|  |  |  | GStreamer 1.0 Core Reference Manual |  | 
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| Top | Description | ||||
#include <gst/gst.h> struct GstTypeFind; void (*GstTypeFindFunction) (GstTypeFind *find,gpointer user_data); enum GstTypeFindProbability; const guint8 * gst_type_find_peek (GstTypeFind *find,gint64 offset,guint size); void gst_type_find_suggest (GstTypeFind *find,guint probability,GstCaps *caps); void gst_type_find_suggest_simple (GstTypeFind *find,guint probability,const char *media_type,const char *fieldname,...); guint64 gst_type_find_get_length (GstTypeFind *find); gboolean gst_type_find_register (GstPlugin *plugin,const gchar *name,guint rank,GstTypeFindFunction func,const gchar *extensions,GstCaps *possible_caps,gpointer data,GDestroyNotify data_notify);
The following functions allow you to detect the media type of an unknown stream.
Last reviewed on 2005-11-09 (0.9.4)
struct GstTypeFind {
  /* private to the caller of the typefind function */
  const guint8 *  (* peek)       (gpointer         data,
                                  gint64           offset,
                                  guint            size);
  void            (* suggest)    (gpointer         data,
                                  guint            probability,
                                  GstCaps         *caps);
  gpointer         data;
  /* optional */
  guint64         (* get_length) (gpointer data);
};
Object that stores typefind callbacks. To use with GstTypeFindFactory.
void (*GstTypeFindFunction) (GstTypeFind *find,gpointer user_data);
A function that will be called by typefinding.
| 
 | A GstTypeFind structure | 
| 
 | optionnal data to pass to the function | 
typedef enum {
  GST_TYPE_FIND_NONE = 0,
  GST_TYPE_FIND_MINIMUM = 1,
  GST_TYPE_FIND_POSSIBLE = 50,
  GST_TYPE_FIND_LIKELY = 80,
  GST_TYPE_FIND_NEARLY_CERTAIN = 99,
  GST_TYPE_FIND_MAXIMUM = 100
} GstTypeFindProbability;
The probability of the typefind function. Higher values have more certainty in doing a reliable typefind.
const guint8 * gst_type_find_peek (GstTypeFind *find,gint64 offset,guint size);
Returns the size bytes of the stream to identify beginning at offset. If
offset is a positive number, the offset is relative to the beginning of the
stream, if offset is a negative number the offset is relative to the end of
the stream. The returned memory is valid until the typefinding function
returns and must not be freed.
| 
 | The GstTypeFind object the function was called with | 
| 
 | The offset | 
| 
 | The number of bytes to return | 
| Returns : | the requested data, or NULL if that data is not available. [transfer none][array length=size] | 
void gst_type_find_suggest (GstTypeFind *find,guint probability,GstCaps *caps);
If a GstTypeFindFunction calls this function it suggests the caps with the given probability. A GstTypeFindFunction may supply different suggestions in one call. It is up to the caller of the GstTypeFindFunction to interpret these values.
| 
 | The GstTypeFind object the function was called with | 
| 
 | The probability in percent that the suggestion is right | 
| 
 | The fixed GstCaps to suggest | 
void gst_type_find_suggest_simple (GstTypeFind *find,guint probability,const char *media_type,const char *fieldname,...);
If a GstTypeFindFunction calls this function it suggests the caps with the given probability. A GstTypeFindFunction may supply different suggestions in one call. It is up to the caller of the GstTypeFindFunction to interpret these values.
This function is similar to gst_type_find_suggest(), only that instead of
passing a GstCaps argument you can create the caps on the fly in the same
way as you can with gst_caps_new_simple().
Make sure you terminate the list of arguments with a NULL argument and that the values passed have the correct type (in terms of width in bytes when passed to the vararg function - this applies particularly to gdouble and guint64 arguments).
| 
 | The GstTypeFind object the function was called with | 
| 
 | The probability in percent that the suggestion is right | 
| 
 | the media type of the suggested caps | 
| 
 | first field of the suggested caps, or NULL. [allow-none] | 
| 
 | additional arguments to the suggested caps in the same format as the
arguments passed to gst_structure_new()(ie. triplets of field name,
field GType and field value) | 
guint64             gst_type_find_get_length            (GstTypeFind *find);
Get the length of the data stream.
| 
 | The GstTypeFind the function was called with | 
| Returns : | The length of the data stream, or 0 if it is not available. | 
gboolean gst_type_find_register (GstPlugin *plugin,const gchar *name,guint rank,GstTypeFindFunction func,const gchar *extensions,GstCaps *possible_caps,gpointer data,GDestroyNotify data_notify);
Registers a new typefind function to be used for typefinding. After registering this function will be available for typefinding. This function is typically called during an element's plugin initialization.
| 
 | A GstPlugin, or NULL for a static typefind function. [allow-none] | 
| 
 | The name for registering | 
| 
 | The rank (or importance) of this typefind function | 
| 
 | The GstTypeFindFunction to use | 
| 
 | Optional comma-separated list of extensions that could belong to this type. [allow-none] | 
| 
 | Optionally the caps that could be returned when typefinding succeeds | 
| 
 | Optional user data. This user data must be available until the plugin is unloaded. | 
| 
 | a GDestroyNotify that will be called on datawhen the plugin
is unloaded. | 
| Returns : | TRUE on success, FALSE otherwise |