BtSong

BtSong — class of a song project object (contains BtSongInfo, BtSetup, BtSequence and BtWavetable)

Functions

gboolean bt_song_continue ()
BtSong * bt_song_new ()
gboolean bt_song_pause ()
gboolean bt_song_play ()
gboolean bt_song_stop ()
gboolean bt_song_update_playback_position ()

Properties

BtApplication * app Read / Write / Construct Only
GstBin * bin Read
gboolean is-idle Read / Write
gboolean is-playing Read
BtSinkMachine * master Read / Write
gulong play-pos Read / Write
gdouble play-rate Read / Write
BtSequence * sequence Read
BtSetup * setup Read
BtSongInfo * song-info Read
BtSongIO * song-io Read / Write
BtWavetable * wavetable Read

Types and Values

struct BtSong
struct BtSongClass

Object Hierarchy

    GObject
    ╰── BtSong

Implemented Interfaces

BtSong implements BtPersistence.

Includes

#include <libbtcore/core.h>

Description

A song is the top-level container object to manage all song-related objects. The BtSetup contains the machines and their connections, the BtSequence contains the overall time-line, the BtWavetable holds a list of audio snippets and the BtSongInfo has a couple of meta-data items for the song.

To load or save a song, use a BtSongIO object. These implement loading and saving for different file-formats.

One can seek in a song by setting the “play-pos” property. Likewise one can watch the property to display the playback position.

The “play-rate” property can be used to change the playback speed and direction.

Functions

bt_song_continue ()

gboolean
bt_song_continue (const BtSong * const self);

Continues the playback of the specified song instance.

Parameters

self

the song that should be paused

 

Returns

TRUE for success


bt_song_new ()

BtSong *
bt_song_new (const BtApplication * const app);

Create a new instance. The new song instance automatically has one instance of BtSetup, BtSequence and BtSongInfo. These instances can be retrieved via the respecting properties.

For example use following code to retrive a BtSequence from the song class:

1
2
3
BtSequence *sequence;
...
g_object_get(BT_SONG(song), "sequence", &sequence, NULL);

Parameters

app

the application object the songs belongs to.

 

Returns

the new instance or NULL in case of an error


bt_song_pause ()

gboolean
bt_song_pause (const BtSong * const self);

Pauses the playback of the specified song instance.

Parameters

self

the song that should be paused

 

Returns

TRUE for success


bt_song_play ()

gboolean
bt_song_play (const BtSong * const self);

Starts to play the specified song instance from beginning. This methods toggles the “is-playing” property.

Parameters

self

the song that should be played

 

Returns

TRUE for success


bt_song_stop ()

gboolean
bt_song_stop (const BtSong * const self);

Stops the playback of the specified song instance.

Parameters

self

the song that should be stopped

 

Returns

TRUE for success


bt_song_update_playback_position ()

gboolean
bt_song_update_playback_position (const BtSong * const self);

Updates the playback-position counter to fire all “play-pos” notify handlers.

Parameters

self

the song that should update its playback-pos counter

 

Returns

FALSE if the song is not playing

Types and Values

struct BtSong

struct BtSong;

Song project object (contains BtSongInfo, BtSetup and BtSequence)


struct BtSongClass

struct BtSongClass {
  const GObjectClass parent;
};

Base class for songs

Members

const GObjectClass parent;

parent class type

 

Property Details

The “app” property

  “app”                      BtApplication *

set application object, the song belongs to.

Flags: Read / Write / Construct Only


The “bin” property

  “bin”                      GstBin *

songs top-level GstElement container.

Flags: Read


The “is-idle” property

  “is-idle”                  gboolean

request that the song should idle-loop if not playing.

Flags: Read / Write

Default value: FALSE


The “is-playing” property

  “is-playing”               gboolean

tell whether the song is playing right now or not.

Flags: Read

Default value: FALSE


The “master” property

  “master”                   BtSinkMachine *

songs audio_sink.

Flags: Read / Write


The “play-pos” property

  “play-pos”                 gulong

position of the play cursor of the sequence in timeline bars.

Flags: Read / Write

Allowed values: <= G_MAXLONG


The “play-rate” property

  “play-rate”                gdouble

playback rate of the sequence.

Flags: Read / Write

Allowed values: [-5,5]

Default value: 1


The “sequence” property

  “sequence”                 BtSequence *

songs sequence sub object.

Flags: Read


The “setup” property

  “setup”                    BtSetup *

songs setup sub object.

Flags: Read


The “song-info” property

  “song-info”                BtSongInfo *

songs metadata sub object.

Flags: Read


The “song-io” property

  “song-io”                  BtSongIO *

the song-io plugin during i/o operations.

Flags: Read / Write


The “wavetable” property

  “wavetable”                BtWavetable *

songs wavetable sub object.

Flags: Read