SHEAU-RU TONG Management Information System Dept., National Pingtung University of Science and...
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APPLICATION-LAYER ERROR RESILIENCE FOR WIRELESS IP- BASED VIDEO BROADCASTING SHEAU-RU TONG Management Information System Dept., National Pingtung University of Science and Technology, Taiwan (R.O.C.) [email protected]YUAN-TSE YU Dept. of Software Engineering National Kaohsiung Normal University, Taiwan (R.O.C.) [email protected]
SHEAU-RU TONG Management Information System Dept., National Pingtung University of Science and Technology, Taiwan (R.O.C.) [email protected] YUAN-TSE
SHEAU-RU TONG Management Information System Dept., National
Pingtung University of Science and Technology, Taiwan (R.O.C.)
[email protected] YUAN-TSE YU Dept. of Software Engineering
National Kaohsiung Normal University, Taiwan (R.O.C.)
[email protected] 1
Multi-path fading and fast interference in wireless networks
causes heavy packet loss burst and poor video broadcast quality.
Low-layer forward error coding (FEC) is suitable for fixing
short-term loss burst, but not for long- term loss burst. 3
Slide 5
A HSDPA traffic trace (with link-layer FEC) of a moving vehicle
where multiple-packet-loss events frequently occur. 4
Slide 6
Multiple descriptor coding (MDC): Split a video stream into
several sub-streams (descriptors) Encode each sub-stream
independently and transmit them over different data paths.
Exploiting path diversity. Protecting key-frame is more efficient!
5 Application-layer error resilience is desirable!
Slide 7
Basic idea: logically applying MDC in the application layer
with two new features. Replicate key-frames Interleave multiple
descriptors over an IP multicast channel. Advantages: Distributing
long loss burst over multiple descriptors to mitigate the damage
impact. Exploiting time diversity of key frame transmission. 6
Slide 8
The system architecture of RMD 7
Slide 9
Frame replication/insertion b: the number of replicas. s: the
number of the frame slots shifted. 8
Slide 10
Analysis of RMD Frame slot time (I sub-stream ) where k is
number of sub-streams, r video data rate and p GOP size. Delay (D)
and buffer space (B) where S I and S O are the maximum frame size
of I frames and the other frames, respectively. 9
Slide 11
Key frame error probability (P kf_err ) where is the packet
slot error rate, g is the number of packets for an I frame. 10 P
kf_err with respect to various bs when k=4 and g=4.
Slide 12
Simulation configurations 400 frames MPEG-4 with a QCIF format.
30 fps with GOP pattern of IPPPPPP. Packet size of 1024 bytes
Comparing RMD with Single Descriptor (SD) Multiple Descriptors (MD)
SD/FEC(255, 159) MD/FEC(255, 159) 11
Slide 13
12 When the packet loss rate increases beyond 15%, RMD starts
to outperform SD/FEC or MD/FEC (PSNR>21dB).
Slide 14
13 The instances of PSNR with respect to various schemes when
packet loss rate = 20%. RMD protects the key frame better!
Slide 15
14 Average PSNR of RMD with respect to various ses when b=3.
Average PSNR of RMD with respect to various ses when b=2. Impact of
b and s in RMD The PSNR curve is improved (leveraged) as s and b
increases. The improvement is magnified under a heavy packet loss
condition (15%-35%)
Slide 16
Redundancy cost ( =20%) RMD (b=3) has a redundancy ratio
slightly higher than that of MD/FEC, but can gain a PSNR about 5
dB. 15
Slide 17
RMD is an ideal application layer approach for combating
excessive burst errors and protecting key frames. RMD (b=3) has a
redundancy ratio slightly higher than that of MD/FEC, but can gain
a PSNR about 5 dB subject to =20%. How to co-work RMD with other
adaptive FEC to offer a full spectrum of protection against various
burst errors is worthy of further study. 16