Running GStreamer Applications

Running GStreamer Applications — How to run and debug your GStreamer application

Running and debugging GStreamer Applications

Environment variables

GStreamer inspects a few of environment variables in addition to standard variables like LANG, PATH or HOME.

GST_PLUGIN_SYSTEM_PATH This environment variable can be set to a colon-separated list of paths. If this variable is not set, GStreamer will fill in this list for you with

  • plug-ins in the user's home directory. These are stored in a directory called plugins inside the .gstreamer-0.10 directory in the user's home directory.

  • plug-ins installed system-wide. On this system, they are stored in /usr/local/lib/gstreamer-0.10.

GStreamer will scan these paths for GStreamer plug-ins. These plug-ins will be loaded after the plug-ins in the GST_PLUGIN_PATH variable below. The paths are scanned in the given order. This allows a user to override system-installed plug-ins with his own versions. Setting this variable to an empty string will cause GStreamer not to scan any system paths at all for plug-ins. This can be useful if you're running uninstalled (for development purposes) or while running testsuites.

GST_PLUGIN_PATH This environment variable can be set to a colon-separated list of paths. GStreamer will scan these paths for GStreamer plug-ins. These plug-ins will be loaded in addition to, and before, the plug-ins in the system paths.

GST_DEBUG If GStreamer has been configured with --enable-gst-debug=yes, this variable can be set to a list of debug options, which cause GStreamer to print out different types of debugging information to stderr. The variable takes a comma-separated list of "category_name:level" pairs to set specific levels for the individual categories. The level value ranges from 0 (nothing) to 5 (LOG).

1 - ERROR

Logs all fatal errors. These are errors that do not allow the core or elements to perform the requested action. The application can still recover if programmed to handle the conditions that triggered the error.

2 - WARNING

Logs all warnings. Typically these are non-fatal, but user-visible problems are expected to happen.

3 - INFO

Logs all informational messages. These are typically used for events in the system that only happen once, or are important and rare enough to be logged at this level.

4 - DEBUG

Logs all debug messages. These are general debug messages for events that happen only a limited number of times during an object's lifetime; these include setup, teardown, change of parameters, ...

5 - LOG

Logs all log messages. These are messages for events that happen repeatedly during an object's lifetime; these include streaming and steady-state conditions.

The category_name can contain "*" as a wildcard. For example, setting GST_DEBUG to GST_AUTOPLUG:5,GST_ELEMENT_*:3, will cause the GST_AUTOPLUG category to be logged at full LOG level, while all categories starting with GST_ELEMENT_ will be logged at INFO level. To get all possible debug output, set GST_DEBUG to *:5

GST_DEBUG_NO_COLOR Set this environment variable to any value ("1" typically) to switch off colouring in GST_DEBUG output. This has the same effect as specifying the --gst-debug-no-color command line option to well-behaved GStreamer applications (ie. those that pass command-line options correctly to GStreamer). This is particularly useful to reduce the size of debug output and also allows for the output to be compressed much better than with colours turned on.

GST_REGISTRY_FORK Set this environment variable to "no" to prevent GStreamer from forking on startup in order to update the plugin registry. This is useful for debugging purposes, but should not be used under normal circumstances, since it means that plugins may be loaded into memory even if they are not needed by the application.