diff dsp/rateconversion/Resampler.h @ 137:dce8337a83c8

First cut at resampler (not quite correct)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dsp/rateconversion/Resampler.h	Fri Oct 11 18:00:51 2013 +0100
@@ -0,0 +1,58 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+#ifndef RESAMPLER_H
+#define RESAMPLER_H
+
+#include <vector>
+
+class Resampler
+{
+public:
+    /**
+     * Construct a Resampler to resample from sourceRate to
+     * targetRate.
+     */
+    Resampler(int sourceRate, int targetRate);
+    virtual ~Resampler();
+
+    /**
+     * Read n input samples from src and write resampled data to
+     * dst. The return value is the number of samples written, which
+     * will be no more than ceil((n * targetRate) / sourceRate). The
+     * caller must ensure the dst buffer has enough space for the
+     * samples returned.
+     */
+    int process(const double *src, double *dst, int n);
+
+    /**
+     * Return the number of samples of latency at the output due by
+     * the filter. (That is, the output will be delayed by this number
+     * of samples relative to the input.)
+     */
+    int getLatency() const { return m_latency; }
+
+private:
+    int m_sourceRate;
+    int m_targetRate;
+    int m_gcd;
+    int m_filterLength;
+    int m_bufferLength;
+    int m_latency;
+    
+    struct Phase {
+        int nextPhase;
+        std::vector<double> filter;
+        int drop;
+        int take;
+    };
+
+    Phase *m_phaseData;
+    int m_phase;
+    double *m_buffer;
+
+    void initialise();
+    double reconstructOne(const double **);
+};
+
+#endif
+