Ericsson MX8400, Справочное руководство

Страница: 86 / 226

Operating the Multiplexer using nCompass Control
4.5.5.4 Minimum and Maximum Bit rates
4.5.5.4.1 Minimum Bit rate
Configuring the minimum bit rate too high reduces the available bit rate for other
Components in the group.
4.5.5.4.2 Maximum Bit rate
Configuring the maximum bit rate too low downgrades the video quality.
A video component may be excessively noisy. Under these conditions, the
associated Encoder may attempt to command large bit rates in the group and
compromise the picture quality on other video components. To avoid this situation,
set the maximum bit rate according to
Table 4.7.
Table 4.7 Bit rate Requirements Relative to Video Resolution
Encoder Resolution (Pixels)
625 Line Mode 525 Line Mode Max. Bit rate
704 x 576 704 x 480 10.0 Mbps
544 x 576 544 x 480 8.0 Mbps
480 x 576 480 x 480 7.0 Mbps
352 x 576 352 x 480 6.0 Mbps
544 x 288 4.0 Mbps
480 x 288 3.5 Mbps
352 x 288 3.0 Mbps
4.5.5.5 Group Performance
4.5.5.5.1 Defining the Term
The Group Performance provides a performance check on the statistical
multiplexing process. In general, the bigger the Encoder group the more scope for a
better performance figure. A group containing reasonable weighting factors
compared to the group bit rate will also have a better group performance figure.
4.5.5.5.2 Monitoring Group Performance
Group Performance can be monitored on the Activity Viewer via nCompass Control
user interface. The Reflex performance screen shows bit rate and quality plots, and
the group performance meter.
4.5.5.6 Grouping of Encoders by Picture Material
If possible, create a group of Encoders carrying a mix of programme types. This is
likely to create the conditions required to achieve an optimal group.
2/1553-FGC 101 1014 Uen B 4-10