diff audio/ClipMixer.h @ 468:56acd9368532 bqaudioio

Initial work toward switching to bqaudioio library (so as to get I/O, not just O)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/audio/ClipMixer.h	Tue Aug 04 13:27:42 2015 +0100
@@ -0,0 +1,94 @@
+/* -*- 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 file copyright 2006 Chris Cannam, 2006-2014 QMUL.
+    
+    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 CLIP_MIXER_H
+#define CLIP_MIXER_H
+
+#include <QString>
+#include <vector>
+
+#include "base/BaseTypes.h"
+
+/**
+ * Mix in synthetic notes produced by resampling a prerecorded
+ * clip. (i.e. this is an implementation of a digital sampler in the
+ * musician's sense.) This can mix any number of notes of arbitrary
+ * frequency, so long as they all use the same sample clip.
+ */
+
+class ClipMixer
+{
+public:
+    ClipMixer(int channels, sv_samplerate_t sampleRate, sv_frame_t blockSize);
+    ~ClipMixer();
+
+    void setChannelCount(int channels);
+
+    /**
+     * Load a sample clip from a wav file. This can only happen once:
+     * construct a new ClipMixer if you want a different clip. The
+     * clip was recorded at a pitch with fundamental frequency clipF0,
+     * and should be scaled by level (in the range 0-1) when playing
+     * back.
+     */
+    bool loadClipData(QString clipFilePath, double clipF0, double level);
+
+    void reset(); // discarding any playing notes
+
+    struct NoteStart {
+	sv_frame_t frameOffset; // within current processing block
+	float frequency; // Hz
+	float level; // volume in range (0,1]
+	float pan; // range [-1,1]
+    };
+
+    struct NoteEnd {
+	sv_frame_t frameOffset; // in current processing block
+        float frequency; // matching note start
+    };
+
+    void mix(float **toBuffers, 
+             float gain,
+	     std::vector<NoteStart> newNotes, 
+	     std::vector<NoteEnd> endingNotes);
+
+private:
+    int m_channels;
+    sv_samplerate_t m_sampleRate;
+    sv_frame_t m_blockSize;
+
+    QString m_clipPath;
+
+    float *m_clipData;
+    sv_frame_t m_clipLength;
+    double m_clipF0;
+    sv_samplerate_t m_clipRate;
+
+    std::vector<NoteStart> m_playing;
+
+    double getResampleRatioFor(double frequency);
+    sv_frame_t getResampledClipDuration(double frequency);
+
+    void mixNote(float **toBuffers, 
+                 float *levels,
+                 float frequency,
+                 sv_frame_t sourceOffset, // within resampled note
+                 sv_frame_t targetOffset, // within target buffer
+                 sv_frame_t sampleCount,
+                 bool isEnd);
+};
+
+
+#endif