Intelligent Roadway Information System
A flow stream is a video stream which is not provided directly by a camera, but by a streambed server. They can be used to transcode from one video encoding to another, overlay text, or rebroadcast a unicast RTSP stream to a multicast address (with RTP).
Streambed can run on one or more dedicated computers, and is controlled by IRIS
streambed protocol. A controller and associated comm link
must exist for each streambed server. Each flow stream must be assigned to an
IO pin on a streambed controller.
View ➔ Video ➔ Flow Streams menu item
|Flow stream||Flow stream name|
|Restricted||Flag restricting flow to only published cameras|
|Location overlay||Flag indicating whether camera location should be added|
|Quality||Encoder stream quality|
|Camera||Source Camera name|
|Monitor num||Source Video monitor number|
A camera can be used as the source of a flow stream. The
should be configured, but
monitor num must be blank.
With a camera source, the sink is normally defined by the camera's encoder
type. It must contain a stream with
flow stream checked and a
that matches the flow stream.
If the sink encoding is different than the source encoding, the flow stream will be transcoded. Warning: this requires more CPU time than simply rebroadcasting.
The camera sink uses RTP, sent to the camera's multicast address with the stream's multicast port.
Video Monitor Source
A video monitor can be used as a flow stream source — more precisely, what's
being displayed on that monitor. The
monitor num field should be configured,
camera must be blank.
The source is defined by the current camera displayed on the specified monitor
number. That camera's encoder type must contain a stream with the same
quality value. If multiple streams match, the one with
flow stream checked
For either type of source, if
port are specified, they define a
static sink, using RTP.
A static sink encoding is:
- same as the source encoding for a camera source
- h.264 for a video monitor source