OpenAL: Jak stworzyć prosty program "Echo mikrofonu"?

Question

Więc zastanawiam się, co byłoby najkrótszym (jeśli chodzi o efektywne linie) otwartym kodem AL do odczytu danych z domyślnego mikrofonu i wyjściem do domyślnych głośników?

Zajmuję się na Windows 7 pod Visual Studio 2008

Answer 1

Starożytny pytanie, ale tutaj jest odpowiedź. To może z pewnością być przycięte jakbyśmy naprawdę będzie dla zwięzłości, ale jest to trochę mniej niż 100 efektywnych linii:

#include <AL/al.h> // OpenAL header files 
#include <AL/alc.h> 

#include <list> 

using std::list; 

#define FREQ 22050 // Sample rate 
#define CAP_SIZE 2048 // How much to capture at a time (affects latency) 

int main(int argC,char* argV[]) 
{ 
    list<ALuint> bufferQueue; // A quick and dirty queue of buffer objects 

    ALenum errorCode=0; 
    ALuint helloBuffer[16], helloSource[1]; 
    ALCdevice* audioDevice = alcOpenDevice(NULL); // Request default audio device 
    errorCode = alcGetError(audioDevice); 
    ALCcontext* audioContext = alcCreateContext(audioDevice,NULL); // Create the audio context 
    alcMakeContextCurrent(audioContext); 
    errorCode = alcGetError(audioDevice); 
    // Request the default capture device with a half-second buffer 
    ALCdevice* inputDevice = alcCaptureOpenDevice(NULL,FREQ,AL_FORMAT_MONO16,FREQ/2); 
    errorCode = alcGetError(inputDevice); 
    alcCaptureStart(inputDevice); // Begin capturing 
    errorCode = alcGetError(inputDevice); 

    alGenBuffers(16,&helloBuffer[0]); // Create some buffer-objects 
    errorCode = alGetError(); 

    // Queue our buffers onto an STL list 
    for (int ii=0;ii<16;++ii) { 
     bufferQueue.push_back(helloBuffer[ii]); 
    } 

    alGenSources (1, &helloSource[0]); // Create a sound source 
    errorCode = alGetError(); 

    short buffer[FREQ*2]; // A buffer to hold captured audio 
    ALCint samplesIn=0; // How many samples are captured 
    ALint availBuffers=0; // Buffers to be recovered 
    ALuint myBuff; // The buffer we're using 
    ALuint buffHolder[16]; // An array to hold catch the unqueued buffers 
    bool done = false; 
    while (!done) { // Main loop 
     // Poll for recoverable buffers 
     alGetSourcei(helloSource[0],AL_BUFFERS_PROCESSED,&availBuffers); 
     if (availBuffers>0) { 
      alSourceUnqueueBuffers(helloSource[0],availBuffers,buffHolder); 
      for (int ii=0;ii<availBuffers;++ii) { 
       // Push the recovered buffers back on the queue 
       bufferQueue.push_back(buffHolder[ii]); 
      } 
     } 
     // Poll for captured audio 
     alcGetIntegerv(inputDevice,ALC_CAPTURE_SAMPLES,1,&samplesIn); 
     if (samplesIn>CAP_SIZE) { 
      // Grab the sound 
      alcCaptureSamples(inputDevice,buffer,CAP_SIZE); 

      //***** Process/filter captured data here *****// 
      //for (int ii=0;ii<CAP_SIZE;++ii) { 
      // buffer[ii]*=0.1; // Make it quieter 
      //} 

      // Stuff the captured data in a buffer-object 
      if (!bufferQueue.empty()) { // We just drop the data if no buffers are available 
       myBuff = bufferQueue.front(); bufferQueue.pop_front(); 
       alBufferData(myBuff,AL_FORMAT_MONO16,buffer,CAP_SIZE*sizeof(short),FREQ); 

       // Queue the buffer 
       alSourceQueueBuffers(helloSource[0],1,&myBuff); 

       // Restart the source if needed 
       // (if we take too long and the queue dries up, 
       // the source stops playing). 
       ALint sState=0; 
       alGetSourcei(helloSource[0],AL_SOURCE_STATE,&sState); 
       if (sState!=AL_PLAYING) { 
        alSourcePlay(helloSource[0]); 
       } 
      } 
     } 
    } 
    // Stop capture 
    alcCaptureStop(inputDevice); 
    alcCaptureCloseDevice(inputDevice); 

    // Stop the sources 
    alSourceStopv(1,&helloSource[0]); 
    for (int ii=0;ii<1;++ii) { 
     alSourcei(helloSource[ii],AL_BUFFER,0); 
    } 
    // Clean-up 
    alDeleteSources(1,&helloSource[0]); 
    alDeleteBuffers(16,&helloBuffer[0]); 
    errorCode = alGetError(); 
    alcMakeContextCurrent(NULL); 
    errorCode = alGetError(); 
    alcDestroyContext(audioContext); 
    alcCloseDevice(audioDevice); 

    return 0; 
}