A Robust Luby Transform Encoding Pattern-Aware Symbol Packetization Algorithm for Video Streaming...
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Transcript of A Robust Luby Transform Encoding Pattern-Aware Symbol Packetization Algorithm for Video Streaming...
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A Robust Luby Transform Encoding Pattern-Aware Symbol Packetization Algorithm for Video Streaming Over Wireless Network
Dongju Lee and Hwangjun Song
IEEE TRANSACTIONS ON MULTIMEDIA, VOL. 13, NO. 4, AUGUST 2011
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Outline
•Introduction•LT Encoding Pattern-Aware Symbol
Relationship Analysis•Packetization Algorithm of LT Encoded
Symbols•Performance Analysis•Experimental Results•Conclusion
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Introduction• To minimize the quality degradation of video
streaming service caused by packet losses over wireless network.
• Minimize packet loss effects by reducing the dependency among packets conveying Luby transform encoded symbols.
• The LT decoding success rate can be improved at the receiver by minimizing the effect of a lost packet.
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Introduction
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LT Encoding Pattern-Aware Symbol Relationship Analysis
and the element of have a strong dependency on each other.
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LT Encoding Pattern-Aware Symbol Relationship Analysis• Property1 : The decoding success rate of the
root can be improved by assigning {, 1 } to different packets.
• Property2 : The decoding success rate of the source symbols in can be increased if more symbols of are available.
• Property3 : The decoding success rate of the root can be enhanced by packetizing and the elements of its into the same packet.
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Packetization Algorithm of LT Encoded Symbols•The proposed packetization algorithm is
designed to insert more elements of and into the same packet.
: the subset of are put into the same packet with
: determine the number of elements of that are packetized with min{() , ||} and
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Packetization Algorithm of LT Encoded Symbols• Step 0 : Select the first source symbol as a root.• Step 1 : Select a with in { ,1} of the root that
has not been assigned to any packet until now (if all , 1 are already packetized, go directly to Step 4).
• Step 2 : Put the into the target packet chosen by the following rules (Rule i has a higher priority than Rule (i+1)). If any packet is not chosen by the rules below, go to Step 4.
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Packetization Algorithm of LT Encoded Symbols
▫ Rule 1: If an empty packet exists, choose the packet as the target packet.
▫Rule 2: If the available space at a packet is not less than (e.g., if and elements of can be inserted into the same packet), then choose the packet as the target packet.
▫Rule 3: when and elements of cannot be inserted into the same packet, if is less than and the available space at a packet is not less than , then choose the packet as the target packet with = in order to insert and elements in into the same packet as the best alternative policy of Rule 2
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Packetization Algorithm of LT Encoded Symbols• Step 4 : Sequentially selected next source
symbol as a root and repeat Step 1-3 with new root and the initial until no more root exist, go to Step 5.
• Step 5 : Randomly distribute the remaining encoded symbols into residual spaces of the packets.
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Packetization Algorithm of LT Encoded Symbols• Step 3: Determine a by randomly choosing
elements in . Put into the target packet as shown in Fig. 3.
• Step 4: Select source symbol sequentially as a root and repeat Step 1–3 with the new root and the initial until no more root exit, go to Step 5.
• Step 5: Randomly distribute the remaining encoded symbols into the residual spaces of the packets.
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Performance Analysis• Performance measure : The number of the
successfully received elements of with .• Claim : || > ||
: the number of transmitted packets (> ): the number of encoded symbols the average number of symbols in the target packet when the remaining symbols are randomly allocated to packet.
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Performance Analysis• To guarantee || > ||: > - (4)• Combining (3) and (4) > (5) then, = , for (6) (7)
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Experimental Results-setup
• Implemented by using Java and C/C++.
• H.264/AVC JM Software is used as a video codec.
• Test video sequences : Harbour and Soccer of CIF size and 15 fps.
• The GOP structure is set to include one I-frame and 29 P-frames.
• Every simulation is repeated 1000 times and averaging values of
the repeated simulations
• LT codes : robust soliton distribution and two parameters of this
degree probability distribution are set to 0.03 and 0.5,
respectively
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Performance Verification of the Proposed Packetization Algorithm
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Performance Verification of the Proposed Packetization Algorithm
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Performance Verification of the Proposed Packetization Algorithm
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Perf
orm
ance
Veri
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f th
e P
rop
ose
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ack
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Alg
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Video Quality Comparison When Packet Loss Pattern Is Random
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Video Quality Comparison When Packet Loss Pattern Is Random
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Video Quality Comparison When Packet Loss Pattern Is Random
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Video Quality Comparison When Packet Loss Pattern Is Burst
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Video Quality Comparison When Packet Loss Pattern Is Burst
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Video Quality Comparison When Packet Loss Pattern Is Burst
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Video Quality Comparison When Packet Loss Pattern Is Burst
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Video Quality Comparison When Packet Loss Pattern Is Burst
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Conclusion• An efficient LT encoding pattern-aware
packetization algorithm for LT encoded symbols to provide a robust video streaming service over error-prone wireless network.
• The basic concept of the proposed packetization algorithm may be extended to other fountain codes with some modifications.