comparison src/portaudio_20140130/examples/paex_pink.c @ 124:e3d5853d5918

Current stable PortAudio source

+/** @file paex_pink.c
+	@ingroup examples_src
+	@brief Generate Pink Noise using Gardner method.
+
+	Optimization suggested by James McCartney uses a tree
+	to select which random value to replace.
+<pre>
+	x x x x x x x x x x x x x x x x 
+	x   x   x   x   x   x   x   x   
+	x       x       x       x       
+	 x               x               
+	   x   
+</pre>                            
+	Tree is generated by counting trailing zeros in an increasing index.
+	When the index is zero, no random number is selected.
+
+	@author Phil Burk  http://www.softsynth.com
+*/
+/*
+ * $Id: paex_pink.c 1752 2011-09-08 03:21:55Z philburk $
+ *
+ * This program uses the PortAudio Portable Audio Library.
+ * For more information see: http://www.portaudio.com
+ * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+ * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+ * The text above constitutes the entire PortAudio license; however, 
+ * the PortAudio community also makes the following non-binding requests:
+ *
+ * Any person wishing to distribute modifications to the Software is
+ * requested to send the modifications to the original developer so that
+ * they can be incorporated into the canonical version. It is also 
+ * requested that these non-binding requests be included along with the 
+ * license above.
+ */
+
+#include <stdio.h>
+#include <math.h>
+#include "portaudio.h"
+
+#define PINK_MAX_RANDOM_ROWS   (30)
+#define PINK_RANDOM_BITS       (24)
+#define PINK_RANDOM_SHIFT      ((sizeof(long)*8)-PINK_RANDOM_BITS)
+
+typedef struct
+{
+    long      pink_Rows[PINK_MAX_RANDOM_ROWS];
+    long      pink_RunningSum;   /* Used to optimize summing of generators. */
+    int       pink_Index;        /* Incremented each sample. */
+    int       pink_IndexMask;    /* Index wrapped by ANDing with this mask. */
+    float     pink_Scalar;       /* Used to scale within range of -1.0 to +1.0 */
+}
+PinkNoise;
+
+/* Prototypes */
+static unsigned long GenerateRandomNumber( void );
+void InitializePinkNoise( PinkNoise *pink, int numRows );
+float GeneratePinkNoise( PinkNoise *pink );
+
+/************************************************************/
+/* Calculate pseudo-random 32 bit number based on linear congruential method. */
+static unsigned long GenerateRandomNumber( void )
+{
+    /* Change this seed for different random sequences. */
+    static unsigned long randSeed = 22222;
+    randSeed = (randSeed * 196314165) + 907633515;
+    return randSeed;
+}
+
+/************************************************************/
+/* Setup PinkNoise structure for N rows of generators. */
+void InitializePinkNoise( PinkNoise *pink, int numRows )
+{
+    int i;
+    long pmax;
+    pink->pink_Index = 0;
+    pink->pink_IndexMask = (1<<numRows) - 1;
+    /* Calculate maximum possible signed random value. Extra 1 for white noise always added. */
+    pmax = (numRows + 1) * (1<<(PINK_RANDOM_BITS-1));
+    pink->pink_Scalar = 1.0f / pmax;
+    /* Initialize rows. */
+    for( i=0; i<numRows; i++ ) pink->pink_Rows[i] = 0;
+    pink->pink_RunningSum = 0;
+}
+
+#define PINK_MEASURE
+#ifdef PINK_MEASURE
+float pinkMax = -999.0;
+float pinkMin =  999.0;
+#endif
+
+/* Generate Pink noise values between -1.0 and +1.0 */
+float GeneratePinkNoise( PinkNoise *pink )
+{
+    long newRandom;
+    long sum;
+    float output;
+    /* Increment and mask index. */
+    pink->pink_Index = (pink->pink_Index + 1) & pink->pink_IndexMask;
+    /* If index is zero, don't update any random values. */
+    if( pink->pink_Index != 0 )
+    {
+        /* Determine how many trailing zeros in PinkIndex. */
+        /* This algorithm will hang if n==0 so test first. */
+        int numZeros = 0;
+        int n = pink->pink_Index;
+        while( (n & 1) == 0 )
+        {
+            n = n >> 1;
+            numZeros++;
+        }
+        /* Replace the indexed ROWS random value.
+         * Subtract and add back to RunningSum instead of adding all the random
+         * values together. Only one changes each time.
+         */
+        pink->pink_RunningSum -= pink->pink_Rows[numZeros];
+        newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;
+        pink->pink_RunningSum += newRandom;
+        pink->pink_Rows[numZeros] = newRandom;
+    }
+
+    /* Add extra white noise value. */
+    newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;
+    sum = pink->pink_RunningSum + newRandom;
+    /* Scale to range of -1.0 to 0.9999. */
+    output = pink->pink_Scalar * sum;
+#ifdef PINK_MEASURE
+    /* Check Min/Max */
+    if( output > pinkMax ) pinkMax = output;
+    else if( output < pinkMin ) pinkMin = output;
+#endif
+    return output;
+}
+
+/*******************************************************************/
+#define PINK_TEST
+#ifdef PINK_TEST
+
+/* Context for callback routine. */
+typedef struct
+{
+    PinkNoise   leftPink;
+    PinkNoise   rightPink;
+    unsigned int sampsToGo;
+}
+paTestData;
+
+/* This routine will be called by the PortAudio engine when audio is needed.
+** It may called at interrupt level on some machines so don't do anything
+** that could mess up the system like calling malloc() or free().
+*/
+static int patestCallback(const void*                     inputBuffer,
+                          void*                           outputBuffer,
+                          unsigned long                   framesPerBuffer,
+			              const PaStreamCallbackTimeInfo* timeInfo,
+			              PaStreamCallbackFlags           statusFlags,
+                          void*                           userData)
+{
+    int finished;
+    int i;
+    int numFrames;
+    paTestData *data = (paTestData*)userData;
+    float *out = (float*)outputBuffer;
+    (void) inputBuffer; /* Prevent "unused variable" warnings. */
+
+    /* Are we almost at end. */
+    if( data->sampsToGo < framesPerBuffer )
+    {
+        numFrames = data->sampsToGo;
+        finished = 1;
+    }
+    else
+    {
+        numFrames = framesPerBuffer;
+        finished = 0;
+    }
+    for( i=0; i<numFrames; i++ )
+    {
+        *out++ = GeneratePinkNoise( &data->leftPink );
+        *out++ = GeneratePinkNoise( &data->rightPink );
+    }
+    data->sampsToGo -= numFrames;
+    return finished;
+}
+
+/*******************************************************************/
+int main(void);
+int main(void)
+{
+    PaStream*           stream;
+    PaError             err;
+    paTestData          data;
+    PaStreamParameters  outputParameters;
+    int                 totalSamps;
+    static const double SR  = 44100.0;
+    static const int    FPB = 2048; /* Frames per buffer: 46 ms buffers. */
+    
+    /* Initialize two pink noise signals with different numbers of rows. */
+    InitializePinkNoise( &data.leftPink,  12 );
+    InitializePinkNoise( &data.rightPink, 16 );
+
+    /* Look at a few values. */
+    {
+        int i;
+        float pink;
+        for( i=0; i<20; i++ )
+        {
+            pink = GeneratePinkNoise( &data.leftPink );
+            printf("Pink = %f\n", pink );
+        }
+    }
+
+    data.sampsToGo = totalSamps = (int)(60.0 * SR);   /* Play a whole minute. */
+    err = Pa_Initialize();
+    if( err != paNoError ) goto error;
+
+    /* Open a stereo PortAudio stream so we can hear the result. */
+    outputParameters.device = Pa_GetDefaultOutputDevice(); /* Take the default output device. */
+    if (outputParameters.device == paNoDevice) {
+      fprintf(stderr,"Error: No default output device.\n");
+      goto error;
+    }
+    outputParameters.channelCount = 2;                     /* Stereo output, most likely supported. */
+    outputParameters.hostApiSpecificStreamInfo = NULL;
+    outputParameters.sampleFormat = paFloat32;             /* 32 bit floating point output. */
+    outputParameters.suggestedLatency =
+                     Pa_GetDeviceInfo(outputParameters.device)->defaultLowOutputLatency;
+    err = Pa_OpenStream(&stream,
+                        NULL,                              /* No input. */
+                        &outputParameters,
+                        SR,                                /* Sample rate. */
+                        FPB,                               /* Frames per buffer. */
+                        paClipOff, /* we won't output out of range samples so don't bother clipping them */
+                        patestCallback,
+                        &data);
+    if( err != paNoError ) goto error;
+
+    err = Pa_StartStream( stream );
+    if( err != paNoError ) goto error;
+
+    printf("Stereo pink noise for one minute...\n");
+
+    while( ( err = Pa_IsStreamActive( stream ) ) == 1 ) Pa_Sleep(100);
+    if( err < 0 ) goto error;
+
+    err = Pa_CloseStream( stream );
+    if( err != paNoError ) goto error;
+#ifdef PINK_MEASURE
+    printf("Pink min = %f, max = %f\n", pinkMin, pinkMax );
+#endif
+    Pa_Terminate();
+    return 0;
+error:
+    Pa_Terminate();
+    fprintf( stderr, "An error occured while using the portaudio stream\n" );
+    fprintf( stderr, "Error number: %d\n", err );
+    fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
+    return 0;
+}
+#endif /* PINK_TEST */