This document discusses robust video coding using multiple descriptions. It notes that traditional forward error correction suffers from a "cliff effect" where quality drops sharply past a packet loss threshold. Multiple description coding addresses this by splitting the source signal into multiple descriptions at the encoder. Each description is independently encoded and transmitted. At the decoder, lost descriptions can be recovered to avoid severe quality degradation. Experimental results show multiple description coding provides better quality than without in the presence of packet losses during transmission.

1. Robust video coding via multiple descriptions
Riccardo Bernardini
riccardo.bernardini@uniud.it
June 14, 2018

2. Robust video coding via multiple descriptions
Robust Transmission
The problem
1. Signal encoding
2. Transmission
3. Packet losses
4. Quality degraded
Network
Encoder
Packet 1 Packet 3Packet 2
Packet 1 Packet 3Packet 2
Decoder
1
3
2
4
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3. Robust video coding via multiple descriptions
Off the shelf: FEC
The cliff effect
• Let a FEC be designed for
Ploss = p,
– Good quality up to Ploss = p
– Sharp quality drop for Ploss > p
• If we design the FEC for larger values
of p
– More redundancy needed
Low base quality
• Alternative approach:
add redundancy at the signal level
Ploss
p1 p2 p3
Designed for P loss=p2
Designed for P loss=p1
Designed for P loss=p3
1
Quality
2
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4. Robust video coding via multiple descriptions
Multiple Description Coding
The original signal is “split” into different signals (descriptions)
• Each column is processed with a 3/2 redundant filter bank.
2
2
2
h0
h1
h2
M
H264 enc
H264 enc
H264 enc
N
M
N/2
M
N/2
M
N/2
Frame-Based Multiple-Description Video Coding with Extended Orthogo-
nal Filter Banks,EURASIP Journal on Applied Signal Processing, 2006
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5. Robust video coding via multiple descriptions
Multiple Description Coding (2)
Decoder side
1. At the receiver side lost components are recovered by means of block R
2. The restored data stream is processed with the dual of the analysis filter bank
3. The recovered frames are put back in the decoder to avoid error propagation
2
2
2
g 0
g 2
g 1
M
2
3
1
+
concealed frames
M
N/2
M
N/2
M
N/2
N
H264 dec
H264 dec
H264 dec
R
4
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6. Robust video coding via multiple descriptions
Experimental Results
With MD Without MD
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7. Robust video coding via multiple descriptions
Selected pubblications
• Coding schemes
– R. Bernardini, M. Durigon, R. Rinaldo, A. Vitali, and P. Zontone, “Frame-Based Multiple-
Description Video Coding with Extended Orthogonal Filter Banks,” EURASIP Appl. Sig.
Proc. 2006
– R. Bernardini, M. Durigon, R. Rinaldo, A. Vitali, and P. Zontone, “Robust Transmission
of Video Using Frame-Based Multiple Description,” ST-Journal 2007
– D. Alfonso, R. Bernardini, L. Celetto, R. Rinaldo and P. Zontone, “Multiple Description
for Robust Scalable Video Coding,” ICIP 2009
• Efficient reconstruction algorithms
– R. Bernardini and R. Rinaldo, “Efficient Reconstruction from Frame Based Multiple De-
scriptions,” IEEE T-SP 2005
• Filter design for MD schemes
– R. Bernardini and R. Rinaldo, “Oversampled filter banks from extended perfect recon-
struction filter banks,” IEEE T-SP 2006
– R. Bernardini and R. Rinaldo, “Bounds on error amplification in oversampled filter banks
for robust transmission,” IEEE T-SP 2006
– R. Bernardini, “Time-Variant Unit Norm Tight Frames by Means of Modulated Filter
Banks,” IEEE T-SP 2007
• Bit-allocation
– R. Bernardini, R. Rinaldo et al. “Bit Allocation and Quantizer Optimization in Multiple
Description Coding with Oversampled Filterbanks,” ICIP 2005
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