GstInterpipe - Dynamic Switching
 | Open-source project from RidgeRun. |
This page contains a detailed description of the GstInterpipe Dynamic Switching feature.
One of the greatest strengths of GstInterpipe is the ability of an interpipesrc to switch between different interpipesinks at runtime. To do so, change the listen-to property. Similarly, disconnections and reconnections can be performed by clearing and setting the property accordingly. When performing dynamic switching, caps must be taken into consideration. Specifically, a switch can be performed to a node in two scenarios:
- No other listeners
- Caps are re-negotiated between the two pipelines, looking for the optimum caps.
- Existing listeners
- The sink pipeline must support the caps already configured by the node and listeners, otherwise, it'll fail.
The following figure illustrates this concept:
The caps re-negotiation capability can be disabled with the allow-renegotiation property. The following table summarizes the involved property:
| Property | |
|---|---|
| Element | interpipesrc |
| Name | allow-renegotiation |
| Description | Allow the interpipesrc to renegotiate caps when attached to an interpipesink with different caps |
| Special Values | |
The switch can be disabled entirely by setting the block-switch property. The following table summarizes the involved property:
| Property | |
|---|---|
| Element | interpipesrc |
| Name | block-switch |
| Description | Allow changing the node a listener is currently listening to |
| Special Values | |
Programatically, the dynamic switch can be performed as the following:
/* Create pipelines */
GstElement *pipe1 = gst_parse_launch ("videotestsrc ! interpipesink name=camera1", NULL);
GstElement *pipe2 = gst_parse_launch ("videotestsrc ! interpipesink name=camera2", NULL);
GstElement *pipe3 = gst_parse_launch ("interpipesrc name=src listen-to=camera1 ! fakesink", NULL);
/* Grab a reference to the interpipesrc */
GstElement *src = gst_bin_get_by_name(pipe3, "src");
/* Perform the switch */
g_object_set (src, "listen-to", "camera2", NULL);