cannam@89: /*
cannam@89:  * $Id: $
cannam@89:  * Portable Audio I/O Library
cannam@89:  * Windows MME low level buffer user guided parameters search
cannam@89:  *
cannam@89:  * Copyright (c) 2010 Ross Bencina
cannam@89:  *
cannam@89:  * Permission is hereby granted, free of charge, to any person obtaining
cannam@89:  * a copy of this software and associated documentation files
cannam@89:  * (the "Software"), to deal in the Software without restriction,
cannam@89:  * including without limitation the rights to use, copy, modify, merge,
cannam@89:  * publish, distribute, sublicense, and/or sell copies of the Software,
cannam@89:  * and to permit persons to whom the Software is furnished to do so,
cannam@89:  * subject to the following conditions:
cannam@89:  *
cannam@89:  * The above copyright notice and this permission notice shall be
cannam@89:  * included in all copies or substantial portions of the Software.
cannam@89:  *
cannam@89:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
cannam@89:  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
cannam@89:  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
cannam@89:  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
cannam@89:  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
cannam@89:  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
cannam@89:  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
cannam@89:  */
cannam@89: 
cannam@89: /*
cannam@89:  * The text above constitutes the entire PortAudio license; however, 
cannam@89:  * the PortAudio community also makes the following non-binding requests:
cannam@89:  *
cannam@89:  * Any person wishing to distribute modifications to the Software is
cannam@89:  * requested to send the modifications to the original developer so that
cannam@89:  * they can be incorporated into the canonical version. It is also 
cannam@89:  * requested that these non-binding requests be included along with the 
cannam@89:  * license above.
cannam@89:  */
cannam@89: 
cannam@89: #include <stdio.h>
cannam@89: #include <time.h>
cannam@89: #include <math.h>
cannam@89: 
cannam@89: #define  _WIN32_WINNT 0x0501 /* for GetNativeSystemInfo */ 
cannam@89: #include <windows.h>    /* required when using pa_win_wmme.h */
cannam@89: #include <mmsystem.h>   /* required when using pa_win_wmme.h */
cannam@89: 
cannam@89: #include <conio.h>      /* for _getch */
cannam@89: 
cannam@89: 
cannam@89: #include "portaudio.h"
cannam@89: #include "pa_win_wmme.h"
cannam@89: 
cannam@89: 
cannam@89: #define DEFAULT_SAMPLE_RATE             (44100.)
cannam@89: 
cannam@89: #ifndef M_PI
cannam@89: #define M_PI  (3.14159265)
cannam@89: #endif
cannam@89: 
cannam@89: #define TABLE_SIZE              (2048)
cannam@89: 
cannam@89: #define CHANNEL_COUNT           (2)
cannam@89: 
cannam@89: 
cannam@89: /* seach parameters. we test all buffer counts in this range */
cannam@89: #define MIN_WMME_BUFFER_COUNT        (2)
cannam@89: #define MAX_WMME_BUFFER_COUNT        (12)
cannam@89: 
cannam@89: 
cannam@89: /*******************************************************************/
cannam@89: /* functions to query and print Windows version information */
cannam@89: 
cannam@89: typedef BOOL (WINAPI *LPFN_ISWOW64PROCESS) (HANDLE, PBOOL);
cannam@89: 
cannam@89: LPFN_ISWOW64PROCESS fnIsWow64Process;
cannam@89: 
cannam@89: static BOOL IsWow64()
cannam@89: {
cannam@89:     BOOL bIsWow64 = FALSE;
cannam@89: 
cannam@89:     //IsWow64Process is not available on all supported versions of Windows.
cannam@89:     //Use GetModuleHandle to get a handle to the DLL that contains the function
cannam@89:     //and GetProcAddress to get a pointer to the function if available.
cannam@89: 
cannam@89:     fnIsWow64Process = (LPFN_ISWOW64PROCESS) GetProcAddress(
cannam@89:         GetModuleHandle(TEXT("kernel32")),"IsWow64Process" );
cannam@89: 
cannam@89:     if(NULL != fnIsWow64Process)
cannam@89:     {
cannam@89:         if (!fnIsWow64Process(GetCurrentProcess(),&bIsWow64))
cannam@89:         {
cannam@89:             //handle error
cannam@89:         }
cannam@89:     }
cannam@89:     return bIsWow64;
cannam@89: }
cannam@89: 
cannam@89: static void printWindowsVersionInfo( FILE *fp )
cannam@89: {
cannam@89:     OSVERSIONINFOEX osVersionInfoEx;
cannam@89:     SYSTEM_INFO systemInfo;
cannam@89:     const char *osName = "Unknown";
cannam@89:     const char *osProductType = "";
cannam@89:     const char *processorArchitecture = "Unknown";
cannam@89: 
cannam@89:     memset( &osVersionInfoEx, 0, sizeof(OSVERSIONINFOEX) );
cannam@89:     osVersionInfoEx.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
cannam@89:     GetVersionEx( &osVersionInfoEx );
cannam@89: 
cannam@89:     
cannam@89:     if( osVersionInfoEx.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS ){
cannam@89:         switch( osVersionInfoEx.dwMinorVersion ){
cannam@89:             case 0: osName = "Windows 95"; break;
cannam@89:             case 10: osName = "Windows 98"; break;  // could also be 98SE (I've seen code discriminate based 
cannam@89:                                                     // on osInfo.Version.Revision.ToString() == "2222A")
cannam@89:             case 90: osName = "Windows Me"; break;
cannam@89:         }
cannam@89:     }else if( osVersionInfoEx.dwPlatformId == VER_PLATFORM_WIN32_NT ){
cannam@89:         switch( osVersionInfoEx.dwMajorVersion ){
cannam@89:             case 3: osName = "Windows NT 3.51"; break;
cannam@89:             case 4: osName = "Windows NT 4.0"; break;
cannam@89:             case 5: switch( osVersionInfoEx.dwMinorVersion ){
cannam@89:                         case 0: osName = "Windows 2000"; break;
cannam@89:                         case 1: osName = "Windows XP"; break;
cannam@89:                         case 2:
cannam@89:                             if( osVersionInfoEx.wSuiteMask & 0x00008000 /*VER_SUITE_WH_SERVER*/ ){
cannam@89:                                 osName = "Windows Home Server";
cannam@89:                             }else{
cannam@89:                                 if( osVersionInfoEx.wProductType == VER_NT_WORKSTATION ){
cannam@89:                                     osName = "Windows XP Professional x64 Edition (?)";
cannam@89:                                 }else{
cannam@89:                                     if( GetSystemMetrics(/*SM_SERVERR2*/89) == 0 )
cannam@89:                                         osName = "Windows Server 2003";
cannam@89:                                     else
cannam@89:                                         osName = "Windows Server 2003 R2";
cannam@89:                                 }
cannam@89:                             }break;
cannam@89:                     }break;
cannam@89:             case 6:switch( osVersionInfoEx.dwMinorVersion ){
cannam@89:                         case 0: 
cannam@89:                             if( osVersionInfoEx.wProductType == VER_NT_WORKSTATION )
cannam@89:                                 osName = "Windows Vista";
cannam@89:                             else
cannam@89:                                 osName = "Windows Server 2008";
cannam@89:                             break;
cannam@89:                         case 1: 
cannam@89:                             if( osVersionInfoEx.wProductType == VER_NT_WORKSTATION )
cannam@89:                                 osName = "Windows 7";
cannam@89:                             else
cannam@89:                                 osName = "Windows Server 2008 R2";
cannam@89:                             break;
cannam@89:                     }break;
cannam@89:         }
cannam@89:     }
cannam@89: 
cannam@89:     if(osVersionInfoEx.dwMajorVersion == 4)
cannam@89:     {
cannam@89:         if(osVersionInfoEx.wProductType == VER_NT_WORKSTATION)
cannam@89:             osProductType = "Workstation";
cannam@89:         else if(osVersionInfoEx.wProductType == VER_NT_SERVER)
cannam@89:             osProductType = "Server";
cannam@89:     }
cannam@89:     else if(osVersionInfoEx.dwMajorVersion == 5)
cannam@89:     {
cannam@89:         if(osVersionInfoEx.wProductType == VER_NT_WORKSTATION)
cannam@89:         {
cannam@89:             if((osVersionInfoEx.wSuiteMask & VER_SUITE_PERSONAL) == VER_SUITE_PERSONAL)
cannam@89:                 osProductType = "Home Edition"; // Windows XP Home Edition
cannam@89:             else
cannam@89:                 osProductType = "Professional"; // Windows XP / Windows 2000 Professional
cannam@89:         }
cannam@89:         else if(osVersionInfoEx.wProductType == VER_NT_SERVER)
cannam@89:         {
cannam@89:             if(osVersionInfoEx.dwMinorVersion == 0) 
cannam@89:             {
cannam@89:                 if((osVersionInfoEx.wSuiteMask & VER_SUITE_DATACENTER) == VER_SUITE_DATACENTER)
cannam@89:                     osProductType = "Datacenter Server"; // Windows 2000 Datacenter Server
cannam@89:                 else if((osVersionInfoEx.wSuiteMask & VER_SUITE_ENTERPRISE) == VER_SUITE_ENTERPRISE)
cannam@89:                     osProductType = "Advanced Server"; // Windows 2000 Advanced Server
cannam@89:                 else
cannam@89:                     osProductType = "Server"; // Windows 2000 Server
cannam@89:             }
cannam@89:         }
cannam@89:         else
cannam@89:         {
cannam@89:             if((osVersionInfoEx.wSuiteMask & VER_SUITE_DATACENTER) == VER_SUITE_DATACENTER)
cannam@89:                 osProductType = "Datacenter Edition"; // Windows Server 2003 Datacenter Edition
cannam@89:             else if((osVersionInfoEx.wSuiteMask & VER_SUITE_ENTERPRISE) == VER_SUITE_ENTERPRISE)
cannam@89:                 osProductType = "Enterprise Edition"; // Windows Server 2003 Enterprise Edition
cannam@89:             else if((osVersionInfoEx.wSuiteMask & VER_SUITE_BLADE) == VER_SUITE_BLADE)
cannam@89:                 osProductType = "Web Edition"; // Windows Server 2003 Web Edition
cannam@89:             else
cannam@89:                 osProductType = "Standard Edition"; // Windows Server 2003 Standard Edition
cannam@89:         }
cannam@89:     }
cannam@89: 
cannam@89:     memset( &systemInfo, 0, sizeof(SYSTEM_INFO) );
cannam@89:     GetNativeSystemInfo( &systemInfo );
cannam@89: 
cannam@89:     if( systemInfo.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_INTEL )
cannam@89:         processorArchitecture = "x86";
cannam@89:     else if( systemInfo.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64 )
cannam@89:         processorArchitecture = "x64";
cannam@89:     else if( systemInfo.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_IA64 )
cannam@89:         processorArchitecture = "Itanium";
cannam@89: 
cannam@89: 
cannam@89:     fprintf( fp, "OS name and edition: %s %s\n", osName, osProductType );
cannam@89:     fprintf( fp, "OS version: %d.%d.%d %S\n", 
cannam@89:                 osVersionInfoEx.dwMajorVersion, osVersionInfoEx.dwMinorVersion, 
cannam@89:                 osVersionInfoEx.dwBuildNumber, osVersionInfoEx.szCSDVersion );
cannam@89:     fprintf( fp, "Processor architecture: %s\n", processorArchitecture );
cannam@89:     fprintf( fp, "WoW64 process: %s\n", IsWow64() ? "Yes" : "No" );
cannam@89: }
cannam@89: 
cannam@89: static void printTimeAndDate( FILE *fp )
cannam@89: {
cannam@89:     struct tm *local;
cannam@89:     time_t t;
cannam@89: 
cannam@89:     t = time(NULL);
cannam@89:     local = localtime(&t);
cannam@89:     fprintf(fp, "Local time and date: %s", asctime(local));
cannam@89:     local = gmtime(&t);
cannam@89:     fprintf(fp, "UTC time and date: %s", asctime(local));
cannam@89: }
cannam@89: 
cannam@89: /*******************************************************************/
cannam@89: 
cannam@89: typedef struct
cannam@89: {
cannam@89:     float sine[TABLE_SIZE];
cannam@89: 	double phase;
cannam@89:     double phaseIncrement;
cannam@89:     volatile int fadeIn;
cannam@89:     volatile int fadeOut;
cannam@89:     double amp;
cannam@89: }
cannam@89: paTestData;
cannam@89: 
cannam@89: static paTestData data;
cannam@89: 
cannam@89: /* This routine will be called by the PortAudio engine when audio is needed.
cannam@89: ** It may called at interrupt level on some machines so don't do anything
cannam@89: ** that could mess up the system like calling malloc() or free().
cannam@89: */
cannam@89: static int patestCallback( const void *inputBuffer, void *outputBuffer,
cannam@89:                             unsigned long framesPerBuffer,
cannam@89:                             const PaStreamCallbackTimeInfo* timeInfo,
cannam@89:                             PaStreamCallbackFlags statusFlags,
cannam@89:                             void *userData )
cannam@89: {
cannam@89:     paTestData *data = (paTestData*)userData;
cannam@89:     float *out = (float*)outputBuffer;
cannam@89:     unsigned long i,j;
cannam@89: 
cannam@89:     (void) timeInfo; /* Prevent unused variable warnings. */
cannam@89:     (void) statusFlags;
cannam@89:     (void) inputBuffer;
cannam@89:     
cannam@89:     for( i=0; i<framesPerBuffer; i++ )
cannam@89:     {
cannam@89:         float x = data->sine[(int)data->phase];
cannam@89:         data->phase += data->phaseIncrement;
cannam@89:         if( data->phase >= TABLE_SIZE ){
cannam@89: 			data->phase -= TABLE_SIZE;
cannam@89: 		}
cannam@89: 
cannam@89:         x *= data->amp;
cannam@89:         if( data->fadeIn ){
cannam@89:             data->amp += .001;
cannam@89:             if( data->amp >= 1. )
cannam@89:                 data->fadeIn = 0;
cannam@89:         }else if( data->fadeOut ){
cannam@89:             if( data->amp > 0 )
cannam@89:                 data->amp -= .001;
cannam@89:         }
cannam@89: 
cannam@89: 		for( j = 0; j < CHANNEL_COUNT; ++j ){
cannam@89:             *out++ = x;
cannam@89: 		}
cannam@89: 	}
cannam@89:     
cannam@89:     if( data->amp > 0 )
cannam@89:         return paContinue;
cannam@89:     else
cannam@89:         return paComplete;
cannam@89: }
cannam@89: 
cannam@89: 
cannam@89: #define YES     1
cannam@89: #define NO      0
cannam@89: 
cannam@89: 
cannam@89: static int playUntilKeyPress( int deviceIndex, float sampleRate, 
cannam@89:                              int framesPerUserBuffer, int framesPerWmmeBuffer, int wmmeBufferCount )
cannam@89: {
cannam@89:     PaStreamParameters outputParameters;
cannam@89:     PaWinMmeStreamInfo wmmeStreamInfo;
cannam@89:     PaStream *stream;
cannam@89:     PaError err;
cannam@89:     int c;
cannam@89: 
cannam@89:     outputParameters.device = deviceIndex;
cannam@89:     outputParameters.channelCount = CHANNEL_COUNT;
cannam@89:     outputParameters.sampleFormat = paFloat32; /* 32 bit floating point processing */
cannam@89:     outputParameters.suggestedLatency = 0; /*Pa_GetDeviceInfo( outputParameters.device )->defaultLowOutputLatency;*/
cannam@89:     outputParameters.hostApiSpecificStreamInfo = NULL;
cannam@89: 
cannam@89:     wmmeStreamInfo.size = sizeof(PaWinMmeStreamInfo);
cannam@89:     wmmeStreamInfo.hostApiType = paMME; 
cannam@89:     wmmeStreamInfo.version = 1;
cannam@89:     wmmeStreamInfo.flags = paWinMmeUseLowLevelLatencyParameters | paWinMmeDontThrottleOverloadedProcessingThread;
cannam@89:     wmmeStreamInfo.framesPerBuffer = framesPerWmmeBuffer;
cannam@89:     wmmeStreamInfo.bufferCount = wmmeBufferCount;
cannam@89:     outputParameters.hostApiSpecificStreamInfo = &wmmeStreamInfo;
cannam@89: 
cannam@89:     err = Pa_OpenStream(
cannam@89:               &stream,
cannam@89:               NULL, /* no input */
cannam@89:               &outputParameters,
cannam@89:               sampleRate,
cannam@89:               framesPerUserBuffer,
cannam@89:               paClipOff | paPrimeOutputBuffersUsingStreamCallback,      /* we won't output out of range samples so don't bother clipping them */
cannam@89:               patestCallback,
cannam@89:               &data );
cannam@89:     if( err != paNoError ) goto error;
cannam@89: 
cannam@89:     data.amp = 0;
cannam@89:     data.fadeIn = 1;
cannam@89:     data.fadeOut = 0;
cannam@89:     data.phase = 0;
cannam@89:     data.phaseIncrement = 15 + ((rand()%100) / 10); // randomise pitch
cannam@89: 
cannam@89:     err = Pa_StartStream( stream );
cannam@89:     if( err != paNoError ) goto error;
cannam@89: 
cannam@89: 
cannam@89:     do{
cannam@89:         printf( "Trying buffer size %d.\nIf it sounds smooth (without clicks or glitches) press 'y', if it sounds bad press 'n' ('q' to quit)\n", framesPerWmmeBuffer );
cannam@89:         c = tolower(_getch());
cannam@89:         if( c == 'q' ){
cannam@89:             Pa_Terminate();
cannam@89:             exit(0);
cannam@89:         }
cannam@89:     }while( c != 'y' && c != 'n' );
cannam@89: 
cannam@89:     data.fadeOut = 1;
cannam@89:     while( Pa_IsStreamActive(stream) == 1 )
cannam@89:         Pa_Sleep( 100 );
cannam@89: 
cannam@89:     err = Pa_StopStream( stream );
cannam@89:     if( err != paNoError ) goto error;
cannam@89: 
cannam@89:     err = Pa_CloseStream( stream );
cannam@89:     if( err != paNoError ) goto error;
cannam@89: 
cannam@89:     return (c == 'y') ? YES : NO;
cannam@89: 
cannam@89: error:
cannam@89:     return err;
cannam@89: }
cannam@89: 
cannam@89: /*******************************************************************/
cannam@89: static void usage( int wmmeHostApiIndex )
cannam@89: {
cannam@89:     int i;
cannam@89: 
cannam@89:     fprintf( stderr, "PortAudio WMME output latency user guided test\n" );
cannam@89:     fprintf( stderr, "Usage: x.exe mme-device-index [sampleRate [min-buffer-count max-buffer-count]]\n" );
cannam@89:     fprintf( stderr, "Invalid device index. Use one of these:\n" );
cannam@89:     for( i=0; i < Pa_GetDeviceCount(); ++i ){
cannam@89: 
cannam@89:         if( Pa_GetDeviceInfo(i)->hostApi == wmmeHostApiIndex && Pa_GetDeviceInfo(i)->maxOutputChannels > 0  )
cannam@89:             fprintf( stderr, "%d (%s)\n", i, Pa_GetDeviceInfo(i)->name );
cannam@89:     }
cannam@89:     Pa_Terminate();
cannam@89:     exit(-1);
cannam@89: }
cannam@89: 
cannam@89: /*
cannam@89:     ideas: 
cannam@89:         o- could be testing with 80% CPU load
cannam@89:         o- could test with different channel counts
cannam@89: */
cannam@89: 
cannam@89: int main(int argc, char* argv[])
cannam@89: {
cannam@89:     PaError err;
cannam@89:     int i;
cannam@89:     int deviceIndex;
cannam@89:     int wmmeBufferCount, wmmeBufferSize, smallestWorkingBufferSize;
cannam@89:     int smallestWorkingBufferingLatencyFrames;
cannam@89:     int min, max, mid;
cannam@89:     int testResult;
cannam@89:     FILE *resultsFp;
cannam@89:     int wmmeHostApiIndex;
cannam@89:     const PaHostApiInfo *wmmeHostApiInfo;
cannam@89:     double sampleRate = DEFAULT_SAMPLE_RATE;
cannam@89:     int wmmeMinBufferCount = MIN_WMME_BUFFER_COUNT;
cannam@89:     int wmmeMaxBufferCount = MAX_WMME_BUFFER_COUNT;
cannam@89: 
cannam@89:     err = Pa_Initialize();
cannam@89:     if( err != paNoError ) goto error;
cannam@89: 
cannam@89:     wmmeHostApiIndex = Pa_HostApiTypeIdToHostApiIndex( paMME );
cannam@89:     wmmeHostApiInfo = Pa_GetHostApiInfo( wmmeHostApiIndex );
cannam@89: 
cannam@89:     if( argc > 5 )
cannam@89:         usage(wmmeHostApiIndex);
cannam@89: 
cannam@89: 	deviceIndex = wmmeHostApiInfo->defaultOutputDevice;
cannam@89: 	if( argc >= 2 ){
cannam@89:         deviceIndex = -1;
cannam@89: 		if( sscanf( argv[1], "%d", &deviceIndex ) != 1 )
cannam@89:             usage(wmmeHostApiIndex);
cannam@89:         if( deviceIndex < 0 || deviceIndex >= Pa_GetDeviceCount() || Pa_GetDeviceInfo(deviceIndex)->hostApi != wmmeHostApiIndex ){
cannam@89:             usage(wmmeHostApiIndex);
cannam@89:         }
cannam@89: 	}
cannam@89: 
cannam@89:     printf( "Using device id %d (%s)\n", deviceIndex, Pa_GetDeviceInfo(deviceIndex)->name );
cannam@89: 
cannam@89:     if( argc >= 3 ){
cannam@89:         if( sscanf( argv[2], "%lf", &sampleRate ) != 1 )
cannam@89:             usage(wmmeHostApiIndex);
cannam@89:     }
cannam@89: 
cannam@89:     printf( "Testing with sample rate %f.\n", (float)sampleRate );
cannam@89: 
cannam@89:     if( argc == 4 ){
cannam@89:         if( sscanf( argv[3], "%d", &wmmeMinBufferCount ) != 1 )
cannam@89:             usage(wmmeHostApiIndex);
cannam@89:         wmmeMaxBufferCount = wmmeMinBufferCount;
cannam@89:     }
cannam@89: 
cannam@89:     if( argc == 5 ){
cannam@89:         if( sscanf( argv[3], "%d", &wmmeMinBufferCount ) != 1 )
cannam@89:             usage(wmmeHostApiIndex);
cannam@89:         if( sscanf( argv[4], "%d", &wmmeMaxBufferCount ) != 1 )
cannam@89:             usage(wmmeHostApiIndex);
cannam@89:     }
cannam@89: 
cannam@89:     printf( "Testing buffer counts from %d to %d\n", wmmeMinBufferCount, wmmeMaxBufferCount );
cannam@89: 
cannam@89: 
cannam@89:     /* initialise sinusoidal wavetable */
cannam@89:     for( i=0; i<TABLE_SIZE; i++ )
cannam@89:     {
cannam@89:         data.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
cannam@89:     }
cannam@89: 
cannam@89: 	data.phase = 0;
cannam@89: 
cannam@89:     resultsFp = fopen( "results.txt", "at" );
cannam@89:     fprintf( resultsFp, "*** WMME smallest working output buffer sizes\n" );
cannam@89: 
cannam@89:     printTimeAndDate( resultsFp );
cannam@89:     printWindowsVersionInfo( resultsFp );
cannam@89:     
cannam@89:     fprintf( resultsFp, "audio device: %s\n", Pa_GetDeviceInfo( deviceIndex )->name );
cannam@89:     fflush( resultsFp );
cannam@89: 
cannam@89:     fprintf( resultsFp, "Sample rate: %f\n", (float)sampleRate );
cannam@89:     fprintf( resultsFp, "Buffer count, Smallest working buffer size (frames), Smallest working buffering latency (frames), Smallest working buffering latency (Seconds)\n" );
cannam@89: 
cannam@89:     for( wmmeBufferCount = wmmeMinBufferCount; wmmeBufferCount <= wmmeMaxBufferCount; ++wmmeBufferCount ){
cannam@89:  
cannam@89:         printf( "Test %d of %d\n", (wmmeBufferCount - wmmeMinBufferCount) + 1, (wmmeMaxBufferCount-wmmeMinBufferCount) + 1 );
cannam@89:         printf( "Testing with %d buffers...\n", wmmeBufferCount );
cannam@89: 
cannam@89:         /*
cannam@89:             Binary search after Niklaus Wirth
cannam@89:             from http://en.wikipedia.org/wiki/Binary_search_algorithm#The_algorithm
cannam@89:          */
cannam@89:         min = 1;
cannam@89:         max = (int)((sampleRate * .3) / (wmmeBufferCount-1)); //8192;    /* we assume that this size works 300ms */
cannam@89:         smallestWorkingBufferSize = 0;
cannam@89: 
cannam@89:         do{
cannam@89:             mid = min + ((max - min) / 2);
cannam@89: 
cannam@89:             wmmeBufferSize = mid;
cannam@89:             testResult = playUntilKeyPress( deviceIndex, sampleRate, wmmeBufferSize, wmmeBufferSize, wmmeBufferCount );
cannam@89: 
cannam@89:             if( testResult == YES ){
cannam@89:                 max = mid - 1;
cannam@89:                 smallestWorkingBufferSize = wmmeBufferSize;
cannam@89:             }else{
cannam@89:                 min = mid + 1;
cannam@89:             }
cannam@89:              
cannam@89:         }while( (min <= max) && (testResult == YES || testResult == NO) );
cannam@89: 
cannam@89:         smallestWorkingBufferingLatencyFrames = smallestWorkingBufferSize * (wmmeBufferCount - 1);
cannam@89: 
cannam@89:         printf( "Smallest working buffer size for %d buffers is: %d\n", wmmeBufferCount, smallestWorkingBufferSize );
cannam@89:         printf( "Corresponding to buffering latency of %d frames, or %f seconds.\n", smallestWorkingBufferingLatencyFrames, smallestWorkingBufferingLatencyFrames / sampleRate );
cannam@89: 
cannam@89:         fprintf( resultsFp, "%d, %d, %d, %f\n", wmmeBufferCount, smallestWorkingBufferSize, smallestWorkingBufferingLatencyFrames, smallestWorkingBufferingLatencyFrames / sampleRate );
cannam@89:         fflush( resultsFp );
cannam@89:     }
cannam@89: 
cannam@89:     fprintf( resultsFp, "###\n" );
cannam@89:     fclose( resultsFp );
cannam@89:     
cannam@89:     Pa_Terminate();
cannam@89:     printf("Test finished.\n");
cannam@89:     
cannam@89:     return err;
cannam@89: error:
cannam@89:     Pa_Terminate();
cannam@89:     fprintf( stderr, "An error occured while using the portaudio stream\n" );
cannam@89:     fprintf( stderr, "Error number: %d\n", err );
cannam@89:     fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
cannam@89:     return err;
cannam@89: }
cannam@89: