Optimise audio filters; tweak order of the LPFs in the upmixers.

4 files changed, 34 insertions, 17 deletions

diff --git a/src/lib/audio_filter.cc b/src/lib/audio_filter.cc
index 10f3849df..2c92236b6 100644
--- a/src/lib/audio_filter.cc
+++ b/src/lib/audio_filter.cc
@@ -21,14 +21,14 @@
 #include "audio_buffers.h"
 #include <cmath>
 
-using std::vector;
 using std::min;
 using boost::shared_ptr;
 
-vector<float>
+/** @return array of floats which the caller must destroy with delete[] */
+float *
 AudioFilter::sinc_blackman (float cutoff, bool invert) const
 {
-	vector<float> ir (_M + 1);
+	float* ir = new float[_M + 1];
 
 	/* Impulse response */
 
@@ -66,6 +66,11 @@ AudioFilter::sinc_blackman (float cutoff, bool invert) const
 	return ir;
 }
 
+AudioFilter::~AudioFilter ()
+{
+	delete[] _ir;
+}
+
 shared_ptr<AudioBuffers>
 AudioFilter::run (shared_ptr<const AudioBuffers> in)
 {
@@ -76,18 +81,24 @@ AudioFilter::run (shared_ptr<const AudioBuffers> in)
 		_tail->make_silent ();
 	}
 
-	for (int i = 0; i < in->channels(); ++i) {
-		for (int j = 0; j < in->frames(); ++j) {
+	int const channels = in->channels ();
+	int const frames = in->frames ();
+
+	for (int i = 0; i < channels; ++i) {
+		float* tail_p = _tail->data (i);
+		float* in_p = in->data (i);
+		float* out_p = out->data (i);
+		for (int j = 0; j < frames; ++j) {
 			float s = 0;
 			for (int k = 0; k <= _M; ++k) {
 				if ((j - k) < 0) {
-					s += _tail->data(i)[j - k + _M + 1] * _ir[k];
+					s += tail_p[j - k + _M + 1] * _ir[k];
 				} else {
-					s += in->data(i)[j - k] * _ir[k];
+					s += in_p[j - k] * _ir[k];
 				}
 			}
 
-			out->data(i)[j] = s;
+			out_p[j] = s;
 		}
 	}
 
@@ -122,14 +133,18 @@ HighPassAudioFilter::HighPassAudioFilter (float transition_bandwidth, float cuto
 BandPassAudioFilter::BandPassAudioFilter (float transition_bandwidth, float lower, float higher)
 	: AudioFilter (transition_bandwidth)
 {
-	vector<float> lpf = sinc_blackman (lower, false);
-	vector<float> hpf = sinc_blackman (higher, true);
+	float* lpf = sinc_blackman (lower, false);
+	float* hpf = sinc_blackman (higher, true);
 
-	_ir.resize (_M + 1);
+	delete[] _ir;
+	_ir = new float[_M + 1];
 	for (int i = 0; i <= _M; ++i) {
 		_ir[i] = lpf[i] + hpf[i];
 	}
 
+	delete[] lpf;
+	delete[] hpf;
+
 	/* We now have a band-stop, so invert for band-pass */
 	for (int i = 0; i <= _M; ++i) {
 		_ir[i] = -_ir[i];
diff --git a/src/lib/audio_filter.h b/src/lib/audio_filter.h
index 640e910ca..912e8c210 100644
--- a/src/lib/audio_filter.h
+++ b/src/lib/audio_filter.h
@@ -21,7 +21,6 @@
 #define DCPOMATIC_AUDIO_FILTER_H
 
 #include <boost/shared_ptr.hpp>
-#include <vector>
 
 class AudioBuffers;
 struct audio_filter_impulse_input_test;
@@ -30,6 +29,7 @@ class AudioFilter
 {
 public:
 	AudioFilter (float transition_bandwidth)
+		: _ir (0)
 	{
 		_M = 4 / transition_bandwidth;
 		if (_M % 2) {
@@ -37,6 +37,8 @@ public:
 		}
 	}
 
+	virtual ~AudioFilter ();
+
 	boost::shared_ptr<AudioBuffers> run (boost::shared_ptr<const AudioBuffers> in);
 
 	void flush ();
@@ -45,9 +47,9 @@ protected:
 	friend struct audio_filter_impulse_kernel_test;
 	friend struct audio_filter_impulse_input_test;
 
-	std::vector<float> sinc_blackman (float cutoff, bool invert) const;
+	float* sinc_blackman (float cutoff, bool invert) const;
 
-	std::vector<float> _ir;
+	float* _ir;
 	int _M;
 	boost::shared_ptr<AudioBuffers> _tail;
 };
diff --git a/src/lib/upmixer_a.cc b/src/lib/upmixer_a.cc
index 3cbb995ef..a01ff30bb 100644
--- a/src/lib/upmixer_a.cc
+++ b/src/lib/upmixer_a.cc
@@ -31,8 +31,8 @@ using boost::shared_ptr;
 UpmixerA::UpmixerA (int sampling_rate)
 	: _left (0.02, 1900.0 / sampling_rate, 4800.0 / sampling_rate)
 	, _right (0.02, 1900.0 / sampling_rate, 4800.0 / sampling_rate)
-	, _centre (0.002, 150.0 / sampling_rate, 1900.0 / sampling_rate)
-	, _lfe (0.002, 150.0 / sampling_rate)
+	, _centre (0.01, 150.0 / sampling_rate, 1900.0 / sampling_rate)
+	, _lfe (0.01, 150.0 / sampling_rate)
 	, _ls (0.02, 4800.0 / sampling_rate, 20000.0 / sampling_rate)
 	, _rs (0.02, 4800.0 / sampling_rate, 20000.0 / sampling_rate)
 {
diff --git a/src/lib/upmixer_b.cc b/src/lib/upmixer_b.cc
index 19f0dfed1..9408fdf83 100644
--- a/src/lib/upmixer_b.cc
+++ b/src/lib/upmixer_b.cc
@@ -29,7 +29,7 @@ using std::vector;
 using boost::shared_ptr;
 
 UpmixerB::UpmixerB (int sampling_rate)
-	: _lfe (0.002, 150.0 / sampling_rate)
+	: _lfe (0.01, 150.0 / sampling_rate)
 	, _delay (0.02 * sampling_rate)
 {