SmallNetBuilder

Packet Loss Sensitivity - Streaming

So with these test files in hand, I then both streamed and played them while trying different packet loss settings in the Linktropy 4500. I started out with a 1% packet loss rate with a streamed file and found blockiness right of the bat. I then ran a series of tests summarized in Tables 1 through 3 below. You'll have to forgive the use of subjective descriptions in the results, but it was the best way that I could characterize what I found.

I've also included some screen captures of error rates, so that you can get a feel for what I was seeing.

Table 1: VOB file stream results

Figure 10: Streamed VOB file with 5% packet loss (image © Disney, click to enlarge)

Table 2: DivX file stream results

Figure 11: Streamed DivX file with 1% packet loss (image © Sony Pictures, click to enlarge)

Table 3: PSP / MPEG4 file stream results

Figure 12 shows a particularly nasty glitch encountered with a 0.05% packet loss. So even when the glitches were infrequent, they could still be pretty nasty!

Figure 12: Streamed PSP/MPEG4 file with 0.05% packet loss (image © Disney)

My general conclusions from the streaming tests are:

• it doesn't take much packet loss to introduce problems into streamed video
• bit rate and encoding format don't make much difference in a stream's ability to compensate for packet loss errors