diff audio/EffectWrapper.h @ 739:ddfac001b543 audio-source-refactor

Introduce EffectWrapper for the auditioning effect

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/audio/EffectWrapper.h	Thu Mar 19 16:14:02 2020 +0000
@@ -0,0 +1,115 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef SV_EFFECT_WRAPPER_H
+#define SV_EFFECT_WRAPPER_H
+
+#include "bqaudioio/ApplicationPlaybackSource.h"
+
+#include "base/BaseTypes.h"
+#include "base/RingBuffer.h"
+
+#include "plugin/RealTimePluginInstance.h"
+
+#include <vector>
+#include <mutex>
+#include <memory>
+
+/**
+ * A breakfastquay::ApplicationPlaybackSource wrapper that applies a
+ * real-time effect plugin.
+ */
+class EffectWrapper : public breakfastquay::ApplicationPlaybackSource
+{
+public:
+    /**
+     * Create a wrapper around the given ApplicationPlaybackSource,
+     * implementing another ApplicationPlaybackSource interface that
+     * draws from the same source data but with an effect optionally
+     * applied.
+     *
+     * The wrapper does not take ownership of the wrapped
+     * ApplicationPlaybackSource, whose lifespan must exceed that of
+     * this object.    
+     */
+    EffectWrapper(ApplicationPlaybackSource *source);
+    ~EffectWrapper();
+
+    /**
+     * Set the effect to apply. The effect instance is shared with the
+     * caller: the expectation is that the caller may continue to
+     * modify its parameters etc during auditioning. Replaces any
+     * instance previously set.
+     */
+    void setEffect(std::weak_ptr<RealTimePluginInstance>);
+
+    /**
+     * Remove any applied effect without setting another one.
+     */
+    void clearEffect();
+
+    /**
+     * Bypass or un-bypass the effect.
+     */
+    void setBypassed(bool bypassed);
+
+    /**
+     * Return true if the effect is bypassed.
+     */
+    bool isBypassed() const;
+    
+    /**
+     * Clear any buffered data.
+     */
+    void reset();
+
+    // These functions are passed through to the wrapped
+    // ApplicationPlaybackSource
+    
+    std::string getClientName() const override;
+    int getApplicationSampleRate() const override;
+    int getApplicationChannelCount() const override;
+
+    void setSystemPlaybackBlockSize(int) override;
+    void setSystemPlaybackSampleRate(int) override;
+    void setSystemPlaybackChannelCount(int) override;
+    void setSystemPlaybackLatency(int) override;
+
+    void setOutputLevels(float peakLeft, float peakRight) override;
+    void audioProcessingOverload() override;
+
+    /** 
+     * Request some samples from the wrapped
+     * ApplicationPlaybackSource, apply effect if set, and return them
+     * to the target
+     */
+    int getSourceSamples(float *const *samples, int nchannels, int nframes)
+        override;
+
+private:
+    ApplicationPlaybackSource *m_source;
+    std::weak_ptr<RealTimePluginInstance> m_effect;
+    bool m_bypassed;
+    bool m_failed;
+    int m_channelCount;
+    std::vector<RingBuffer<float>> m_effectOutputBuffers;
+    mutable std::mutex m_mutex;
+
+    EffectWrapper(const EffectWrapper &)=delete;
+    EffectWrapper &operator=(const EffectWrapper &)=delete;
+};
+
+#endif
+
+