GStreamer Base Plugins 1.0 Library Reference Manual: gstdiscoverer

## gstdiscoverer gstdiscoverer — Utility for discovering information on URIs. |

## Functions

GstDiscoverer * | gst_discoverer_new ()
void | gst_discoverer_start ()
void | gst_discoverer_stop ()
GstDiscovererInfo * | gst_discoverer_discover_uri ()
gboolean | gst_discoverer_discover_uri_async ()
GstClockTime | gst_discoverer_info_get_duration ()
const GstStructure * | gst_discoverer_info_get_misc ()
GstDiscovererResult | gst_discoverer_info_get_result ()
GstDiscovererStreamInfo * | gst_discoverer_info_get_stream_info ()
GList * | gst_discoverer_info_get_stream_list ()
const GstTagList * | gst_discoverer_info_get_tags ()
const GstToc * | gst_discoverer_info_get_toc ()
const gchar * | gst_discoverer_info_get_uri ()
gboolean | gst_discoverer_info_get_seekable ()
#define | gst_discoverer_info_ref()
#define | gst_discoverer_info_unref()
GstCaps * | gst_discoverer_stream_info_get_caps ()
const GstStructure * | gst_discoverer_stream_info_get_misc ()
GstDiscovererStreamInfo * | gst_discoverer_stream_info_get_next ()
GstDiscovererStreamInfo * | gst_discoverer_stream_info_get_previous ()
const GstTagList * | gst_discoverer_stream_info_get_tags ()
const GstToc * | gst_discoverer_stream_info_get_toc ()
const gchar * | gst_discoverer_stream_info_get_stream_id ()
#define | gst_discoverer_stream_info_ref()
#define | gst_discoverer_stream_info_unref()
void | gst_discoverer_stream_info_list_free ()
const gchar * | gst_discoverer_stream_info_get_stream_type_nick ()
GList * | gst_discoverer_info_get_audio_streams ()
GList * | gst_discoverer_info_get_container_streams ()
GList * | gst_discoverer_info_get_streams ()
GList * | gst_discoverer_info_get_subtitle_streams ()
GList * | gst_discoverer_info_get_video_streams ()
guint | gst_discoverer_audio_info_get_bitrate ()
guint | gst_discoverer_audio_info_get_channels ()
guint | gst_discoverer_audio_info_get_depth ()
const gchar * | gst_discoverer_audio_info_get_language ()
guint | gst_discoverer_audio_info_get_max_bitrate ()
guint | gst_discoverer_audio_info_get_sample_rate ()
GList * | gst_discoverer_container_info_get_streams ()
const gchar * | gst_discoverer_subtitle_info_get_language ()
guint | gst_discoverer_video_info_get_bitrate ()
guint | gst_discoverer_video_info_get_depth ()
guint | gst_discoverer_video_info_get_framerate_denom ()
guint | gst_discoverer_video_info_get_framerate_num ()
guint | gst_discoverer_video_info_get_height ()
gboolean | gst_discoverer_video_info_is_interlaced ()
gboolean | gst_discoverer_video_info_is_image ()
guint | gst_discoverer_video_info_get_max_bitrate ()
guint | gst_discoverer_video_info_get_par_denom ()
guint | gst_discoverer_video_info_get_par_num ()
guint | gst_discoverer_video_info_get_width ()

## Properties

guint64 | timeout | Read / Write / Construct

## Signals

void | discovered | Run Last
void | finished | Run Last
void | source-setup | Run Last
void | starting | Run Last

## Types and Values

struct | GstDiscoverer
| GstDiscovererInfo
enum | GstDiscovererResult
| GstDiscovererStreamInfo
| GstDiscovererContainerInfo
| GstDiscovererAudioInfo
| GstDiscovererVideoInfo
| GstDiscovererSubtitleInfo

## Object Hierarchy

        GObject
        ├── GstDiscoverer
        ╰── GstDiscovererInfo

## Includes

    #include <gst/pbutils/pbutils.h>

## Description

The GstDiscoverer is a utility object which allows to get as much information as possible from one or many URIs.

It provides two APIs, allowing usage in blocking or non-blocking mode.

The blocking mode just requires calling `gst_discoverer_discover_uri()` with the URI one wishes to discover.

The non-blocking mode requires a running GMainLoop in the default GMainContext, where one connects to the various signals, appends the URIs to be processed (through `gst_discoverer_discover_uri_async()`) and then asks for the discovery to begin (through `gst_discoverer_start()`).

All the information is returned in a GstDiscovererInfo structure.

## Functions

### gst_discoverer_new ()

    GstDiscoverer *
    gst_discoverer_new (GstClockTime timeout,
                        GError **err);

Creates a new GstDiscoverer with the provided timeout.

#### Parameters

timeout | timeout per file, in nanoseconds. Allowed are values between one second (GST_SECOND) and one hour (3600 * GST_SECOND) |
err | a pointer to a GError. can be `NULL` |

#### Returns

The new GstDiscoverer. If an error occurred when creating the discoverer, `err` will be set accordingly and `NULL` will be returned. If `err` is set, the caller must free it when no longer needed using `g_error_free()`.

[transfer full]

### gst_discoverer_start ()

    void
    gst_discoverer_start (GstDiscoverer *discoverer);

Allow asynchronous discovering of URIs to take place. A GMainLoop must be available for GstDiscoverer to properly work in asynchronous mode.

#### Parameters

discoverer | A GstDiscoverer |

### gst_discoverer_stop ()

    void
    gst_discoverer_stop (GstDiscoverer *discoverer);

Stop the discovery of any pending URIs and clears the list of pending URIS (if any).

#### Parameters

discoverer | A GstDiscoverer |

### gst_discoverer_discover_uri ()

    GstDiscovererInfo *
    gst_discoverer_discover_uri (GstDiscoverer *discoverer,
                                 const gchar *uri,
                                 GError **err);

Synchronously discovers the given `uri` .

A copy of `uri` will be made internally, so the caller can safely `g_free()` afterwards.

#### Parameters

discoverer | A GstDiscoverer |
uri | The URI to run on. |
err | If an error occurred, this field will be filled in. | [out][allow-none]

#### Returns

the result of the scanning. Can be `NULL` if an error occurred.

[transfer full]

### gst_discoverer_discover_uri_async ()

    gboolean
    gst_discoverer_discover_uri_async (GstDiscoverer *discoverer,
                                       const gchar *uri);

Appends the given `uri` to the list of URIs to discoverer. The actual discovery of the `uri` will only take place if `gst_discoverer_start()` has been called.

A copy of `uri` will be made internally, so the caller can safely `g_free()` afterwards.

#### Parameters

discoverer | A GstDiscoverer |
uri | the URI to add. |

#### Returns

`TRUE` if the `uri` was successfully appended to the list of pending uris, else `FALSE`

### gst_discoverer_info_get_duration ()

    GstClockTime
    gst_discoverer_info_get_duration (const GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

the duration of the URI in GstClockTime (nanoseconds).

### gst_discoverer_info_get_misc ()

    const GstStructure *
    gst_discoverer_info_get_misc (const GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

Miscellaneous information stored as a GstStructure (for example: information about missing plugins). If you wish to use the GstStructure after the life-time of `info` , you will need to copy it.

[transfer none]

### gst_discoverer_info_get_result ()

    GstDiscovererResult
    gst_discoverer_info_get_result (const GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

the result of the discovery as a GstDiscovererResult.

### gst_discoverer_info_get_stream_info ()

    GstDiscovererStreamInfo *
    gst_discoverer_info_get_stream_info (GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

the structure (or topology) of the URI as a GstDiscovererStreamInfo. This structure can be traversed to see the original hierarchy. Unref with `gst_discoverer_stream_info_unref()` after usage.

[transfer full]

### gst_discoverer_info_get_stream_list ()

    GList *
    gst_discoverer_info_get_stream_list (GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

the list of all streams contained in the info. Free after usage with `gst_discoverer_stream_info_list_free()`.

[transfer full][element-type GstPbutils.DiscovererStreamInfo]

### gst_discoverer_info_get_tags ()

    const GstTagList *
    gst_discoverer_info_get_tags (const GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

all tags contained in the URI. If you wish to use the tags after the life-time of `info` , you will need to copy them.

[transfer none]

### gst_discoverer_info_get_toc ()

    const GstToc *
    gst_discoverer_info_get_toc (const GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

TOC contained in the URI. If you wish to use the TOC after the life-time of `info` , you will need to copy it.

[transfer none]

### gst_discoverer_info_get_uri ()

    const gchar *
    gst_discoverer_info_get_uri (const GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

the URI to which this information corresponds to. Copy it if you wish to use it after the life-time of `info` .

[transfer none]

### gst_discoverer_info_get_seekable ()

    gboolean
    gst_discoverer_info_get_seekable (const GstDiscovererInfo *info);

#### Parameters

info | a GstDiscovererInfo |

#### Returns

the whether the URI is seekable.

### gst_discoverer_info_ref()

    #define gst_discoverer_info_ref(info) (g_object_ref((Gbject*)info))

Increments the reference count of `info` .

#### Parameters

info | a GstDiscovererInfo |

#### Returns

the same GstDiscovererInfo object

### gst_discoverer_info_unref()

    #define gst_discoverer_info_unref(info) (g_object_unref((GObject*)info))

Decrements the reference count of `info` .

#### Parameters

info | a GstDiscovererInfo |

### gst_discoverer_stream_info_get_caps ()

    GstCaps *
    gst_discoverer_stream_info_get_caps (GstDiscovererStreamInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

the GstCaps of the stream. Unref with gst_caps_unref after usage.

[transfer full]

### gst_discoverer_stream_info_get_misc ()

    const GstStructure *
    gst_discoverer_stream_info_get_misc (GstDiscovererStreamInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

additional information regarding the stream (for example codec version, profile, etc..). If you wish to use the GstStructure after the life-time of `info` you will need to copy it.

[transfer none]

### gst_discoverer_stream_info_get_next ()

    GstDiscovererStreamInfo *
    gst_discoverer_stream_info_get_next (GstDiscovererStreamInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

the next GstDiscovererStreamInfo in a chain. `NULL` for final streams. Unref with gst_discoverer_stream_info_unref after usage.

[transfer full]

### gst_discoverer_stream_info_get_previous ()

    GstDiscovererStreamInfo *
    gst_discoverer_stream_info_get_previous
                                   (GstDiscovererStreamInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

the previous GstDiscovererStreamInfo in a chain. `NULL` for starting points. Unref with gst_discoverer_stream_info_unref after usage.

[transfer full]

### gst_discoverer_stream_info_get_tags ()

    const GstTagList *
    gst_discoverer_stream_info_get_tags (GstDiscovererStreamInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

the tags contained in this stream. If you wish to use the tags after the life-time of `info` you will need to copy them.

[transfer none]

### gst_discoverer_stream_info_get_toc ()

    const GstToc *
    gst_discoverer_stream_info_get_toc (GstDiscovererStreamInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

the TOC contained in this stream. If you wish to use the TOC after the life-time of `info` you will need to copy it.

[transfer none]

### gst_discoverer_stream_info_get_stream_id ()

    const gchar *
    gst_discoverer_stream_info_get_stream_id
                                   (GstDiscovererStreamInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

the stream ID of this stream. If you wish to use the stream ID after the life-time of `info` you will need to copy it.

[transfer none]

### gst_discoverer_stream_info_ref()

    #define gst_discoverer_stream_info_ref(info) ((GstDiscovererStreamInfo*) g_object_ref((GObject*) info))

Increments the reference count of `info` .

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

the same GstDiscovererStreamInfo object

### gst_discoverer_stream_info_unref()

    #define gst_discoverer_stream_info_unref(info) (g_object_unref((GObject*) info))

Decrements the reference count of `info` .

#### Parameters

info | a GstDiscovererStreamInfo |

### gst_discoverer_stream_info_list_free ()

    void
    gst_discoverer_stream_info_list_free (GList *infos);

Decrements the reference count of all contained GstDiscovererStreamInfo and fress the GList.

#### Parameters

infos | a GList of GstDiscovererStreamInfo. | [element-type GstPbutils.DiscovererStreamInfo]

### gst_discoverer_stream_info_get_stream_type_nick ()

    const gchar *
    gst_discoverer_stream_info_get_stream_type_nick
                                   (GstDiscovererStreamInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

a human readable name for the stream type of the given `info` (ex : "audio", "container",...).

### gst_discoverer_info_get_audio_streams ()

    GList *
    gst_discoverer_info_get_audio_streams (GstDiscovererInfo *info);

Finds all the GstDiscovererAudioInfo contained in `info`

#### Parameters

info | a GstDiscovererInfo |

#### Returns

A GList of matching GstDiscovererStreamInfo. The caller should free it with `gst_discoverer_stream_info_list_free()`.

[transfer full][element-type GstPbutils.DiscovererStreamInfo]

### gst_discoverer_info_get_container_streams ()

    GList *
    gst_discoverer_info_get_container_streams
                                   (GstDiscovererInfo *info);

Finds all the GstDiscovererContainerInfo contained in `info`

#### Parameters

info | a GstDiscovererInfo |

#### Returns

A GList of matching GstDiscovererStreamInfo. The caller should free it with `gst_discoverer_stream_info_list_free()`.

[transfer full][element-type GstPbutils.DiscovererStreamInfo]

### gst_discoverer_info_get_streams ()

    GList *
    gst_discoverer_info_get_streams (GstDiscovererInfo *info,
                                     GType streamtype);

Finds the GstDiscovererStreamInfo contained in `info` that match the given `streamtype` .

#### Parameters

info | a GstDiscovererInfo |
streamtype | a GType derived from GstDiscovererStreamInfo |

#### Returns

A GList of matching GstDiscovererStreamInfo. The caller should free it with `gst_discoverer_stream_info_list_free()`.

[transfer full][element-type GstPbutils.DiscovererStreamInfo]

### gst_discoverer_info_get_subtitle_streams ()

    GList *
    gst_discoverer_info_get_subtitle_streams
                                   (GstDiscovererInfo *info);

Finds all the GstDiscovererSubtitleInfo contained in `info`

#### Parameters

info | a GstDiscovererInfo |

#### Returns

A GList of matching GstDiscovererStreamInfo. The caller should free it with `gst_discoverer_stream_info_list_free()`.

[transfer full][element-type GstPbutils.DiscovererStreamInfo]

### gst_discoverer_info_get_video_streams ()

    GList *
    gst_discoverer_info_get_video_streams (GstDiscovererInfo *info);

Finds all the GstDiscovererVideoInfo contained in `info`

#### Parameters

info | a GstDiscovererInfo |

#### Returns

A GList of matching GstDiscovererStreamInfo. The caller should free it with `gst_discoverer_stream_info_list_free()`.

[transfer full][element-type GstPbutils.DiscovererStreamInfo]

### gst_discoverer_audio_info_get_bitrate ()

    guint
    gst_discoverer_audio_info_get_bitrate (const GstDiscovererAudioInfo *info);

#### Parameters

info | a GstDiscovererAudioInfo |

#### Returns

the average or nominal bitrate of the stream in bits/second.

### gst_discoverer_audio_info_get_channels ()

    guint
    gst_discoverer_audio_info_get_channels
                                   (const GstDiscovererAudioInfo *info);

#### Parameters

info | a GstDiscovererAudioInfo |

#### Returns

the number of channels in the stream.

### gst_discoverer_audio_info_get_depth ()

    guint
    gst_discoverer_audio_info_get_depth (const GstDiscovererAudioInfo *info);

#### Parameters

info | a GstDiscovererAudioInfo |

#### Returns

the number of bits used per sample in each channel.

### gst_discoverer_audio_info_get_language ()

    const gchar *
    gst_discoverer_audio_info_get_language
                                   (const GstDiscovererAudioInfo *info);

#### Parameters

info | a GstDiscovererAudioInfo |

#### Returns

the language of the stream, or NULL if unknown.

### gst_discoverer_audio_info_get_max_bitrate ()

    guint
    gst_discoverer_audio_info_get_max_bitrate
                                   (const GstDiscovererAudioInfo *info);

#### Parameters

info | a GstDiscovererAudioInfo |

#### Returns

the maximum bitrate of the stream in bits/second.

### gst_discoverer_audio_info_get_sample_rate ()

    guint
    gst_discoverer_audio_info_get_sample_rate
                                   (const GstDiscovererAudioInfo *info);

#### Parameters

info | a GstDiscovererAudioInfo |

#### Returns

the sample rate of the stream in Hertz.

### gst_discoverer_container_info_get_streams ()

    GList *
    gst_discoverer_container_info_get_streams
                                   (GstDiscovererContainerInfo *info);

#### Parameters

info | a GstDiscovererStreamInfo |

#### Returns

the list of GstDiscovererStreamInfo this container stream offers. Free with `gst_discoverer_stream_info_list_free()` after usage.

[transfer full][element-type GstPbutils.DiscovererStreamInfo]

### gst_discoverer_subtitle_info_get_language ()

    const gchar *
    gst_discoverer_subtitle_info_get_language
                                   (const GstDiscovererSubtitleInfo *info);

#### Parameters

info | a GstDiscovererSubtitleInfo |

#### Returns

the language of the stream, or NULL if unknown.

### gst_discoverer_video_info_get_bitrate ()

    guint
    gst_discoverer_video_info_get_bitrate (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the average or nominal bitrate of the video stream in bits/second.

### gst_discoverer_video_info_get_depth ()

    guint
    gst_discoverer_video_info_get_depth (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the depth in bits of the video stream.

### gst_discoverer_video_info_get_framerate_denom ()

    guint
    gst_discoverer_video_info_get_framerate_denom
                                   (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the framerate of the video stream (denominator).

### gst_discoverer_video_info_get_framerate_num ()

    guint
    gst_discoverer_video_info_get_framerate_num
                                   (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the framerate of the video stream (numerator).

### gst_discoverer_video_info_get_height ()

    guint
    gst_discoverer_video_info_get_height (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the height of the video stream in pixels.

### gst_discoverer_video_info_is_interlaced ()

    gboolean
    gst_discoverer_video_info_is_interlaced
                                   (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

`TRUE` if the stream is interlaced, else `FALSE`.

### gst_discoverer_video_info_is_image ()

    gboolean
    gst_discoverer_video_info_is_image (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

TRUE if the video stream corresponds to an image (i.e. only contains one frame).

### gst_discoverer_video_info_get_max_bitrate ()

    guint
    gst_discoverer_video_info_get_max_bitrate
                                   (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the maximum bitrate of the video stream in bits/second.

### gst_discoverer_video_info_get_par_denom ()

    guint
    gst_discoverer_video_info_get_par_denom
                                   (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the Pixel Aspect Ratio (PAR) of the video stream (denominator).

### gst_discoverer_video_info_get_par_num ()

    guint
    gst_discoverer_video_info_get_par_num (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the Pixel Aspect Ratio (PAR) of the video stream (numerator).

### gst_discoverer_video_info_get_width ()

    guint
    gst_discoverer_video_info_get_width (const GstDiscovererVideoInfo *info);

#### Parameters

info | a GstDiscovererVideoInfo |

#### Returns

the width of the video stream in pixels.

## Types and Values

### struct GstDiscoverer

    struct GstDiscoverer;

The GstDiscoverer structure.

### GstDiscovererInfo

    typedef struct _GstDiscovererInfo GstDiscovererInfo;

Structure containing the information of a URI analyzed by GstDiscoverer.

### enum GstDiscovererResult

Result values for the discovery process.

#### Members

GST_DISCOVERER_OK | The discovery was successful |
GST_DISCOVERER_URI_INVALID | the URI is invalid |
GST_DISCOVERER_ERROR | an error happened and the GError is set |
GST_DISCOVERER_TIMEOUT | the discovery timed-out |
GST_DISCOVERER_BUSY | the discoverer was already discovering a file |
GST_DISCOVERER_MISSING_PLUGINS | Some plugins are missing for full discovery |

### GstDiscovererStreamInfo

    typedef struct _GstDiscovererStreamInfo GstDiscovererStreamInfo;

Base structure for information concerning a media stream. Depending on the stream type, one can find more media-specific information in GstDiscovererAudioInfo, GstDiscovererVideoInfo, and GstDiscovererContainerInfo.

The GstDiscovererStreamInfo represents the topology of the stream. Siblings can be iterated over with `gst_discoverer_stream_info_get_next()` and `gst_discoverer_stream_info_get_previous()`. Children (sub-streams) of a stream can be accessed using the GstDiscovererContainerInfo API.

As a simple example, if you run GstDiscoverer on an AVI file with one audio and one video stream, you will get a GstDiscovererContainerInfo corresponding to the AVI container, which in turn will have a GstDiscovererAudioInfo sub-stream and a GstDiscovererVideoInfo sub-stream for the audio and video streams respectively.

### GstDiscovererContainerInfo

    typedef struct _GstDiscovererContainerInfo GstDiscovererContainerInfo;

GstDiscovererStreamInfo specific to container streams.

### GstDiscovererAudioInfo

    typedef struct _GstDiscovererAudioInfo GstDiscovererAudioInfo;

GstDiscovererStreamInfo specific to audio streams.

### GstDiscovererVideoInfo

    typedef struct _GstDiscovererVideoInfo GstDiscovererVideoInfo;

GstDiscovererStreamInfo specific to video streams (this includes images).

### GstDiscovererSubtitleInfo

    typedef struct _GstDiscovererSubtitleInfo GstDiscovererSubtitleInfo;

GstDiscovererStreamInfo specific to subtitle streams (this includes text and image based ones).

## Property Details

### The `“timeout”` property

      “timeout”                  guint64

The duration (in nanoseconds) after which the discovery of an individual URI will timeout.

If the discovery of a URI times out, the `GST_DISCOVERER_TIMEOUT` will be set on the result flags.

Flags: Read / Write / Construct

Allowed values: [1000000000,3600000000000]

Default value: 15000000000

## Signal Details

### The `“discovered”` signal

    void
    user_function (GstDiscoverer     *discoverer,
                   GstDiscovererInfo *info,
                   GError            *error,
                   gpointer           user_data)

Will be emitted in async mode when all information on a URI could be discovered, or an error occurred.

When an error occurs, `info` might still contain some partial information, depending on the circumstances of the error.

#### Parameters

discoverer | the GstDiscoverer |
info | the results GstDiscovererInfo |
error | GError, which will be non-NULL if an error occurred during discovery. You must not free this GError, it will be freed by the discoverer. | [type GLib.Error]
user_data | user data set when the signal handler was connected. |

Flags: Run Last

### The `“finished”` signal

    void
    user_function (GstDiscoverer *discoverer,
                   gpointer       user_data)

Will be emitted in async mode when all pending URIs have been processed.

#### Parameters

discoverer | the GstDiscoverer |
user_data | user data set when the signal handler was connected. |

Flags: Run Last

### The `“source-setup”` signal

    void
    user_function (GstDiscoverer *discoverer,
                   GstElement    *source,
                   gpointer       user_data)

This signal is emitted after the source element has been created for, so the URI being discovered, so it can be configured by setting additional properties (e.g. set a proxy server for an http source, or set the device and read speed for an audio cd source).

This signal is usually emitted from the context of a GStreamer streaming thread.

#### Parameters

discoverer | the GstDiscoverer |
source | source element |
user_data | user data set when the signal handler was connected. |

Flags: Run Last

### The `“starting”` signal

    void
    user_function (GstDiscoverer *discoverer,
                   gpointer       user_data)

Will be emitted when the discover starts analyzing the pending URIs

#### Parameters

discoverer | the GstDiscoverer |
user_data | user data set when the signal handler was connected. |

Flags: Run Last