Gstreamer Debug

To enable debug output, set the GST_DEBUG environment variable to the desired debug level. All levels below that will also be shown (i.e., if you set GST_DEBUG=2, you will get both ERROR and WARNING messages).

Furthermore, each plugin or part of the GStreamer defines its own category, so you can specify a debug level for each individual category. For example, GST_DEBUG=2,audiotestsrc:6, will use Debug Level 6 for the audiotestsrc element, and 2 for all the others.

export GST_DEBUG=<some element name>:<1-6?>,<some otherelement>:<1-6>

如果不太清楚问题出在哪儿，就启用 debug

export GST_DEBUG=*:3 

Debug Level

#	Name	Description
0	none	No debug information is output.
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	FIXME	Logs all “fixme” messages. Those typically that a codepath that
		is known to be incomplete has been triggered. It may work in
		most cases, but may cause problems in specific instances.
4	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.
5	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, etc.
6	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. This is used for log
		messages that happen on every buffer in an element for example.
7	TRACE	Logs all trace messages. Those are message that happen very
		very often. This is for example is each time the reference
		count of a GstMiniObject, such as a GstBuffer or GstEvent, is
		modified.
9	MEMDUMP	Logs all memory dump messages. This is the heaviest logging and
		may include dumping the content of blocks of memory.
+——————————————————————————+

Conclusion

• How to get more debug information from GStreamer

  • using the GST_DEBUG environment variable.

• How to print your own debug information into the GStreamer log?

• with the GST_ERROR() macro and relatives.

• How to get pipeline graphs?

• with the GST_DEBUG_DUMP_DOT_DIR environment variable.