Delayed creation of audio effect object until audio is initialized

When applying effects to an audio stream, we must ensure that the MMF
utility API (CMdaAudioPlayerUtility or CVideoPlayerUtility) instance has
loaded a controller before calling attempting to create a CAudioEffect-
derived object.  If the controller has not been loaded, construction of
the effect object will fail.  Even if we mitigate against this, calling
CAudioEffect::ApplyL() will only have an effect if there is a controller
object - or more precisely, a DevSound instance - on which to apply the
effect.

This patch delays construction of the effect object until the MediaObject
has transitioned out of the LoadingState, indicating that an underlying
DevSound instance will have been created.

Task-number: QTBUG-4659
Reviewed-by: Espen Riskedal

1 files changed, 10 insertions, 1 deletions

diff --git a/src/3rdparty/phonon/mmf/abstractaudioeffect.h b/src/3rdparty/phonon/mmf/abstractaudioeffect.h
index 4772eb8..7d44bf0 100644
--- a/src/3rdparty/phonon/mmf/abstractaudioeffect.h
+++ b/src/3rdparty/phonon/mmf/abstractaudioeffect.h
@@ -36,6 +36,7 @@ namespace Phonon
 {
 namespace MMF
 {
+class AbstractPlayer;
 class AbstractMediaPlayer;
 
 /**
@@ -69,17 +70,25 @@ public:
     virtual void setParameterValue(const Phonon::EffectParameter &,
                                    const QVariant &newValue);
 
+public Q_SLOTS:
+    void abstractPlayerChanged(AbstractPlayer *player);
+    void stateChanged(Phonon::State newState,
+                      Phonon::State oldState);
+
 protected:
     // MediaNode
     void connectMediaObject(MediaObject *mediaObject);
     void disconnectMediaObject(MediaObject *mediaObject);
 
-    virtual void connectAudioPlayer(AudioPlayer::NativePlayer *player) = 0;
+    virtual void createEffect(AudioPlayer::NativePlayer *player) = 0;
     virtual void applyParameters() = 0;
 
     virtual void parameterChanged(const int id,
                                   const QVariant &value) = 0;
 
+private:
+    void createEffect();
+
 protected:
     QScopedPointer<CAudioEffect>    m_effect;
     const QList<EffectParameter>    m_params;