Toward realistic MPEG4 video transmission simulations

Background for MPEG System

影像品質的鑑定 一張數位影像經過影像壓縮等處理後，再和原始數位影像做比較，可以發現兩張有所差異。其差異程度的大小，可用影像信號雜訊比 (Peak Signal to Noise Ratios, PSNR) 做為影像失真量測的工具。 SNR = ) PSNR = 10 log10 MSE = ( 由上式中的MSE為兩張m×m數位影像的均方差 (Mean Square Error, MSE)，表示原始數位影像之(i, j)位置上的像素值。表示經處理後的數位影像之(i, j)位置上的像素值。兩張數位影像經PSNR值計算後的結果值越大，則我們就認為這兩張數位影像越相似。

Traffic Trace File Sender Trace File Receiver Trace File 0 H 29 1 segm at 33 ms 1 I 3036 4 segm at 67 ms 2 P 659 1 segm at 99 ms 3 B 357 1 segm at 132 ms 4 B 374 1 segm at 165 ms 5 P 693 1 segm at 199 ms ………………………………………………………. Sender Trace File 0.033333 id 0 udp 29 0.066666 id 1 udp 1000 0.066666 id 2 udp 1000 0.066666 id 3 udp 1000 0.066666 id 4 udp 36 0.099999 id 5 udp 659 ……………………………………………………….. Receiver Trace File 0.046668 id 0 udp 29 0.124710 id 1 udp 1000 0.169155 id 2 udp 1000 0.213599 id 3 udp 1000 0.214428 id 4 udp 36 0.244215 id 5 udp 659 ………………………………………………………..

Exp 1. Source Sink R1 R2 Exp 2. Source Sink R1 R2 DropTail, Queue Limit = 10 packets Source Sink R1 R2 10 Mb 1ms 0.18 Mb 10 ms 10 Mb 1ms Exp 2. WRED, Queue Limit = 10 packets Green 4/8/0.025 Yellow 2/4/0.05 Red 1/2/0.1 Source Sink R1 R2 10 Mb 1ms 0.18 Mb 10 ms 10 Mb 1ms

Test Movie Sequence Movie : Foreman Format: qcif (176 x 144) Frame number: 400 Compression: MPEG 4 GOP: I B B P BB P BB I BB…… Average rate: ~ 200 kbps Peak rate: ~ 400 kbps Each frame is fragmented into 1000 bytes when delivery

BE 170 171 172 173 174 QoS

Relations among PSNR, the fraction of decodable frames, and loss rate

WRED, Queue Limit = 100 packets Green 60/80/0.025 Yellow 40/60/0.05 10Mbps,1ms 10Mbps,1ms 10Mbps,1ms 1.024 Mbps,1ms S2 R3 D2 R1 R2 S2 WRED, Queue Limit = 100 packets Green 60/80/0.025 Yellow 40/60/0.05 Red 20/40/0.1 D3

Test Movie Sequence Movie : Highway Format: cif (352 x 288) Frame number: 2000 Compression: MPEG 4 GOP: I B B P BB P BB I BB…… Average rate: ~ 412 kbps Peak rate: ~ 1116 kbps Each frame is fragmented into 1000 bytes when delivery

QoS Index Green Yellow Red I P B 1 P+B 2 3 I+P 4 5 I+P+B 6 7 8 9

PSNR Flow 1 Flow 2 Flow 3 The Fraction of Decodable Frames, DT=1.0

PSNR Flow 1 Flow 2 Flow 3 The Fraction of Decodable Frames, DT=0.75

PSNR Flow 1 Flow 2 Flow 3 Loss Rate_all (frame)

PSNR Flow 1 Flow 2 Flow 3 Loss Rate_I (frame)

PSNR Flow 1 Flow 2 Flow 3 Loss Rate_P (frame)

PSNR Flow 1 Flow 2 Flow 3 Loss Rate_B (frame)