTAGES OF MSVS SYSTEM

MSVS uses aggregated bandwidth to ease

bandwidth requirements of video

streaming.

MSVS combat loss using path diversity,

offering higher stability and higher

quality of service.






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ISSUES ON MSVS SYSTEM

Encoding and Decoding

Multilayered Coding

Fine Granularity Scalability(FGS)

Transmission Protocol

Sender selection






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ENCODING AND DECODING

Compression is employed to achieve transmissionefficiency. Some important streaming requirementsare:

Bandwidth

Delay

Loss

VCR

Codec efficiencyDecodable and composable

Bandwidth utilization






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COMPRESSION SCHEME

A scalable video encoder compresses a raw video

sequence to multiple sub-streams.

Two sub-streams are generated, namely the “Base

Layer (BL)” and the Enhancement layer (EL).

DCT

Q VLC

IQ

VLCQ VLD IDCTIQ

IDCTVLD IQ

Base Layer

compressed

Bit-stream

Enhanceme

nt Layer

Compressed

Bit-stream

Base layer

decoded

video

Enhanced

layer

decoded

video

Raw

video






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Fine Granularity Scalability

FGS uses bit-plane coding instead of traditionalrun-level coding of DCT coefficients to achievethe continuous quality curve.

Bit-plane coding considers each quantized DCT

coefficient as a binary number of several bitsrather than a decimal integer of a certain value.

For each DCT block we have 64 DCTcoefficients zigzagged into an array

e.g. 10DEC

1010BIN

The number of bit-plane is determined by thelargest value of all DCT coefficients.

→

8

8 ×






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TRANSMISSION PROTOCOL

The goal of designing a transmission

protocol is to ease constraints like

bandwidth, loss rate and latency.

There are two aspects in transmissionprotocol:

– Who to send

– What to send






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WHO TO SEND

This protocol measures the suitability for a host to be a

streaming server is required in this protocol. This

measurement may focus on bandwidth, loss, latency

or path diversity as:

Maximize bandwidth

Minimize overall loss rate

Minimize latency(delay)

Reduce correlation between paths






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WHAT TO SEND

This is divided into three aspects:

How to divide the media data

How to distribute

How to use retransmission

Retransmission from original sender

Retransmission from other senders

Retransmission from dedicated retransmitter






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The transport protocol is a receiver-driven one in

which, the receiver coordinates transmissions from

multiple senders based on the information received

from the senders.

Factors affecting transport protocol

Bandwidth EstimationRate Allocation Algorithm

Packet Partition Algorithm (PPA)

TRANSPORT PROTOCOL FOR

RECEIVER SECTION




Presented by : SARAT KUMAR BEHERA N A T I O N A L I N S T I T U T E

O F S C I E N C E

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BANDWIDTH ESTIMATION

The receiver estimates available bandwidth for each sender based on

the TCP-friendly rate control algorithm (TFRC).

It calculates the available bandwidth according to the followingequation

where B=current available TCP-friendly bandwidth between each sender and

the receiver

T rto

=TCP time out

R = estimated round-trip time

p = estimated loss rate

s =TCP segment size in bytes

)321()8

33(

3

2 2 p p p

T p

R

s B

rto ++

=





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RATE ALLOCATION ALGORITHM

• In this protocol, the receiver computes the

optimal sending rate for each sender based on its

loss rate and estimated available bandwidth.

Let N=total no. of senders

L(i,t) =estimated loss rate

S(i,t) = estimated sending rate

Sreq(t)= the required bit ratefor the encoded video

)(),(

),(),(0

),(),()(

1

1

t S t iS

t i Bt iS where

t iS t i Lt F

req

N

i

N

i

=

≤≤

=

∑

∑

=

=





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PACKET PARTITION ALGORITHM

After receiving the control packet from thereceiver, each sender immediately decides thenext packet in the video stream to be sent, usingthe packet partition algorithm.

All the senders simultaneously run this algorithmto ensure that no sender sends the same videopacket, and also to minimize the probability of packets arriving late at the receiver due tonetwork jitter.

The format of the control packet is shown here(for simplicity, the IP header and sequence number isnot shown).




Presented by : SARAT KUMAR BEHERA N A T I O N A L I N S T I T

U T E

O F S C I E N C E

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T E C H N

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[15]

S1-S5 are two-byte fields to specify the sending rate in

packets/second for each sender.

D1-D5 are one-byte fields to denote the estimated delay

from each sender to the receiver.

The Sync field is the starting sequence number that allsenders use in the packet partition algorithm to

determine the next packet to send, immediately upon

receiving the control packet.

D1 D2 D3 D4 D5 S1 S2 S3 S4 S5 sync




Presented by : SARAT KUMAR BEHERA N A T I O N A L I N S T I T

U T E

O F S C I E N C E

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CONCLUSION

• A framework for a MSVS is proposed in order to achieve higher throughput, and to increasetolerance, to loss and delay due to congestion.

• This results in lower distortion than distributed

video streaming in a simplistic, non-adaptivefashion.

• It is speculated that the MSE will be evensmaller if the protocol can be extended to

allocate video bits based on their importance.




Presented by : SARAT KUMAR BEHERAN A T I O N A L I N S T I T

U T E

O F S C I E N

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Thank You…

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Cs- Distributed Video Streaming Over Internet