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GStreamer 0.10 Library Reference Manual | |
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#include <libs/controller/gstcontrolsource.h>
GstControlSource;
GstControlSourceClass;
gboolean (*GstControlSourceBind) (GstControlSource *self,
GParamSpec *pspec);
gboolean (*GstControlSourceGetValue) (GstControlSource *self,
GstClockTime timestamp,
GValue *value);
gboolean (*GstControlSourceGetValueArray) (GstControlSource *self,
GstClockTime timestamp,
GstValueArray *value_array);
GstTimedValue;
GstValueArray;
gboolean gst_control_source_bind (GstControlSource *self,
GParamSpec *pspec);
gboolean gst_control_source_get_value (GstControlSource *self,
GstClockTime timestamp,
GValue *value);
gboolean gst_control_source_get_value_array (GstControlSource *self,
GstClockTime timestamp,
GstValueArray *value_array);
GObject
+----GstControlSource
+----GstInterpolationControlSource
+----GstLFOControlSource
The GstControlSource is a base class for control value sources that could be used by GstController to get timestamp-value pairs.
A GstControlSource is used by first getting an instance, binding it to a
GParamSpec (for example by using gst_controller_set_control_source()) and
then by having it used by the GstController or calling
gst_control_source_get_value() or gst_control_source_get_value_array().
For implementing a new GstControlSource one has to implement a
GstControlSourceBind method, which will depending on the GParamSpec set up
the control source for use and sets the GstControlSourceGetValue and
GstControlSourceGetValueArray functions. These are then used by
gst_control_source_get_value() or gst_control_source_get_value_array()
to get values for specific timestamps.
typedef struct {
GstControlSourceGetValue get_value; /* Returns the value for a property at a given timestamp */
GstControlSourceGetValueArray get_value_array; /* Returns values for a property in a given timespan */
} GstControlSource;
The instance structure of GstControlSource.
GstControlSourceGetValue get_value; |
Function for returning a value for a given timestamp |
GstControlSourceGetValueArray get_value_array; |
Function for returning a GstValueArray for a given timestamp |
typedef struct {
GObjectClass parent_class;
GstControlSourceBind bind; /* Binds the GstControlSource to a specific GParamSpec */
} GstControlSourceClass;
The class structure of GstControlSource.
GObjectClass parent_class; |
Parent class |
GstControlSourceBind bind; |
Class method for binding the GstControlSource to a specific GParamSpec |
gboolean (*GstControlSourceBind) (GstControlSource *self, GParamSpec *pspec);
Function for binding a GstControlSource to a GParamSpec.
self : |
the GstControlSource instance |
pspec : |
GParamSpec that should be bound to |
| Returns : | TRUE if the property could be bound to the GstControlSource, FALSE otherwise.
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gboolean (*GstControlSourceGetValue) (GstControlSource *self, GstClockTime timestamp, GValue *value);
Function for returning a value for a given timestamp.
self : |
the GstControlSource instance |
timestamp : |
timestamp for which a value should be calculated |
value : |
a GValue which will be set to the result. It must be initialized to the correct type. |
| Returns : | TRUE if the value was successfully calculated.
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gboolean (*GstControlSourceGetValueArray) (GstControlSource *self, GstClockTime timestamp, GstValueArray *value_array);
Function for returning a GstValueArray for a given timestamp.
self : |
the GstControlSource instance |
timestamp : |
timestamp for which a value should be calculated |
value_array : |
array to put control-values in |
| Returns : | TRUE if the values were successfully calculated.
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typedef struct {
GstClockTime timestamp;
GValue value;
} GstTimedValue;
Structure for saving a timestamp and a value.
GstClockTime timestamp; |
timestamp of the value change |
GValue value; |
the corresponding value |
typedef struct {
gchar *property_name;
gint nbsamples;
GstClockTime sample_interval;
gpointer *values;
} GstValueArray;
Structure to receive multiple values at once.
gchar *property_name; |
the name of the property this array belongs to |
gint nbsamples; |
number of samples requested |
GstClockTime sample_interval; |
interval between each sample |
gpointer *values; |
pointer to the array |
gboolean gst_control_source_bind (GstControlSource *self, GParamSpec *pspec);
Binds a GstControlSource to a specific property. This must be called only once for a GstControlSource.
self : |
the GstControlSource object |
pspec : |
GParamSpec for the property for which this GstControlSource should generate values. |
| Returns : | TRUE if the GstControlSource was bound correctly, FALSE otherwise.
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gboolean gst_control_source_get_value (GstControlSource *self, GstClockTime timestamp, GValue *value);
Gets the value for this GstControlSource at a given timestamp.
self : |
the GstControlSource object |
timestamp : |
the time for which the value should be returned |
value : |
the value |
| Returns : | FALSE if the value couldn't be returned, TRUE otherwise. |
gboolean gst_control_source_get_value_array (GstControlSource *self, GstClockTime timestamp, GstValueArray *value_array);
Gets 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.
self : |
the GstControlSource object |
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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