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8 <refentry id="gst-running" revision="08 Oct 2005">
10 <refentrytitle>Running GStreamer Applications</refentrytitle>
11 <manvolnum>3</manvolnum>
12 <refmiscinfo>GStreamer Core</refmiscinfo>
16 <refname>Running GStreamer Applications</refname>
18 How to run and debug your GStreamer application
23 <title>Running and debugging GStreamer Applications</title>
26 <title>Environment variables</title>
29 GStreamer inspects a few of environment variables in addition to standard
30 variables like <envar>LANG</envar>, <envar>PATH</envar> or <envar>HOME</envar>.
33 <formalpara id="GST_PLUGIN_SYSTEM_PATH">
34 <title><envar>GST_PLUGIN_SYSTEM_PATH</envar>,
35 <envar>GST_PLUGIN_SYSTEM_PATH_1_0</envar></title>
39 This environment variable can be set to a colon-separated list of paths (or
40 semicolon-separated list on Windows).
41 If this variable is not set, GStreamer will fill in this list for you
46 plug-ins in the user's home directory, or rather the user's "data home"
47 directory according to the xdg base dir specification. Usually this will be
49 <filename>plugins</filename> inside the
50 <filename>.local/share/gstreamer-&GST_API_VERSION;</filename> directory in
51 the user's home directory by default, though this search path may change if
52 the XDG_DATA_HOME environment variable is set.
57 plug-ins installed system-wide. On this system, they are stored in
58 <filename>&GST_PLUGINS_DIR;</filename>.
66 GStreamer will scan these paths for GStreamer plug-ins. These plug-ins will
67 be loaded after the plug-ins in the GST_PLUGIN_PATH variable below.
69 The paths are scanned in the given order. This allows a user to override
70 system-installed plug-ins with his own versions.
73 The GST_PLUGIN_SYSTEM_PATH_1_0 variant is useful if both the old GStreamer 0.10
74 version and the new GStreamer 1.0 version need to be pointed to new plugin
75 paths. The latter will use the _1_0 variant over the non-versioned one if
80 Setting this variable to an empty string will cause GStreamer not to scan any
81 system paths at all for plug-ins. This can be useful if you're running
82 uninstalled (for development purposes) or while running testsuites.
87 <formalpara id="GST_PLUGIN_PATH">
88 <title><envar>GST_PLUGIN_PATH</envar>, <envar>GST_PLUGIN_PATH_1_0</envar></title>
91 This environment variable can be set to a colon-separated list of paths (or a
92 semicolon-separated list on Windows).
93 GStreamer will scan these paths for GStreamer plug-ins. These plug-ins will
94 be loaded in addition to, and before, the plug-ins in the system paths.
97 The GST_PLUGIN_PATH_1_0 variant is useful if both the old GStreamer 0.10
98 version and the new GStreamer 1.0 version need to be pointed to new plugin
99 paths. The latter will use the _1_0 variant over the non-versioned one if
104 <formalpara id="GST_DEBUG">
105 <title><envar>GST_DEBUG</envar></title>
108 If GStreamer has been configured with <option>--enable-gst-debug=yes</option>,
109 this variable can be set to a list of debug options, which cause GStreamer
110 to print out different types of debugging information to stderr.
113 The variable takes a comma-separated list of "category_name:level" pairs
114 to set specific levels for the individual categories.
115 The level value ranges from 0 (nothing) to 9 (MEMDUMP).
119 <term>1 - <option>ERROR</option></term>
122 Logs all fatal errors. These are errors that do not allow the core or elements
123 to perform the requested action. The application can still recover if
124 programmed to handle the conditions that triggered the error.
130 <term>2 - <option>WARNING</option></term>
133 Logs all warnings. Typically these are non-fatal, but user-visible problems
134 are expected to happen.
140 <term>3 - <option>FIXME</option></term>
143 Logs all fixme messages. Fixme messages are messages that indicate that something
144 in the executed code path is not fully implemented or handled yet. The purpose
145 of this message is to make it easier to spot incomplete/unfinished pieces of
146 code when reading the debug log.
152 <term>4 - <option>INFO</option></term>
155 Logs all informational messages. These are typically used for events in
156 the system that only happen once, or are important and rare enough to be
157 logged at this level.
163 <term>5 - <option>DEBUG</option></term>
166 Logs all debug messages. These are general debug messages for events
167 that happen only a limited number of times during an object's lifetime;
168 these include setup, teardown, change of parameters, ...
174 <term>6 - <option>LOG</option></term>
177 Logs all log messages. These are messages for events
178 that happen repeatedly during an object's lifetime;
179 these include streaming and steady-state conditions.
185 <term>7 - <option>TRACE</option></term>
188 Logs all trace messages. These messages for events
189 that happen repeatedly during an object's lifetime such as the
196 <term>9 - <option>MEMDUMP</option></term>
199 Log all memory dump messages. Memory dump messages are used to log
200 (small) chunks of data as memory dumps in the log. They will be displayed
201 as hexdump with ASCII characters.
207 The category_name can contain "<option>*"</option> as a wildcard.
211 For example, setting <envar>GST_DEBUG</envar> to
212 <option>GST_AUTOPLUG:6,GST_ELEMENT_*:4</option>, will cause the
213 <option>GST_AUTOPLUG</option> category to be logged at full
214 <option>LOG</option> level, while all categories starting with
215 <option>GST_ELEMENT_</option> will be logged at <option>INFO</option> level.
219 To get all possible debug output, set
220 <envar>GST_DEBUG</envar>
221 to <option>*:9</option>. For debugging purposes a <option>*:6</option> debug
222 log is usually the most useful, as it contains all important information, but
223 hides a lot of noise such as refs/unrefs. For bug reporting purposes, a
224 <option>*:6</option> log is also what will be requested usually. It's often
225 also worth running with <option>*:3</option> to see if there are any
226 non-fatal errors or warnings that might be related to the problem at hand.
230 Since GStreamer 1.2 it is also possible to specify debug levels by name,
231 e.g. GST_DEBUG=*:WARNING,*audio*:LOG
236 <formalpara id="GST_DEBUG_NO_COLOR">
237 <title><envar>GST_DEBUG_NO_COLOR</envar></title>
240 Set this environment variable to any value ("1" typically) to switch off
241 colouring in GST_DEBUG output. This has the same effect as specifying the
242 <option>--gst-debug-no-color</option> or
243 <option>--gst-debug-color-mode</option>=off command line option to
244 well-behaved GStreamer applications (ie. those that pass command-line
245 options correctly to GStreamer).
246 This is particularly useful to reduce the size of debug output and also allows
247 for the output to be compressed much better than with colours turned on.
250 Has the same effect as setting GST_DEBUG_COLOR_MODE environment variable to
256 <formalpara id="GST_DEBUG_COLOR_MODE">
257 <title><envar>GST_DEBUG_COLOR_MODE</envar></title>
260 Set this environment variable to change log colouring in GST_DEBUG output.
265 <term><option>on</option></term>
268 Enables debug log output coloring. Uses default coloring method for current
269 platform. This is the default.
275 <term><option>off</option></term>
278 Disables debug log output coloring. This has the same effect as specifying the
279 <option>--gst-debug-color-mode</option>=off command line option to
280 well-behaved GStreamer applications (ie. those that pass command-line
281 options correctly to GStreamer).
282 This is particularly useful to reduce the size of debug output and also allows
283 for the output to be compressed much better than with colours turned on.
286 Has the same effect as setting GST_DEBUG_NO_COLOR environment variable to
293 <term><option>auto</option></term>
296 Same as <option>on</option>.
302 <term><option>disable</option></term>
305 Same as <option>off</option>.
311 <term><option>unix</option></term>
314 Enables debug log output coloring and forces the use of UNIX termial codes
315 for coloring, even if this method is not normally used on current platform.
316 This has the same effect as specifying the
317 <option>--gst-debug-color-mode</option>=unix command line option to
318 well-behaved GStreamer applications (ie. those that pass command-line options
319 correctly to GStreamer).
320 This is particularly useful to dump debug output into a file on non-UNIX
321 platforms to be sent to developers who have viewers that support UNIX terminal
332 <formalpara id="GST_DEBUG_OPTIONS">
333 <title><envar>GST_DEBUG_OPTIONS</envar></title>
336 This environment variable can be used to tweak the behaviour of the debugging
337 system. Currently the only options supported are "pretty-tags" and "full-tags".
338 In "pretty-tags" mode (the default), taglists in the debug log will be
339 serialized so that only the first few and last few bytes of a buffer-type tag
340 will be serialized into the log, to avoid dumping hundreds of lines of useless
341 output into the log in case of large image tags and the like.
346 <formalpara id="GST_DEBUG_DUMP_DOT_DIR">
347 <title><envar>GST_DEBUG_DUMP_DOT_DIR</envar></title>
350 Set this environment variable to a path to turn on all
351 #GST_DEBUG_BIN_TO_DOT_FILE or #GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS calls
352 and have the dot files in that location.
355 This will only work if the application in question makes these calls in
356 strategic places (like when the pipeline state changes or an error occurs).
357 gst-launch-&GST_API_VERSION; is one such application.
360 When gst-launch-&GST_API_VERSION; changes state through NULL to PLAYING
361 and back to NULL, a dot file is generated on each state change. To have
362 gst-launch-&GST_API_VERSION; write a snapshot of the pipeline state, send
363 a SIGHUP to the gst-launch-&GST_API_VERSION; process.
366 These .dot files can then be turned into images using the 'dot' utility
367 from the graphviz set of tools, like this:
368 <command>dot foo.dot -Tsvg -o foo.svg</command> or
369 <command>dot foo.dot -Tpng -o foo.png</command> or
370 <command>dot foo.dot -Tjpg -o foo.jpg</command>.
373 There is also a utility called <command>xdot</command> which allows you to
374 view the dot file directly without converting it first.
380 <formalpara id="GST_REGISTRY">
381 <title><envar>GST_REGISTRY</envar>, <envar>GST_REGISTRY_1_0</envar></title>
384 Set this environment variable to make GStreamer use a different file for the
385 plugin cache / registry than the default one. This is useful when operating
386 in a separate environment which should not affect the default cache in the
387 user's home directory.
392 <formalpara id="GST_REGISTRY_FORK">
393 <title><envar>GST_REGISTRY_FORK</envar></title>
396 Set this environment variable to "no" to prevent GStreamer from forking on
397 startup in order to update the plugin registry. This is useful for debugging
398 purposes, but should not be used under normal circumstances, since it means
399 that plugins may be loaded into memory even if they are not needed by the
405 <formalpara id="GST_REGISTRY_UPDATE">
406 <title><envar>GST_REGISTRY_UPDATE</envar></title>
409 Set this environment variable to "no" to prevent GStreamer from updating the
410 plugin registry. This is useful for embedded device which is not updating the
411 plugins frequently, it will save time when doing gst_init().
416 <formalpara id="GST_TRACE">
417 <title><envar>GST_TRACE</envar></title>
420 Enable memory allocation tracing. Most GStreamer objects have support for
421 tracing the number of unfreed objects and their memory pointers.
424 The variable takes a comma-separated list of tracing options to enable.
431 Counts all live objects and dumps an overview of the number of unfreed
432 objects at program exit.
438 <term>mem-live</term>
441 Keep track of the unfreed memory pointers and dump an overview of all unfreed
442 memory at program exit. Together with a level 9 debug log this can be used to
443 follow the lifecycle of leaked objects in order to track down where they are
444 leaked. This can be useful for debugging memory leaks in situations where
445 tools such as valgrind are not available, or not an option.
451 Use <option>all</option> to enable all tracing flags.
455 <formalpara id="GST_DEBUG_FILE">
456 <title><envar>GST_DEBUG_FILE</envar></title>
459 Set this variable to a file path to redirect all GStreamer debug
460 messages to this file. If left unset, debug messages with be output
461 unto the standard error.
466 <formalpara id="ORC_CODE">
467 <title><envar>ORC_CODE</envar></title>
470 Useful Orc environment variable. Set ORC_CODE=debug to enable debuggers
471 such as gdb to create useful backtraces from Orc-generated code. Set
472 ORC_CODE=backup or ORC_CODE=emulate if you suspect Orc's SIMD code
473 generator is producing incorrect code (Quite a few important
474 GStreamer plugins like videotestsrc, audioconvert or audioresample use Orc).
475 One can also combine flags like ORC_CODE=backup,debug.
480 <formalpara id="G_DEBUG">
481 <title><envar>G_DEBUG</envar></title>
484 Useful GLib environment variable. Set G_DEBUG=fatal_warnings to make
485 GStreamer programs abort when a critical warning such as an assertion failure
486 occurs. This is useful if you want to find out which part of the code caused
487 that warning to be triggered and under what circumstances. Simply set G_DEBUG
488 as mentioned above and run the program in gdb (or let it core dump). Then get
489 a stack trace in the usual way.
494 <formalpara id="G_SLICE">
495 <title><envar>G_SLICE</envar></title>
498 Useful GLib environment variable. Set G_SLICE=always-malloc when running
499 GStreamer programs in valgrind, or debugging memory leaks with other tools.
500 See the GLib API reference for more details.
505 <formalpara id="GST_TAG_ENCODING">
506 <title><envar>GST_TAG_ENCODING</envar></title>
508 Try this character encoding first for tag-related strings where the encoding
509 is not defined and which are not UTF-8 already. By default the current locale
510 will be tried (if not UTF-8).
514 <formalpara id="GST_TAG_ID3_ENCODING">
515 <title><envar>GST_TAG_ID3_ENCODING</envar></title>
517 Try this character encoding first for ID3 tag-related strings where the
518 encoding is not defined and which are not UTF-8 already. By default the current
519 locale will be tried (if not UTF-8).
523 <formalpara id="GST_TAG_ID3V1_ENCODING">
524 <title><envar>GST_TAG_ID3V1_ENCODING</envar></title>
526 Try this character encoding first for ID3v1 tag-related strings where the
527 encoding does not look like UTF-8.
531 <formalpara id="GST_GL_WINDOW">
532 <title><envar>GST_GL_WINDOW</envar></title>
534 Influences the window system to use by the GStreamer OpenGL library.
535 Common values are 'x11', 'wayland', 'win32' or 'cocoa'.
539 <formalpara id="GST_GL_PLATFORM">
540 <title><envar>GST_GL_PLATFORM</envar></title>
542 Influences the OpenGL platform to use by the GStreamer OpenGL library.
543 Common values are 'egl', 'glx', 'wgl' or 'cgl'.
547 <formalpara id="GST_GL_API">
548 <title><envar>GST_GL_API</envar></title>
550 Influences the OpenGL API requested by the OpenGL platform.
551 Common values are 'opengl' or 'gles2'.