From f42f577bedbffcd2465341e033afac0a0326a491 Mon Sep 17 00:00:00 2001
From: Hans Baier <hansfbaier@googlemail.com>
Date: Tue, 23 Jun 2009 09:50:02 +0000
Subject: Interpolation: First working but buggy version using libsamplerate

git-svn-id: svn://localhost/ardour2/branches/3.0@5255 d708f5d6-7413-0410-9779-e7cbd77b26cf
---
 libs/ardour/interpolation.cc | 93 ++++++++++++++++++++++++++++++--------------
 1 file changed, 64 insertions(+), 29 deletions(-)

(limited to 'libs/ardour/interpolation.cc')

diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc
index 066507283b..a4a4b08872 100644
--- a/libs/ardour/interpolation.cc
+++ b/libs/ardour/interpolation.cc
@@ -1,41 +1,76 @@
 #include <stdint.h>
+
 #include "ardour/interpolation.h"
 
 using namespace ARDOUR;
 
-nframes_t
-LinearInterpolation::interpolate (nframes_t nframes, Sample *input, Sample *output)
+Interpolation::Interpolation()  : _speed (1.0L), state (0)
+{
+}
+
+Interpolation::~Interpolation() 
+{
+	state = src_delete (state);
+}
+
+void
+Interpolation::set_speed (double new_speed)
+{ 
+	_speed = new_speed; 
+	src_set_ratio (state, 1.0/_speed); 
+}
+
+void
+Interpolation::reset_state ()
+{
+	if (state) {
+		src_reset (state);
+	} else {
+		state = src_new (SRC_LINEAR, 1, &error);
+	}
+}
+
+void
+Interpolation::add_channel_to (int input_buffer_size, int output_buffer_size) 
 {
-	// the idea is that when the speed is not 1.0, we have to 
-	// interpolate between samples and then we have to store where we thought we were. 
-	// rather than being at sample N or N+1, we were at N+0.8792922
+	SRC_DATA newdata;
 	
-	// index in the input buffers
-	nframes_t   i = 0;
+	/* Set up sample rate converter info. */
+	newdata.end_of_input = 0 ; 
+
+	newdata.input_frames  = input_buffer_size;
+	newdata.output_frames = output_buffer_size;
+
+	newdata.input_frames_used = 0 ;
+	newdata.output_frames_gen = 0 ;
+
+	newdata.src_ratio = 1.0/_speed;
 	
-	double acceleration;
-	double distance = 0.0;
+	data.push_back (newdata);
 	
-	if (_speed != _target_speed) {
-		acceleration = _target_speed - _speed;
-	} else {
-		acceleration = 0.0;
-	}
+	reset_state ();
+}
 
-	for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
-		i = distance;
-		Sample fractional_phase_part = distance - i;
-		
-		if (input && output) {
-	        // Linearly interpolate into the output buffer
-			output[outsample] = 
-				input[i] * (1.0f - fractional_phase_part) +
-				input[i+1] * fractional_phase_part;
-		}
-		distance   += _speed + acceleration;
-	}
+void
+Interpolation::remove_channel_from () 
+{
+	data.pop_back ();
+	reset_state ();
+}
+
+nframes_t
+Interpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
+{	
+	data[channel].data_in       = input;
+	data[channel].data_out      = output;
 	
-	i = (distance + 0.5L);
-	// playback distance
-	return i;
+	data[channel].output_frames = nframes;
+	data[channel].src_ratio     = 1.0/_speed; 
+
+	if ((error = src_process (state, &data[channel]))) {	
+		printf ("\nError : %s\n\n", src_strerror (error));
+		exit (1);
+	}
+
+	return data[channel].input_frames_used;
 }
-- 
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