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GStreamer 0.10 Library Reference Manual | |
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#include <gst/controller/gstcontroller.h>
GstController;
gboolean gst_controller_init (int *argc,
char ***argv);
GstController* gst_controller_new (GObject *object,
...);
GstController* gst_controller_new_list (GObject *object,
GList *list);
GstController* gst_controller_new_valist (GObject *object,
va_list var_args);
gboolean gst_controller_remove_properties (GstController *self,
...);
gboolean gst_controller_remove_properties_list
(GstController *self,
GList *list);
gboolean gst_controller_remove_properties_valist
(GstController *self,
va_list var_args);
void gst_controller_set_disabled (GstController *self,
gboolean disabled);
void gst_controller_set_property_disabled
(GstController *self,
gchar *property_name,
gboolean disabled);
GstClockTime gst_controller_suggest_next_sync (GstController *self);
gboolean gst_controller_sync_values (GstController *self,
GstClockTime timestamp);
GstControlSource* gst_controller_get_control_source (GstController *self,
gchar *property_name);
gboolean gst_controller_set_control_source (GstController *self,
gchar *property_name,
GstControlSource *csource);
GValue* gst_controller_get (GstController *self,
gchar *property_name,
GstClockTime timestamp);
gboolean gst_controller_get_value_arrays (GstController *self,
GstClockTime timestamp,
GSList *value_arrays);
gboolean gst_controller_get_value_array (GstController *self,
GstClockTime timestamp,
GstValueArray *value_array);
gboolean gst_controller_set (GstController *self,
gchar *property_name,
GstClockTime timestamp,
GValue *value);
gboolean gst_controller_set_from_list (GstController *self,
gchar *property_name,
GSList *timedvalues);
gboolean gst_controller_unset (GstController *self,
gchar *property_name,
GstClockTime timestamp);
gboolean gst_controller_unset_all (GstController *self,
gchar *property_name);
const GList* gst_controller_get_all (GstController *self,
gchar *property_name);
gboolean gst_controller_set_interpolation_mode
(GstController *self,
gchar *property_name,
GstInterpolateMode mode);
The controller subsystem offers a lightweight way to adjust gobject properties over stream-time. It works by using time-stamped value pairs that are queued for element-properties. At run-time the elements continously pull values changes for the current stream-time.
What needs to be changed in a GstElement? Very little - it is just two steps to make a plugin controllable!
mark gobject-properties paramspecs that make sense to be controlled, by GST_PARAM_CONTROLLABLE.
when processing data (get, chain, loop function) at the beginning call gst_object_sync_values(element,timestamp). This will made the controller to update all gobject properties that are under control with the current values based on timestamp.
What needs to be done in applications? Again its not a lot to change.
first put some properties under control, by calling controller = g_object_control_properties(object, "prop1", "prop2",...);
Get a GstControlSource for the property and set it up.
csource = gst_interpolation_control_source_new();
gst_interpolation_control_source_set_interpolation_mode(csource, mode);
gst_interpolation_control_source_set (csource,0 * GST_SECOND, value1);
gst_interpolation_control_source_set (csource,1 * GST_SECOND, value2);
Set the GstControlSource in the controller. gst_controller_set_control_source (controller, "prop1", csource);
start your pipeline
gboolean gst_controller_init (int *argc,
char ***argv);
Initializes the use of the controller library. Suggested to be called right
after gst_init().
argc : |
pointer to the commandline argument count |
argv : |
pointer to the commandline argument values |
| Returns : | the TRUE for success.
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GstController* gst_controller_new (GObject *object, ...);
Creates a new GstController for the given object's properties
object : |
the object of which some properties should be controlled |
... : |
NULL terminated list of property names that should be controlled
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| Returns : | the new controller. |
GstController* gst_controller_new_list (GObject *object, GList *list);
Creates a new GstController for the given object's properties
object : |
the object of which some properties should be controlled |
list : |
list of property names that should be controlled |
| Returns : | the new controller. |
GstController* gst_controller_new_valist (GObject *object, va_list var_args);
Creates a new GstController for the given object's properties
object : |
the object of which some properties should be controlled |
var_args : |
NULL terminated list of property names that should be controlled
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| Returns : | the new controller. |
gboolean gst_controller_remove_properties (GstController *self, ...);
Removes the given object properties from the controller
self : |
the controller object from which some properties should be removed |
... : |
NULL terminated list of property names that should be removed
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| Returns : | FALSE if one of the given property isn't handled by the controller, TRUE otherwise
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gboolean gst_controller_remove_properties_list
(GstController *self,
GList *list);
Removes the given object properties from the controller
self : |
the controller object from which some properties should be removed |
list : |
GList of property names that should be removed |
| Returns : | FALSE if one of the given property isn't handled by the controller, TRUE otherwise
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gboolean gst_controller_remove_properties_valist
(GstController *self,
va_list var_args);
Removes the given object properties from the controller
self : |
the controller object from which some properties should be removed |
var_args : |
NULL terminated list of property names that should be removed
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| Returns : | FALSE if one of the given property isn't handled by the controller, TRUE otherwise
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void gst_controller_set_disabled (GstController *self, gboolean disabled);
This function is used to disable all properties of the GstController
for some time, i.e. gst_controller_sync_values() will do nothing.
self : |
the GstController which should be disabled |
disabled : |
boolean that specifies whether to disable the controller or not. |
Since 0.10.14
void gst_controller_set_property_disabled
(GstController *self,
gchar *property_name,
gboolean disabled);
This function is used to disable the GstController on a property for
some time, i.e. gst_controller_sync_values() will do nothing for the
property.
self : |
the GstController which should be disabled |
property_name : |
property to disable |
disabled : |
boolean that specifies whether to disable the controller or not. |
Since 0.10.14
GstClockTime gst_controller_suggest_next_sync (GstController *self);
Returns a suggestion for timestamps where buffers should be split to get best controller results.
self : |
the controller that handles the values |
| Returns : | Returns the suggested timestamp or GST_CLOCK_TIME_NONE
if no control-rate was set.
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Since 0.10.13
gboolean gst_controller_sync_values (GstController *self, GstClockTime timestamp);
Sets the properties of the element, according to the controller that (maybe) handles them and for the given timestamp.
If this function fails, it is most likely the application developers fault. Most probably the control sources are not setup correctly.
self : |
the controller that handles the values |
timestamp : |
the time that should be processed |
| Returns : | TRUE if the controller values could be applied to the object
properties, FALSE otherwise
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GstControlSource* gst_controller_get_control_source (GstController *self, gchar *property_name);
Gets the corresponding GstControlSource for the property. This should be unreferenced again after use.
self : |
the controller object |
property_name : |
name of the property for which the GstControlSource should be get |
| Returns : | the GstControlSource for property_name or NULL if the property is not
controlled by this controller or no GstControlSource was assigned yet.
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Since 0.10.14
gboolean gst_controller_set_control_source (GstController *self, gchar *property_name, GstControlSource *csource);
Sets the GstControlSource for property_name. If there already was a GstControlSource
for this property it will be unreferenced.
self : |
the controller object |
property_name : |
name of the property for which the GstControlSource should be set |
csource : |
the GstControlSource that should be used for the property |
| Returns : | FALSE if the given property isn't handled by the controller or the new GstControlSource
couldn't be bound to the property, TRUE if everything worked as expected.
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Since 0.10.14
GValue* gst_controller_get (GstController *self, gchar *property_name, GstClockTime timestamp);
Gets the value for the given controller-handled property at the requested time.
self : |
the controller object which handles the properties |
property_name : |
the name of the property to get |
timestamp : |
the time the control-change should be read from |
| Returns : | the GValue of the property at the given time, or NULL if the
property isn't handled by the controller
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gboolean gst_controller_get_value_arrays (GstController *self, GstClockTime timestamp, GSList *value_arrays);
Function to be able to get an array of values for one or more given element properties.
All fields of the GstValueArray in the list must be filled correctly.
Especially the GstValueArray->values arrays must be big enough to keep
the requested amount of values.
The types of the values in the array are the same as the property's type.
This doesn't modify the controlled GObject properties!
self : |
the controller that handles the values |
timestamp : |
the time that should be processed |
value_arrays : |
list to return the control-values in |
| Returns : | TRUE if the given array(s) could be filled, FALSE otherwise
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gboolean gst_controller_get_value_array (GstController *self, GstClockTime timestamp, GstValueArray *value_array);
Function to be able to get an array of values for one element property.
All fields of value_array must be filled correctly. Especially the
value_array->values array must be big enough to keep the requested amount
of values.
The type of the values in the array is the same as the property's type.
This doesn't modify the controlled GObject property!
self : |
the controller that handles the values |
timestamp : |
the time that should be processed |
value_array : |
array to put control-values in |
| Returns : | TRUE if the given array could be filled, FALSE otherwise
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gboolean gst_controller_set (GstController *self, gchar *property_name, GstClockTime timestamp, GValue *value);
gst_controller_set is deprecated and should not be used in newly-written code. Use GstControlSource, for example GstInterpolationControlSource
directly.
Set the value of given controller-handled property at a certain time.
self : |
the controller object which handles the properties |
property_name : |
the name of the property to set |
timestamp : |
the time the control-change is schedules for |
value : |
the control-value |
| Returns : | FALSE if the values couldn't be set (ex : properties not handled by controller), TRUE otherwise |
gboolean gst_controller_set_from_list (GstController *self, gchar *property_name, GSList *timedvalues);
gst_controller_set_from_list is deprecated and should not be used in newly-written code. Use GstControlSource, for example GstInterpolationControlSource
directly.
Sets multiple timed values at once.
self : |
the controller object which handles the properties |
property_name : |
the name of the property to set |
timedvalues : |
a list with GstTimedValue items |
| Returns : | FALSE if the values couldn't be set (ex : properties not handled by controller), TRUE otherwise
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gboolean gst_controller_unset (GstController *self, gchar *property_name, GstClockTime timestamp);
gst_controller_unset is deprecated and should not be used in newly-written code. Use GstControlSource, for example GstInterpolationControlSource
directly.
Used to remove the value of given controller-handled property at a certain time.
self : |
the controller object which handles the properties |
property_name : |
the name of the property to unset |
timestamp : |
the time the control-change should be removed from |
| Returns : | FALSE if the values couldn't be unset (ex : properties not handled by controller), TRUE otherwise
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gboolean gst_controller_unset_all (GstController *self, gchar *property_name);
gst_controller_unset_all is deprecated and should not be used in newly-written code. Use GstControlSource, for example GstInterpolationControlSource
directly.
Used to remove all time-stamped values of given controller-handled property
self : |
the controller object which handles the properties |
property_name : |
the name of the property to unset |
| Returns : | FALSE if the values couldn't be unset (ex : properties not handled
by controller), TRUE otherwise
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Since 0.10.5
const GList* gst_controller_get_all (GstController *self, gchar *property_name);
gst_controller_get_all is deprecated and should not be used in newly-written code. Use GstControlSource, for example GstInterpolationControlSource
directly.
Returns a read-only copy of the list of GstTimedValue for the given property. Free the list after done with it.
This doesn't modify the controlled GObject property!
self : |
the controller to get the list from |
property_name : |
the name of the property to get the list for |
| Returns : | a copy of the list, or NULL if the property isn't handled by the controller
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gboolean gst_controller_set_interpolation_mode
(GstController *self,
gchar *property_name,
GstInterpolateMode mode);
gst_controller_set_interpolation_mode is deprecated and should not be used in newly-written code. Use GstControlSource, for example GstInterpolationControlSource
directly.
Sets the given interpolation mode on the given property.
User interpolation is not yet available and quadratic interpolation is deprecated and maps to cubic interpolation.
self : |
the controller object |
property_name : |
the name of the property for which to change the interpolation |
mode : |
interpolation mode |
| Returns : | TRUE if the property is handled by the controller, FALSE otherwise
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