diff options
Diffstat (limited to 'pd/portaudio_v18/pa_tests/patest_dither.c')
| -rw-r--r-- | pd/portaudio_v18/pa_tests/patest_dither.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/pd/portaudio_v18/pa_tests/patest_dither.c b/pd/portaudio_v18/pa_tests/patest_dither.c new file mode 100644 index 00000000..c58b9cea --- /dev/null +++ b/pd/portaudio_v18/pa_tests/patest_dither.c @@ -0,0 +1,152 @@ +/* + * $Id: patest_dither.c,v 1.2 2002/03/21 00:58:45 philburk Exp $ + * patest_dither.c + * Attempt to hear difference between dithered and non-dithered signal. + * This only has an effect if the native format is 16 bit. + * + * Author: Phil Burk http://www.softsynth.com + * + * 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. + * + * 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. + * + * 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. + * + */ +#include <stdio.h> +#include <math.h> +#include "portaudio.h" +#define NUM_SECONDS (4) +#define SAMPLE_RATE (44100) +#ifndef M_PI +#define M_PI (3.14159265) +#endif +#define TABLE_SIZE (200) +typedef struct paTestData +{ + float sine[TABLE_SIZE]; + float amplitude; + int left_phase; + int right_phase; +} +paTestData; +PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude ); +static int sineCallback( void *inputBuffer, void *outputBuffer, + unsigned long framesPerBuffer, + PaTimestamp outTime, void *userData ); +/* 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 sineCallback( void *inputBuffer, void *outputBuffer, + unsigned long framesPerBuffer, + PaTimestamp outTime, void *userData ) +{ + paTestData *data = (paTestData*)userData; + float *out = (float*)outputBuffer; + float amplitude = data->amplitude; + unsigned int i; + (void) outTime; + (void) inputBuffer; + for( i=0; i<framesPerBuffer; i++ ) + { + *out++ = amplitude * data->sine[data->left_phase]; /* left */ + *out++ = amplitude * data->sine[data->right_phase]; /* right */ + data->left_phase += 1; + if( data->left_phase >= TABLE_SIZE ) data->left_phase -= TABLE_SIZE; + data->right_phase += 3; /* higher pitch so we can distinguish left and right. */ + if( data->right_phase >= TABLE_SIZE ) data->right_phase -= TABLE_SIZE; + } + return 0; +} +/*******************************************************************/ +int main(void); +int main(void) +{ + PaError err; + paTestData DATA; + int i; + float amplitude = 32.0 / (1<<15); + printf("PortAudio Test: output EXTREMELY QUIET sine wave with and without dithering.\n"); + /* initialise sinusoidal wavetable */ + for( i=0; i<TABLE_SIZE; i++ ) + { + DATA.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. ); + } + printf("\nNo treatment..\n"); fflush(stdout); + err = PlaySine( &DATA, paClipOff | paDitherOff, amplitude ); + if( err < 0 ) goto error; + printf("\nClip.\n"); + fflush(stdout); + err = PlaySine( &DATA, paDitherOff, amplitude ); + if( err < 0 ) goto error; + printf("\nClip and Dither.\n"); + fflush(stdout); + err = PlaySine( &DATA, paNoFlag, amplitude ); + if( err < 0 ) goto error; + return 0; +error: + 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 -1; +} +/*****************************************************************************/ +PaError PlaySine( paTestData *data, PaStreamFlags flags, float amplitude ) +{ + PortAudioStream *stream; + PaError err; + data->left_phase = data->right_phase = 0; + data->amplitude = amplitude; + err = Pa_Initialize(); + if( err != paNoError ) goto error; + err = Pa_OpenStream( + &stream, + paNoDevice,/* default input device */ + 0, /* no input */ + paFloat32, /* 32 bit floating point input */ + NULL, + Pa_GetDefaultOutputDeviceID(), /* default output device */ + 2, /* stereo output */ + paFloat32, /* 32 bit floating point output */ + NULL, + SAMPLE_RATE, + 1024, + 0, /* number of buffers, if zero then use default minimum */ + flags, /* we won't output out of range samples so don't bother clipping them */ + sineCallback, + (void *)data ); + if( err != paNoError ) goto error; + + err = Pa_StartStream( stream ); + if( err != paNoError ) goto error; + Pa_Sleep( NUM_SECONDS * 1000 ); + printf("CPULoad = %8.6f\n", Pa_GetCPULoad( stream ) ); + err = Pa_CloseStream( stream ); + if( err != paNoError ) goto error; + Pa_Terminate(); + return paNoError; +error: + return err; +} |