TITRE Adaptive Packet Video Streaming Over IP Networks - LaBRI
TITRE Adaptive Packet Video Streaming Over IP Networks - LaBRI
TITRE Adaptive Packet Video Streaming Over IP Networks - LaBRI
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object is composed of three Layers: BL, EL1 and EL2. The throughputs of the different layers are<br />
shown in Figure 4-28 (c). <strong>Video</strong> object 3 has an average throughput of 124 Kbit/s and a peak rate<br />
of 356 Kbit/s. It is composed of one single layer (see Figure 4-28 (c)).<br />
3000<br />
2500<br />
Full MPEG Scene<br />
1000<br />
VO1 BL<br />
VO1 EL1<br />
VO1 EL2<br />
800<br />
Throughput (Kbits)<br />
2000<br />
1500<br />
1000<br />
Throughput (Kbits)<br />
600<br />
400<br />
500<br />
200<br />
0<br />
0 20 40 60 80 100 120<br />
time (s)<br />
(a)<br />
0<br />
0 20 40 60 80 100 120<br />
time (s)<br />
(b)<br />
1000<br />
VO2 BL<br />
VO2 EL1<br />
VO2 EL2<br />
1000<br />
VO3<br />
800<br />
800<br />
Throughput (Kbits)<br />
600<br />
400<br />
Throughput (Kbits)<br />
600<br />
400<br />
200<br />
200<br />
0<br />
0 20 40 60 80 100 120<br />
time (s)<br />
0<br />
0 20 40 60 80 100 120<br />
time (s)<br />
(c)<br />
(d)<br />
Figure 4-28: Instantaneous throughput of the different MPEG-4 <strong>Video</strong> Object<br />
4.3.3.2 Simulation Results<br />
We perform an intensive simulation, each time with different parameters to see the behavior<br />
of our video on demand system. We vary the number n of FTP source according to following<br />
scenarios: (1) Scenario A: one FTP source; (2) Scenario B: two FTP sources; (3) Scenario C: four<br />
FTP sources; (4) Scenario D: eight FTP sources. FTP sources send data from time t=30s until<br />
time= 90s.<br />
This section presents some QoS measurement such as, the video server throughput as a<br />
function of network state, packet loss and end-to-end packet transmission delay.<br />
4.3.3.2.1 Network Performance<br />
4.3.3.2.1.1 <strong>Video</strong> Server Throughput<br />
The video server regulates its transmission rate to reflect the allowed rate by adding or<br />
dropping audio-visual entities. Results obtained of the different scenarios are shown in Figures<br />
below. Also, to simplify the interpretation of the results, Table 4-6 summarizes the transmission<br />
ratio per AVO stream observed during the period of the simulations (120s). Note that the FTP<br />
sources begin data transmission at time t=30s, and stop at time t=90s. VO3 has the low ratio since<br />
it has the lowest priority score is the scene. VO1 and VO2 have the same priority score, so the<br />
corresponding layers have more or less the same transmission ratio.<br />
98
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