X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=libs%2Fardour%2Finterpolation.cc;h=286030c26db487cb8d825d0bd712119d3be9116a;hb=d92686afb4105b84b014372b6feb0ccc454a5171;hp=bccaa45553484bb0eceb9e82eeb6b578a3b174a4;hpb=ff9e1dfe602ab7b54d49849373fb2ce265c4f4a0;p=ardour.git

diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc
index bccaa45553..286030c26d 100644
--- a/libs/ardour/interpolation.cc
+++ b/libs/ardour/interpolation.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012 Paul Davis 
+    Copyright (C) 2012 Paul Davis
 
     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
@@ -21,6 +21,7 @@
 #include <cstdio>
 
 #include "ardour/interpolation.h"
+#include "ardour/midi_buffer.h"
 
 using namespace ARDOUR;
 
@@ -47,7 +48,7 @@ LinearInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input
 		}
 
 		if (input && output) {
-		// Linearly interpolate into the output buffer
+			// Linearly interpolate into the output buffer
 			output[outsample] =
 				input[i] * (1.0f - fractional_phase_part) +
 				input[i+1] * fractional_phase_part;
@@ -63,90 +64,127 @@ LinearInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input
 framecnt_t
 CubicInterpolation::interpolate (int channel, framecnt_t nframes, Sample *input, Sample *output)
 {
-    // index in the input buffers
-    framecnt_t   i = 0;
+	// index in the input buffers
+	framecnt_t   i = 0;
+
+	double acceleration;
+	double distance = 0.0;
 
-    double acceleration;
-    double distance = 0.0;
+	if (_speed != _target_speed) {
+		acceleration = _target_speed - _speed;
+	} else {
+		acceleration = 0.0;
+	}
 
-    if (_speed != _target_speed) {
-        acceleration = _target_speed - _speed;
-    } else {
-	    acceleration = 0.0;
-    }
+	distance = phase[channel];
 
-    distance = phase[channel];
+	if (nframes < 3) {
+		/* no interpolation possible */
 
-    if (nframes < 3) {
-	    /* no interpolation possible */
+		if (input && output) {
+			for (i = 0; i < nframes; ++i) {
+				output[i] = input[i];
+			}
+		}
+
+		return nframes;
+	}
 
-	    for (i = 0; i < nframes; ++i) {
-		    output[i] = input[i];
-	    }
+	/* keep this condition out of the inner loop */
 
-	    return nframes;
-    }
+	if (input && output) {
 
-    /* keep this condition out of the inner loop */
+		Sample inm1;
 
-    if (input && output) {
+		if (floor (distance) == 0.0) {
+			/* best guess for the fake point we have to add to be able to interpolate at i == 0:
+			   .... maintain slope of first actual segment ...
+			   */
+			inm1 = input[i] - (input[i+1] - input[i]);
+		} else {
+			inm1 = input[i-1];
+		}
 
-	    Sample inm1;
+		for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
 
-	    if (floor (distance) == 0.0) {
-		    /* best guess for the fake point we have to add to be able to interpolate at i == 0:
-		       .... maintain slope of first actual segment ...
-		    */
-		    inm1 = input[i] - (input[i+1] - input[i]);
-	    } else {
-		    inm1 = input[i-1];
-	    }
+			float f = floor (distance);
+			float fractional_phase_part = distance - f;
 
-	    for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+			/* get the index into the input we should start with */
 
-		    float f = floor (distance);
-		    float fractional_phase_part = distance - f;
+			i = lrintf (f);
 
-		    /* get the index into the input we should start with */
+			/* fractional_phase_part only reaches 1.0 thanks to float imprecision. In theory
+			   it should always be < 1.0. If it ever >= 1.0, then bump the index we use
+			   and back it off. This is the point where we "skip" an entire sample in the
+			   input, because the phase part has accumulated so much error that we should
+			   really be closer to the next sample. or something like that ...
+			   */
 
-		    i = lrintf (f);
+			if (fractional_phase_part >= 1.0) {
+				fractional_phase_part -= 1.0;
+				++i;
+			}
 
-		    /* fractional_phase_part only reaches 1.0 thanks to float imprecision. In theory
-		       it should always be < 1.0. If it ever >= 1.0, then bump the index we use
-		       and back it off. This is the point where we "skip" an entire sample in the
-		       input, because the phase part has accumulated so much error that we should
-		       really be closer to the next sample. or something like that ...
-		    */
+			// Cubically interpolate into the output buffer: keep this inlined for speed and rely on compiler
+			// optimization to take care of the rest
+			// shamelessly ripped from Steve Harris' swh-plugins (ladspa-util.h)
 
-		    if (fractional_phase_part >= 1.0) {
-			    fractional_phase_part -= 1.0;
-			    ++i;
-		    }
+			output[outsample] = input[i] + 0.5f * fractional_phase_part * (input[i+1] - inm1 +
+					fractional_phase_part * (4.0f * input[i+1] + 2.0f * inm1 - 5.0f * input[i] - input[i+2] +
+						fractional_phase_part * (3.0f * (input[i] - input[i+1]) - inm1 + input[i+2])));
 
-		    // Cubically interpolate into the output buffer: keep this inlined for speed and rely on compiler
-		    // optimization to take care of the rest
-		    // shamelessly ripped from Steve Harris' swh-plugins (ladspa-util.h)
+			distance += _speed + acceleration;
+			inm1 = input[i];
+		}
 
-		    output[outsample] = input[i] + 0.5f * fractional_phase_part * (input[i+1] - inm1 +
-							  fractional_phase_part * (4.0f * input[i+1] + 2.0f * inm1 - 5.0f * input[i] - input[i+2] +
-								fractional_phase_part * (3.0f * (input[i] - input[i+1]) - inm1 + input[i+2])));
+		i = floor(distance);
+		phase[channel] = distance - floor(distance);
 
-		    distance += _speed + acceleration;
-		    inm1 = input[i];
-	    }
+	} else {
+		/* used to calculate play-distance with acceleration (silent roll)
+		 * (use same algorithm as real playback for identical rounding/floor'ing)
+		 */
+		for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+			distance += _speed + acceleration;
+		}
+		i = floor(distance);
+	}
 
-	    i = floor(distance);
-	    phase[channel] = distance - floor(distance);
+	return i;
+}
 
-    } else {
-	    /* used to calculate play-distance with acceleration (silent roll)
-	     * (use same algorithm as real playback for identical rounding/floor'ing)
-	     */
-	    for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
-		    distance += _speed + acceleration;
-	    }
-	    i = floor(distance);
-    }
+framecnt_t
+CubicMidiInterpolation::distance (framecnt_t nframes, bool roll)
+{
+	assert(phase.size() == 1);
 
-    return i;
+	framecnt_t i = 0;
+
+	double acceleration;
+	double distance = 0.0;
+
+	if (nframes < 3) {
+		return nframes;
+	}
+
+	if (_speed != _target_speed) {
+		acceleration = _target_speed - _speed;
+	} else {
+		acceleration = 0.0;
+	}
+
+	distance = phase[0];
+
+	for (framecnt_t outsample = 0; outsample < nframes; ++outsample) {
+		distance += _speed + acceleration;
+	}
+
+	if (roll) {
+		phase[0] = distance - floor(distance);
+	}
+
+	i = floor(distance);
+
+	return i;
 }