NOTE: Threshold compensates for image sources that have a level of noise in
them. In general, there is always a certain amount of noise in any source
that is produced by an analog method. By applying a threshold, this noise
can effectively be ignored by the PURE3 compression engine, resulting in a
lower transmitted bit rate.
° Chroma check box — The Chroma setting adapts the temporal compression to note
the chroma changes in an image. When enabled, chroma thresholding increases the bit
rate. This setting should be selected for video sources.

Bandwidth Management

1b
1c
1a
Figure 34. Bandwidth Portion of the Advanced Controls Panel
Ä Mode — This drop down box is a set of six modes that apply
different spatial and temporal compression schemes to manage the
encoded image data stream. See “Typical bit rates“ for suggested
mode selections.
NOTE: Two of these control modes are available only from
this panel. Four are also accessible in the Bandwidth
Management controls panel settings panel.
• Manual Frame Drop — In this mode, the spatial image quality is held constant.
However, the bit rate is managed by reducing the number of frames that are
transported. The frame rate is managed by setting a value for the Frame Drop
Percentage (see item û, below).
• Shared Flowrate — This mode is the same as the Peak flow rate but the bit rate
control is applied to the aggregate value for all streams from the encoder, as would
be the case if multiple (maximum 4) Unicast RTP streams are chosen as the data
transport method.
• None — See the Control mode drop-down box in “Bandwidth Management
standard controls panel.“
• Peak Flow — See the Control mode drop-down box in “Bandwidth
Management standard controls panel.“
• PBR-F — See the Control mode drop-down box in “Bandwidth Management
standard controls panel.“
• PBR-F (FD) — See the Control mode drop-down box in “Bandwidth
Management standard controls panel.“
Å Target Bandwidth (Mbps) — This value duplicates the Bit rate control in the
Bandwidth Management controls panel. Enter a value of up to 300.000 Mbps to set
the limit for the total bit rate for all data; image, audio, and audio. This control is not
available when the Control mode is set to either None or Manual Frame Drop.
û Frame Drop Percentage — This is the percentage of frames that are dropped
whenever the manual frame drop is the chosen control mode. See “Typical bit rates“
on the next page to see the estimated bit rates for various video, audio, and error
correction selections.
VN-Matrix 325 Serial Digital Over IP CODEC • Operation 45