libvlc: expose event for audio volume change (fixes #14568)

Cc: Harald Sitter <sitter@kde.org>

include/vlc/libvlc_events.h

@@ -81,6 +81,7 @@ enum libvlc_event_e {
     libvlc_MediaPlayerUncorked,
     libvlc_MediaPlayerMuted,
     libvlc_MediaPlayerUnmuted,
+    libvlc_MediaPlayerAudioVolume,
 
     libvlc_MediaListItemAdded=0x200,
     libvlc_MediaListWillAddItem,
@@ -244,6 +245,11 @@ typedef struct libvlc_event_t
             libvlc_track_type_t i_type;
             int                 i_id;
         } media_player_es_changed;
+
+        struct
+        {
+            float volume;
+        } media_player_audio_volume;
     } u; /**< Type-dependent event description */
 } libvlc_event_t;
 

lib/event.c

@@ -287,6 +287,7 @@ static const event_name_t event_list[] = {
     DEF(MediaPlayerUncorked)
     DEF(MediaPlayerMuted)
     DEF(MediaPlayerUnmuted)
+    DEF(MediaPlayerAudioVolume)
 
     DEF(MediaListItemAdded)
     DEF(MediaListWillAddItem)

lib/media_player.c

@@ -75,6 +75,10 @@ static int
 mute_changed(vlc_object_t *obj, const char *name, vlc_value_t old,
              vlc_value_t cur, void *opaque);
 
+static int
+volume_changed(vlc_object_t *obj, const char *name, vlc_value_t old,
+               vlc_value_t cur, void *opaque);
+
 static void
 add_es_callbacks( input_thread_t *p_input_thread, libvlc_media_player_t *p_mi );
 
@@ -504,6 +508,19 @@ static int mute_changed(vlc_object_t *obj, const char *name, vlc_value_t old,
     return VLC_SUCCESS;
 }
 
+static int volume_changed(vlc_object_t *obj, const char *name, vlc_value_t old,
+                          vlc_value_t cur, void *opaque)
+{
+    libvlc_media_player_t *mp = (libvlc_media_player_t *)obj;
+    libvlc_event_t event;
+
+    event.type = libvlc_MediaPlayerAudioVolume;
+    event.u.media_player_audio_volume.volume = cur.f_float;
+    libvlc_event_send(mp->p_event_manager, &event);
+    VLC_UNUSED(name); VLC_UNUSED(old); VLC_UNUSED(opaque);
+    return VLC_SUCCESS;
+}
+
 /**************************************************************************
  * Create a Media Instance object.
  *
@@ -683,9 +700,11 @@ libvlc_media_player_new( libvlc_instance_t *instance )
     register_event(mp, Uncorked);
     register_event(mp, Muted);
     register_event(mp, Unmuted);
+    register_event(mp, AudioVolume);
 
     var_AddCallback(mp, "corks", corks_changed, NULL);
     var_AddCallback(mp, "mute", mute_changed, NULL);
+    var_AddCallback(mp, "volume", volume_changed, NULL);
 
     /* Snapshot initialization */
     register_event(mp, SnapshotTaken);
@@ -737,6 +756,7 @@ static void libvlc_media_player_destroy( libvlc_media_player_t *p_mi )
                      "snapshot-file", snapshot_was_taken, p_mi );
 
     /* Detach callback from the media player / input manager object */
+    var_DelCallback( p_mi, "volume", volume_changed, NULL );
     var_DelCallback( p_mi, "mute", mute_changed, NULL );
     var_DelCallback( p_mi, "corks", corks_changed, NULL );