Upload
others
View
4
Download
0
Embed Size (px)
Citation preview
Video transmission over high-speed WPAN’s based onlow-power data compression
Eugeniy Belyaev1, Andrey Turlikov1 and Anna Ukhanova2
1State University of Aerospace Instrumentation, Saint-Petersburg2DTU Fotonik, Technical University of Denmark
November 4, 2009
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 1 / 21
Video transmission over high-speed WPAN’s 1 2 3
HDTV1920x1080, 60 frames/s
IEEE 802.15.3c
System properties:I Transmission rate up to 6Gbps;I Low-power data transmitter.
1http://www.ieee802.org/15/pub/TG3c.html2http://www.wirelesshd.org/3http://wirelessgigabitalliance.org/Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 2 / 21
System restrictions and requirements
System restrictions:I Low-memory and low-complexity video processing;I One-pass processing only is possible;
System requirements:I Very low transmission latency (1-3 ms);I Continuous video playback at the receiver;I Acceptable visual quality for wide types of video sources:
F sequences of computer graphics, snapshots;F natural and mixed images.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 3 / 21
Possible solutions
Uncompressed video transmission1;Intra single-layer video coding2;Intra scalable video coding3;Distributive video coding4.
1H. Singh, Jisung Oh, Changyeul Kweon, Xiangping Qin, Huai-Rong Shao and ChiuNgo, “A 60 GHz wireless network for enabling uncompressed videocommunication“, IEEE Communications Magazine, 2008
2E. Belyaev, A. Dogadaev and A. Ukhanova. “MINMAX rate control in near-losslessvideo encoders for real-time data transmission“, XII International Symposium onProblems of Redundancy in Information and Control Systems, 2009.
3M.Gallant and F. Kossentini, “Rate-distortion optimized layered coding with unequalerror protection for robust Internet video“, IEEE Transactions on Circuits and Systemsfor Video Technology, 2001.
4T. Kuganeswaran, X. Fernando, L. Guan, “Distributed video coding andtransmission over wireless fading channel“, Canadian Conference on Electrical andComputer Engineering, 2008.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 4 / 21
Possible solutions comparison
Solution Encodercomplexity
Decodercomplexity
Compressionefficiency
Link/PHYlayers mod-ification
Uncompressedvideo transmission
very low very low very low yes
Intra single-layervideo coding
low low medium no
Intra scalable videocoding
medium medium low partly
Distributive videocoding
low high high yes
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 5 / 21
AgendaIntra single-layer video compression and transmission over high-speed WPAN’s
H.264/AVC low-complexity single-layer video compression;Video transmission system description
I End-to-end distortion in video transmission system;I End-to-end latency in video transmission system;I MINMAX optimization task description.
Main idea of the video source rate control;Video transmission system model;Practical results;Future work.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 6 / 21
H.264/AVC low-complexity single-layer video compression
Inputframe
Video sourcerate control
DCT 4x4 Quantization EncoderBuffer Channel
Number of bits
Channel info
InverseQuantization
Inverse DCT4x4
IntraDC-prediction
QP/Skip
CAVLC NAL
IPCM / Intramode decision
Hash valuecalculation
Low-memory INTRA solution (32 pixel lines);DC-Prediction only, 4x4 DCT only, CAVLC;Hash function calculation for temporal redundancy removal (by usingSKIP macroblock type);
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 7 / 21
Proposed video transmission system scheme
Encoder buffer
Video sourcerate control Channel
Decoder buffer
Videoencoder
Videodecoder
Input macroblocksequence
Reconstructedmacroblock sequence
eT∆
dT∆
ebT∆
dbT∆
cT∆
End-to-endlatency
dT∆
)(tbtq
),( tqtmr
tm
Channelrate control
Transmitter
Receiver
Channelfeedback
Coderate
Modulationtype
1−tc
Packetsize
tbT∆
rbT∆
End-to-enddistortion
ARQ
Quantizationdistortion
Channeldistortion
Channel rate controller chooses the transmission scheme thatmaximizes the channel throughput;Video source rate controller chooses the quantization step qt andmacroblocks type mt ∈ {intra, skip} to provide acceptable visualquality and continuous video playback for given channel throughput.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 8 / 21
End-to-end distortion in video transmission system
The end-to-end distortion dt for unit t:dt = d(qt) + dc ,
d(qt) is quantization distortion, dc is distortion caused by channel errors.
MINMAX quality criteria1:minimize max
tdt .
Packet loss probability for ARQ with n retransmissions:pnt = (1− (1− BER)l )n,
BER is bit error rate, l is packet length.
If BER < 10−4 then l and n can be chosen to guarantee that pnt < 10−10.
Therefore, for further optimization we can disregard packet losses andminimize d(qt) only.
1N. Cherniavsky, G. Shavit, M.F. Ringenburg, R.E. Ladner, E.A. Riskin,“Multistage:A MINMAX bit allocation algorithm for video coders“, IEEE Transactions on Circuitsand Systems for Video Technology, 2007.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 9 / 21
Bit error rate in IEEE 802.15.3c1
-6
-5
-4
-3
-2
-1
00 2 4 6 8 10 12 14 16 18 20 22 24
SNR [dB]
BER
SQPSK, 1/2 2QPSK, 1/2 16QAM, 1/2
16QAM, 3/4 64QAM, 1/2 2QPSK, 3/4
10
10
10
10
10
10
10
BER<10-4
1IEEE 802.15 WPAN Millimeter Wave Alternative PHY Task Group 3c (TG3c),Contributions and documents, 2009.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 10 / 21
End-to-end latency in video transmission systemThe number of bits in the encoder buffer after compression unit t:
be(t) = max{0, be(t − 1)− ct}+ rt(qt , mt),ct is number of bits that are transmitted during compression of the unit t,rt(qt , mt) is bit size of the compressed unit t.Assume that data on the receiver side is accumulated for some time L afterwhich the decoding and playing starts.
End-to-end latency ∆T = L, if the number of bits in the encoder buffer1 is
be(t) ≤ beff (t) =t+L·f ·N∑i=t+1
ci ,
where beff (t) is the effective buffer size2, N is a number of units in theframe and f is a frame rate.
1A.R. Reibman and B.G Haskell, “Constraints on variable bit-rate video for ATMnetworks“, IEEE Transactions on Circuits and Systems for Video Technology, 1992.
2A. Ortega and M. Khansari, “Rate control for video coding over variable bit ratechannels with applications to wireless transmission“, International Conference on ImageProcessing, 1995.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 11 / 21
MINMAX optimization task description
For high-speed video transmission we can use high-resolution quantizationhypothesis1 that defines distortion as d(q) = q2/12, therefore MINMAXcriteria corresponds to
minimize maxt
qt . (1)
Let us formulate rate control optimization task according to the latencyrequirements and the MINMAX quality criteria. For each unit t it isnecessary to choose the quantization step qt , so that{
minimize maxt
qt
be(t) ≤ beff (t).(2)
1H. Radha, M. Dai, D. Loguinov, “Rate-distortion modeling of scalable videocoders“, International Conference on Image Processing, 2004.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 12 / 21
Video source rate control
MINMAXoptimization task
Multi-pass optimal solutionby consecutive search
One-pass real-timevideo source rate control
qqt~= qqqt ∆+<~
for eachunit t
after adaptation,for each unit t
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 13 / 21
Solution of MINMAX task by consecutive search algorithm
t0
1
2)()(tbtb
eff
e
1q
2q3q
Theorem 1. Consider q̃ the MINMAX solution found by the consecutivesearch algorithm. There is no sequence of quantization steps y1, y2, . . . forwhich max
tyt < q̃ that does not lead to the transmitter buffer overflow.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 14 / 21
One-pass MINMAX video source rate control algorithm
BufferAccumulation
LatencyRestoration
skipped isunit )()( tbtb eff
e >
skipped isunit restorednot islatency if
t
effe
qtbtb
withcompressed isunit )()( ≤
)0(0 qq =begin
t
tt
qqqq
withcomressed isunit
restored islatency if+∆+←
Theorem 2. Consider that consecutive search algorithm finds thequantization step value q̃. Then for the proposed algorithm with initialvalue q0 ≤ q̃, the inequality qt < q̃ + ∆q+ holds true for any timemoment t.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 15 / 21
System model1
Encoder buffer
Video sourcerate control
Decoder buffer
Videoencoder
Videodecoder
Input macroblocksequence
Reconstructedmacroblock sequence
eT∆
dT∆
ebT∆
dbT∆
End-to-endlatency
End-to-enddistortion
dT∆
)(tebtq
),( tqtmr
tm
1−tc
SNR time variancemodel
SNR / Throughputmodel
tSNR
Channeltc
1S. Collonge, G. Zaharia, G. El Zein, “Influence of the human activity on wide-bandcharacteristics of the 60GHz indoor radio channel“, IEEE Transactions on WirelessCommunications, vol.3, pp. 2396–2406, 2004
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 16 / 21
SNR/Throughput dependence for different MCS1
0
1000
2000
3000
4000
5000
6000
0 2 4 6 8 10 12 14 16 18 20 22 24
SNR [dB]
Thro
ughp
ut [m
bps]
SQPSK, 1/22QPSK, 1/216QAM, 1/216QAM, 3/464QAM, 1/22QPSK, 3/4Best
1IEEE 802.15 WPAN Millimeter Wave Alternative PHY Task Group 3c (TG3c),Contributions and documents, 2009.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 17 / 21
Test video sequences
Breeze Desktop
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 18 / 21
Practical results for Breeze
0500
10001500200025003000
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5time [sec]
Rate
[Mbp
s]
Channel rateVideo source rate
10203040506070
0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450frame number
RGB-
PSNR
[dB]
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 19 / 21
Practical results for Desktop
0500
10001500200025003000
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5time [sec]
Rate
[Mbp
s]
10203040506070
0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450frame number
RGB-
PSNR
[dB]
Channel rate
Video source rate
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 20 / 21
Future work
It is interesting to solve the same optimization task for others videoprocessing approaches and compare it with intra single-layer videocompression approach.
Eugeniy Belyaev (SUAI) Video transmission over WPAN’s November 4, 2009 21 / 21