Work on extending the framework for accomodating effects.

This extends the framework for being able to handle audio effects, largely
affecting how the audio chain is set up, connected and disconnected, and
therefore the Backend has been refactored slightly, and the class MediaNode
introduced, see its documentation.

In addition two effects has been written: BassBoost and AudioEqualizer.

1 files changed, 108 insertions, 0 deletions

diff --git a/src/3rdparty/phonon/mmf/abstractaudioeffect.h b/src/3rdparty/phonon/mmf/abstractaudioeffect.h
new file mode 100644
index 0000000..4c2eba3
--- /dev/null
+++ b/src/3rdparty/phonon/mmf/abstractaudioeffect.h
@@ -0,0 +1,108 @@
+/*  This file is part of the KDE project.
+
+Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+
+This library is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation, either version 2.1 or 3 of the License.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#ifndef PHONON_MMF_ABSTRACTEFFECT_H
+#define PHONON_MMF_ABSTRACTEFFECT_H
+
+#include "mmf_medianode.h"
+
+#include <QScopedPointer>
+
+#include <Phonon/EffectInterface>
+#include <Phonon/EffectParameter>
+#include "audioplayer.h"
+
+class CAudioEffect;
+
+QT_BEGIN_NAMESPACE
+
+namespace Phonon
+{
+namespace MMF
+{
+
+/**
+ * @short Base class for all effects for MMF.
+ *
+ * Adhering to Phonon with MMF is cumbersome because of a number of reasons:
+ *
+ * - MMF has no concept of effect chaining. Simply, an effect is a applied
+ *   to PlayerUtility, that's it. This means that the order of effects is
+ *   undefined.
+ * - We apply an effect to a PlayerUtility, and MediaObject has that one.
+ *   However, effects might be created before MediaObject, but nevertheless
+ *   needs to work. We solve this by that we are aware of the whole connection
+ *   chain, and whenever a connection happens, we walk the chain, find effects
+ *   that aren't applied, and apply it if we have a media object.
+ * - There are plenty of corner cases which we don't handle and where behavior
+ *   are undefined. For instance, graphs with more than one MediaObject.
+ */
+class AbstractAudioEffect : public MediaNode
+                          , public EffectInterface
+{
+    Q_OBJECT
+    Q_INTERFACES(Phonon::EffectInterface)
+public:
+    AbstractAudioEffect(QObject *parent,
+                        const QList<EffectParameter> &params);
+
+    virtual QList<EffectParameter> parameters() const;
+    virtual QVariant parameterValue(const EffectParameter &param) const;
+    virtual void setParameterValue(const EffectParameter &,
+                                   const QVariant &newValue);
+
+    virtual bool connectMediaNode(MediaNode *target);
+    virtual bool disconnectMediaNode(MediaNode *target);
+
+    enum Type
+    {
+        EffectAudioEqualizer = 1,
+        EffectBassBoost,
+        EffectDistanceAttenuation,
+        EffectEnvironmentalReverb,
+        EffectListenerOrientation,
+        EffectLoudness,
+        //EffectRoomLevel,
+        EffectSourceOrientation,
+        EffectStereoWidening
+    };
+
+protected:
+    virtual void activateOn(CPlayerType *player) = 0;
+    virtual void parameterChanged(const int id,
+                                  const QVariant &value) = 0;
+
+    QScopedPointer<CAudioEffect>    m_effect;
+private:
+    /**
+     * From @p target, we walk the chain backwards and try to find the media
+     * object, and apply ourselves to that one.
+     */
+    bool activateBackwardsInChain(MediaNode *target);
+
+    const QList<EffectParameter>    m_params;
+    bool                            m_isApplied;
+    QHash<int, QVariant>            m_values;
+};
+}
+}
+
+QT_END_NAMESPACE
+
+#endif
+