systematic lossy forward error protection for video waveforms
DESCRIPTION
Systematic Lossy Forward Error Protection for Video Waveforms. Overview. Error Resilient Digital Video Broadcasting Systematic Lossy Forward Error Protection Embedded Wyner-Ziv Coding Improved Wyner-Ziv Video Codec. uplink. Satellite Broadcast. Terrestrial broadcast. Cable TV. - PowerPoint PPT PresentationTRANSCRIPT
1
Department of Electrical Engineering,Stanford University
Anne Aaron, Shantanu Rane, David Rebollo-Monedero and Bernd Girod
Systematic Lossy Forward Error Protection
for Video Waveforms
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 2
Overview
Error Resilient Digital Video Broadcasting Systematic Lossy Forward Error Protection Embedded Wyner-Ziv Coding Improved Wyner-Ziv Video Codec
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 3
Error-Resilient Digital Video Broadcasting
Terrestrial broadcast
Cable TV
Satellite Broadcast
uplin
k
• Forward Error Correction (FEC) “Cliff” effect For graceful degradation,
Priority Encoding Transmission (PET) [Albanese, et al., 1996]
Layered representation incurs a rate-distortion penalty
• Forward Error Protection (FEP) Protects the video waveform Graceful degradation without
layered representation
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 4
Encoder
Related Work
Channel A
DecoderChannel DX X*
Y
• Bounds for systematic lossy source-channel coding
[Shamai, Verdu and Zamir, 1998]
• Enhancing analog transmission systems using digital side information [Pradhan and Ramchandran, 2001]
• Robust predictive coding [Sehgal and Ahuja, 2003]
Side information
uncoded
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 5
S*Reconstructio
n
Slepian-Wolf
Encoder
Slepian-Wolf
Decoder
Side information
Coarse Quantizer
Scalar Quantizer
Turbo Encoder
Turbo Decoder
Systematic Lossy Forward Error Protection
MPEG Encoder
MPEG Decoder with Error
Concealment
Err
or-P
rone
cha
nnelS S’
Protects the original video waveform “Lossy” protection
Wyner-Ziv Decoder
Wyner-Ziv Encoder
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 6
Results
Carphone: CIF, 50 frames @ 30fps 1 Mbps, 1% macroblock loss
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 7
Error Concealment only (No WZ bits)
Wyner-Ziv Coding (16 quantization levels, 0.75bpp)
Carphone: CIF, 1 Mbps, 1% macroblock loss
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 8
Embedded Wyner-Ziv Codec
MPEG Encoder
MPEG Decoder with Error
Concealment
Err
or-P
rone
cha
nnelS S’
S*Wyner-ZivEncoder A
Wyner-ZivDecoder A
S**Wyner-ZivEncoder B
Wyner-ZivDecoder B
• Graceful degradation of video quality• Does not require layered representation
… …
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 9
Results2-level Wyner-Ziv Codec
Carphone: CIF, 50 frames @ 30fps 1 Mbps, 1% macroblock loss
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 10
Systematic Lossy Forward Error Protection
MPEG Encoder
MPEG Decoder with Error
Concealment
Err
or-P
rone
cha
nnelS S’
Wyner-Ziv Decoder
Coarse Quantizer
Wyner-Ziv Encoder
Reconstruction
Slepian-Wolf
Encoder
Slepian-Wolf
Decoder
S*
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 11
Improved Wyner-Ziv Coder
Err
or-P
rone
cha
nnelMPEG
Encoder
MPEG Decoder with Error
ConcealmentS S’
MPEGEncoder
Common reference frame
MPEGEncoder
[Rane, Aaron, Girod (submitted to VCIP ’04)]
Parity symbols
R-SEncoder
R-SDecoder
Side information
S*
Wyner-Ziv Encoder
Wyner-Ziv Decoder
MPEGDecoder
Common reference frame
Fallback to coarse representation
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 12
Systematic Lossy FEP vs. FEC Foreman.cif
FECMain Stream @ 1.092 MbpsFEC (n,k) = (40,36) FEC bitrate = 120 KbpsTotal = 1.2 Mbps
Proposed SchemeMain Stream @ 1.092 MbpsWZ Stream @ 270 KbpsFEP (n,k) = (52,36)WZ bitrate = 120 KbpsTotal = 1.2 Mbps
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 13
1 Mbps + 120 kbps FEC(33.03 db)
Foreman: CIF, 50 frames, symbol error rate = 10-3
1 Mbps + 120 kbps FEP(38.40 db)
Aaron, Rane, Rebollo-Monedero, Girod: Forward Error Protection of Video Sept. 15, 2003 14
Summary
• A novel systematic lossy forward error protection scheme for error-resilient video broadcasting
• Wyner-Ziv coding applied to forward error protection• Advantages
More robust than FEC over a wide range of error ratesGraceful degradation without layered video representationBackward-compatible