systematic lossy error protection based on h.264/avc redundant slices
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Systematic Lossy Error Protection based on H.264/AVC Redundant Slices
Systematic Lossy Error Protection based on H.264/AVC Redundant Slices
Shantanu Rane and BernShantanu Rane and Bernd Girodd Girod
Information Systems Information Systems LaboratoryLaboratorySStanford Universitytanford University
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 2
Error-Resilient Video TransmissionError-Resilient Video Transmission
Channel Error Probability
Vid
eo
Qua
lity
FEC cliff effect
Layered video coding with Priority Encoding Transmission (PET)
Systematic Lossy Error Protection(SLEP) using Wyner-Ziv coding [Rane, Girod, ICIP 2004-05]
Construct Wyner-Ziv codec using H.264/AVC redundant slices
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 3
Systematic lossy source/channel coding
SLEP implementation based on H.264/AVC redundant slices
Simulation results
OutlineOutline
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 4
[Shamai, Verdú, Zamir, 1998]
Enhancing analog image transmission using digital side information
[Pradhan, Ramchandran, 2001] Error-resilient distributed video compression schemes
[Sehgal, Ahuja, 2003-04], [Xu, Xiong, 2004] Systematic lossy source-channel coding of video waveforms
[Aaron, Rane, Girod, 2003-04-05]
Encoder Digital Channel
Decoder
Analog Channel
Wyner-ZivEncoder
Sideinfo
Wyner-ZivDecoder
Digital Channel
Systematic Lossy Source/Channel CodingSystematic Lossy Source/Channel Coding
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 5
“Analog Channel”
S S’
S*
Video EncoderVideo Decoder with Error Concealment
Err
or-P
rone
cha
nnel
Wyner-Ziv Decoder
Coarse Quantizer
Wyner-Ziv Encoder
ReconstructionSlepian-
Wolf Encoder
Slepian-Wolf
Decoder
Side information
SLEP for Video TransmissionSLEP for Video Transmission
Analogous to systematic source/channel coding Error corrected up to a distortion introduced by coarse WZ quantizer,
hence lossy protection [Rane, Aaron, Girod, ICIP 2003]
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 6
Encode Redundant Pic
(Requantize)
Entropy Decoding
SLEP using H.264/AVC Redundant SlicesSLEP using H.264/AVC Redundant Slices
WYNER-ZIV ENCODER WYNER-ZIV DECODER
Err
or-p
rone
Cha
nnel
Decode Redundant Slice
Motion vecs +Coding modes
RSDecoder
Side info
Motion vecs +Coding modes
QP
Recovered motion vectorsfor erroneously received
primary slices
EncodePrimary Pic
Q-1 T-1
MC
H.264/AVC DECODER
+Entropy Decoding
OutputVideo
H.264/AVC ENCODERInputVideo
Encode Redundant Pic
(Requantize)
RSDecoder
Parity slicesQP
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 7
Reed-Solomon Coding Across Video SlicesReed-Solomon Coding Across Video Slices
1 byte in slice
filler byte
parity byte
RS code across slices
Transmit only parity symbols
XX X X X X X X X X X X X Xkn
Erasure Decoding
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 8
Experimental SetupExperimental Setup
Systematic Transmission H.264/AVC primary coded bitstream WZ Codec Redundant slices + Reed-Solomon Slepian-Wolf codec Same slice boundaries for primary and redundant slices GOP structure : I-B-P-B-P-… Unequal WZ protection for B and P frames Previous frame concealment
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 9
2 4 6 8 1031
32
33
34
35
36
% of slices lost
PS
NR
(dB
)
encoder, QP 28, 408 kbps
Resilience using Redundant SlicesResilience using Redundant Slices
0
100
200
300
400
500
600
700
800
900
28 32 36 40 44 48
QP of redundant description
Tot
al b
it-ra
te (
kbps
)
Redundant descriptionPrimary description
Video Quality Total Encoding Rate
QP 48
QP 44
QP 40
QP 36
QP 32
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 10
SLEP based on Redundant Slices (SLEP based on Redundant Slices (ForemanForeman))
Transmit WZ coded version of Transmit WZ coded version of the video signalthe video signal WZ bit-rate ~ 10% of bit-rate of WZ bit-rate ~ 10% of bit-rate of the primary descriptionthe primary description Coarser redundant description Coarser redundant description has stronger error-resilience but has stronger error-resilience but greater quantization mismatchgreater quantization mismatch
Primary (systematic) description @ 408 kbps
with QP 28.0
100
200
300
400
500
600
700
800
900
28 28 32 32 36 36 40 40 44 44 48 48
Transmitted WZ bit-rate
Full redundant bit-rate
Transmitted systematic bit-rate
QP of redundant description
To
tal t
ran
smitt
ed b
it-ra
te (
kbp
s)
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 11
SLEP based on Redundant Slices (SLEP based on Redundant Slices (ForemanForeman))
Video quality for various redundant descriptionsSymbol error probability = 5 x 10-4
20 40 60 80 100
24
26
28
30
32
34
36
Frame number
PS
NR
(d
B)
Encoder reconstruction @ 408 kbps
Error concealment only
FEC
QP36
QP48
QP40
Systematic bit-rate 408 kbps, WZ bit-rate ~ 40 kbpsSymbol error probability = 5 x 10-4
Error-freeError-free35.7 dB35.7 dB
Error concealment onlyError concealment only40 kbps FEC40 kbps FECSLEP with redundant QP = 36SLEP with redundant QP = 36SLEP with redundant QP = 40SLEP with redundant QP = 40SLEP with redundant QP = 48SLEP with redundant QP = 4820.9 dB20.9 dB25.5 dB25.5 dB30.9 dB30.9 dB34.2 dB34.2 dB32.9 dB32.9 dB
S. Rane and B. Girod – SLEP based on H.264/AVC redundant slices – VCIP 2006 13
SummarySummary
SLEP based on H.264/AVC redundant slices support Trade-off between error resilience and quantization mismatch
introduced by redundant description Graceful degradation of received video quality compared to FEC
Recent work– H.264/AVC rate control to modulate QP of redundant
description– SLEP on region-of-interest using Flexible Macroblock
Ordering (FMO)
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