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  Effect
of  CBR and VBR traffic on SVC Streaming
over Wireless Networks                                                

 

 

Heena Gupta

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Lecturer,
Computer Department

GCET,
Jammu

[email protected]

 

 

Dr. Simmi Dutta

Associate
Professor, Computer Department

GCET, Jammu

[email protected]

 

 

Abstract— For streaming
applications UDP is used as transport protocol. The reason for choosing UDP is
that the latency which can be introduced by retransmissions when using TCP is
not suitable for video streaming and the video streams are loss tolerant to
some extent. Since UDP does not provide congestion control, the application
layer must provide this function. Scalable video coding compression technique
is used to provide the scalability of the video bit stream.The study of effect of constant and variable bit rate of SVC video
format gives us the idea that if
the network traffic in the wireless network is less it is desirable to send the
video packets at a constant rate otherwise some optimization tools must be used.

 

                                                                                                                                                                
I.         
Introduction

A. Video Streaming

The video delivery, systems are broadly
classified as streaming and broadcast systems1. The main idea of video
streaming is to divide the video into small parts, transmit these parts in succession,
and enable the receiver to decode and playback the video as these parts are
received, without having to wait for the entire video to be delivered. Video
streaming can conceptually be thought to consist of the follow steps:

1) Partition the compressed video
into packets

2) Start delivery of these
packets

3) Begin decoding and playback at
the receiver while the video is still being delivered.

Video streaming over wireless networks is compelling
for many applications, ranging from home entertainment to surveillance to
search-and-rescue operations .While video streaming requires a steady flow of
information and delivery of packets by a deadline, wireless radio networks have
difficulties to provide such a service reliably .As the wireless link quality
varies, video transmission rate needs to be adapted accordingly. In case of
video streaming, commercial applications and most research work use
conventional hybrid video coding. In case of video-on-demand, the data rate of
a hybrid coded bit stream can be coarsely adapted by dropping frames with lower
priority or by extensive transcoding.

There are a number of basic problems that afflict
video streaming. Video streaming over the Internet is difficult because the
Internet only offers best effort service. That is, it provides no guarantees on
bandwidth, delay jitter, or loss rate. Specifically, these characteristics are
unknown and dynamic. Therefore, a key goal of video streaming is to design a
system to reliably deliver high-quality video over the Internet when dealing
with unknown and dynamic:

1. Bandwidth

2. Delay jitter

3. Loss rate

 

B. Scalable video coding (SVC)

Scalable Video Coding (SVC) was standardized as an extension
of H.264/AVC. Conceptually, the design of H.264/AVC covers a Video Coding Layer
(VCL) and a Network Abstraction Layer (NAL). While the VCL creates a coded
representation of the source content, the NAL formats these data and provides
header information in a way that enables simple and effective customization of
the use of VCL data for a broad variety of systems .

 Fig1.SVC
Architecture1

 

The architecture of the H.264/SVC standard is
particularly designed to increase the codec capabilities while offering a
flexible encoder solution that supports three different scalabilities:
temporal, spatial SNR quality. Video scalability is achieved in the temporal,
spatial, quality (SNR), or any combination of these domains2.

 One example
for using scalability is in saving bandwidth when the same media content is
required to be sent simultaneously at different resolutions to support
heterogeneous devices and networks. A typical SVC stream includes one base layer
and one or several enhancement layers. The SVC is not only a convenient
solution to adapt the data rate for varying bandwidth in the mobile Internet,
but it is also the most promising solution to multicast congestion control.

 

                                                                                                                                         
II.        
STEPS FOR IMplemeNtatioN

The various steps involved in
implementation are

Step1: Encoding Process

a) A YUV video is encoded in
H.264 video file

b) Generation of original NALU
trace file

Step2: NS2 Sender Agent

a) NALU trace file is converted
into NS2 traffic trace file

b) Each record of the file is
read and corresponding number of packets are generated

Step3: NS2 Receiver Agent

a) The frame level trace file
,NS2 traffic trace file, original NALU trace file are used to generate received
NALU file

Step4: Decoding Process

a)The receiver generates in real
time trace of received NALUs

b)The received NALU trace is
processed to produce a YUV file

 

 

Fig2. Architecture  for
implementation

                                                                                                                                                         
III.       
IMplemeNtatioN

A. Simulation Platform

To implement the proposed
architecture examples of H.264/SVC transmissions over IEEE 802.11 is provided.
The test video source, Foreman, used in the simulation is in YUV CIF (352 ×
288) format and comprises 300 frames. JSVM (version 9.19) is used to encode the
video with only temporal scalability enabled. Spruce-0.2.1 is used to calculate
the path capacity. SVEF 1.4 framework is used to provide intermediate between
JVSM and ns2.35 scenario.

 

B. Simulation Parameter

 SIFS (?s)                                                               10

 Time slot (?s)                                                       20

 DIFS (?s)                                                              50

 CWmin                                                                 32

 CWmax                                                                            1024

 Physical header (bits)                                      192

 MAC header (bits)                                           224

 ACK (bits)                                                   
112

 Data rate (Mbps)                                            1

 Basic rate (Mbps)                                           1

 Play-out delay (seconds)                                5

 

                                                                                                                                                                      
IV.       
RESULTS

The simulation is carried out and the video result is evaluated
for two different flow

 1. CBR(Constant Bit Rate)

2. VBR(Variable Bit Rate)

 

A.  Delay

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

     Fig3. Packet end to
end delivery when the packet are send at constant rate

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    Fig4. Packet end to
end delivery when the packet are send at variable rate

B. Average
PSNR Ratio

 

 

CBR

17.0566

VBR

16.8542

 

 

C. Visual
Comparison

 

 

 

Fig 5  Original Foreman video file Frame number 3 and Frame number
23      

 

 

 

Fig 6  Frame number 3 and Frame number
23 for  constant rate

 

 

 

                                                                                                                                                                  
V.        
CONclusioN

 

Sending the packets at constant
bit ratio increased the delay parameter but maintain a desirable PSNR ratio
,when the packets were send at variable rate reduced the delay at the receiver
end but the packet received contained noise and PSNR ratio was reduced. Hence
if the network traffic in the wireless network is less it is desirable to send
the video packets at a constant rate

 

VI.  References

 

1     Chou, P. A. (2007).
Streaming media on demand and live broadcast , in P. A. Chou and M. van der
Schaar (Eds.) Multimedia in IP and Wireless Networks, Academic Press, Burlington,
MA, pp. 453-501

2     Dongchil
Kim and Kwangsue Chung (2012). A Network-Aware Quality Adaptation Scheme for
Device.IEEE Transactions on Consumer Electronics, Vol. 58, No. 2, May 2012

3     Van
der Auwera, G.; David, P. D. & Reisslein, M. (Sept. 2008). Traffic and
quality characterisation of single layer video streams with the H.264/MPEG-4
Advanced Video Coding Standard and Scalable Video Coding extension, IEEE Trans.
on Broadcasting, Vol. 54, No. 3, pp. 698-718.

4      Chou, P. A. (2007). Streaming media on demand
and live broadcast , in P. A. Chou and M. van der Schaar (Eds.) Multimedia in
IP and Wireless Networks, Academic Press, Burlington, MA, pp. 453-501

5    
Andrea
Detti, Giuseppe Bianchi, Claudio Pisa,Francesco Saverio Proto, Pierpaolo Loreti
“SVEF: an Open-Source Experimental Evaluation Framework for H.264 Scalable
Video Streaming”.

6     Amina
Kessentini, Imen Werda, Amine Samet, Mohamed Ali Ben Ayed, Nouri Masmoudi
“H.264/SVC Performance and Encoder Bit-stream Analysis”

 

Fig 7  Frame number 3 and Frame number
23 for  variable rate

 

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