/** @file patest_leftright.c @ingroup test_src @brief Play different tone sine waves that alternate between left and right channel. The low tone should be on the left channel. @author Ross Bencina @author Phil Burk */ /* * $Id$ * * 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 #include #include "portaudio.h" #define NUM_SECONDS (8) #define SAMPLE_RATE (44100) #define FRAMES_PER_BUFFER (512) #ifndef M_PI #define M_PI (3.14159265) #endif #define TABLE_SIZE (200) #define BALANCE_DELTA (0.001) typedef struct { float sine[TABLE_SIZE]; int left_phase; int right_phase; float targetBalance; // 0.0 = left, 1.0 = right float currentBalance; } 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 ) { paTestData *data = (paTestData*)userData; float *out = (float*)outputBuffer; unsigned long i; int finished = 0; /* Prevent unused variable warnings. */ (void) inputBuffer; for( i=0; icurrentBalance < data->targetBalance ) { data->currentBalance += BALANCE_DELTA; } else if( data->currentBalance > data->targetBalance ) { data->currentBalance -= BALANCE_DELTA; } // Apply left/right balance. *out++ = data->sine[data->left_phase] * (1.0f - data->currentBalance); /* left */ *out++ = data->sine[data->right_phase] * data->currentBalance; /* 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 finished; } /*******************************************************************/ int main(void); int main(void) { PaStream *stream; PaStreamParameters outputParameters; PaError err; paTestData data; int i; printf("Play different tone sine waves that alternate between left and right channel.\n"); printf("The low tone should be on the left channel.\n"); /* initialise sinusoidal wavetable */ for( i=0; idefaultLowOutputLatency; outputParameters.hostApiSpecificStreamInfo = NULL; err = Pa_OpenStream( &stream, NULL, /* No input. */ &outputParameters, /* As above. */ SAMPLE_RATE, 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("Play for several seconds.\n"); for( i=0; i<4; i++ ) { printf("Hear low sound on left side.\n"); data.targetBalance = 0.01; Pa_Sleep( 1000 ); printf("Hear high sound on right side.\n"); data.targetBalance = 0.99; Pa_Sleep( 1000 ); } err = Pa_StopStream( stream ); if( err != paNoError ) goto error; err = Pa_CloseStream( stream ); if( err != paNoError ) goto error; Pa_Terminate(); printf("Test finished.\n"); return err; error: Pa_Terminate(); fprintf( stderr, "An error occurred while using the portaudio stream\n" ); fprintf( stderr, "Error number: %d\n", err ); fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) ); return err; }