53
utILIzatIon graph
The top section contains a graph of the outgoing (or incoming) utilization of the network. The bars
indicate the average data rate used by the system during each one second window. It is expected that
the size of these bars will vary due to a variety of factors including:
1
H.264
video is a variable bitrate system, and source material will affect the data
rate. Static, simple images require much less network throughput that complex,
moving images.
2
CrossLock has control over data rate through a technique called “
throttling
”.
Based on network feedback statistics, CrossLock will reduce and increase the
utilization dynamically.
If more than one network device is in use, the utilization graph will be color coded, indicating the
relative utilization of each network device. This is illustrated in
Figure 28
. The color code key for each
network device appears on the right side of the graph.
Overlayed on the network utilization graph are two colored lines:
1
Encoder target
- This reflects the bitrate chosen in the profile used in the
connection. This is treated as a maximum value, so utilization should mostly
remain below this line. Because these values are averaged, there may be
moments where the utilization moves above the target line momentarily.
2
Throttle rate
- When CrossLock throttling is enabled (the default state) this line
indicates how much throttling will be applied. You will see utilization stay mostly
below the throttling line. On stream startup on a new CrossLock connection,
throttling will tend to be more aggressive until the system finds a good throttling
level (usually within 30 seconds).
packet Loss graph
The bottom graph indicates, in percentage terms, what’s gone wrong on the network during each
one-second window. Three different color-coded entries appear here:
1
Packet Loss (dark red)
- The system has detected a packet has been completely
dropped by the network and was never received by the decoder.
2
Packet Late (bright red)
- The system received the packet, but it was too late for
decoding and playout.
3
Packet recovered (green)
- The packet was either lost or late, but was recovered
either by the
Forward Error Correction (FEC)
or
Automatic Repeat Query (ARQ)
error correction built into CrossLock.
