How do I view gstreamer debug output?

How to view the output of functions like GST_CAT_INFO, GST_DEBUG etc? Do I need to compile gstreamer myself with debug level set or it can be done at application level?

0

6 Answers

Debugging messages can be printed in stderr by using the GST_DEBUG environment variable (if gstreamer has been compiled with --enable-gst-debug, which is default).

For example: GST_DEBUG=audiotestsrc:5 gst-launch audiotestsrc ! fakesink will log everything (5) from the audiotestsrc element.

You can change your program debugging output at runtime using setenv("GST_DEBUG","cat:level...", 1)

Sometime reading GStreamer debugging can be tedious. You can give gst-debug-viewer a try.

You can read the Documentation for other details.

4

To show debug information for all categories, use something like

export GST_DEBUG="*:6"

before running your command.

2

The current documentation is here. Some interesting excerpts, in my opinion:

The '*' wildcard is also available. For example GST_DEBUG=2,audio*:5 will use Debug Level 5 for all categories starting with the word audio, and 2 for all the others.

Use gst-launch-1.0 --gst-debug-help to obtain the list of all registered categories.

GStreamer has the capability to output graph files. Example.

And the debug levels are:

| # | 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. |
| 8 | MEMDUMP | Logs all memory dump messages. This is the heaviest logging and|
| | | may include dumping the content of blocks of memory. |
+------------------------------------------------------------------------------+

I added debug level:

gst-debug-level=4 {0->7}

It work without build gstreamer again

Besides all these correct answers I'd like to point to this graphical tool to ease Gstreamer debug analysis:

In my case, after compiling the program, executed:

GST_DEBUG=5 ./tutorial2

Where tutorial2 is the name of executable.

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