Download .wav file for OpenAL in Cocoa

Question

I need to upload sound files to an OpenAL Cocoa application.

Progress:

• The OpenAL utility function alutLoadWAVFile is deprecated; The alut header is no longer included in the Mac OS X SDK. According to TechNotes, the actual code still exists for binary compatibility. However, if I try to add an declaration for the function, the code will compile, but the linker will be interrupted, stating that the symbol for alutLoadWAVFile was not found. (I am contacting OpenAL.framework).

• However, the Apple OpenAL sample code still uses this symbol. When I clean up the sample code project, it compiles and links just fine. However, there is no declaration of the function that can be found. (Side question: how can this be built and connected?)

So, I found George Warner's code on Apple containing replacement functions for alutCreateBufferFromFile and alutLoadMemoryFromFile. Although it is able to create an OpenAL buffer directly from most audio files of any type, this code appears to support only 8-bit mono files. 44-kHz 16-bit stereo or monaural files cause unpleasant hissing and trimming. (Files are fine, Quicktime plays them perfectly.)

So my question is: can someone point me to some .wav Cocoa / Carbon download / help code suitable for use with the OpenAL buffer? Thankyou.

Answer 1

, , , Google, WAV. , , - .

static bool LoadWAVFile(const char* filename, ALenum* format, ALvoid** data, ALsizei* size, ALsizei* freq, Float64* estimatedDurationOut)
{
    CFStringRef filenameStr = CFStringCreateWithCString( NULL, filename, kCFStringEncodingUTF8 );
    CFURLRef url = CFURLCreateWithFileSystemPath( NULL, filenameStr, kCFURLPOSIXPathStyle, false );
    CFRelease( filenameStr );

    AudioFileID audioFile;
    OSStatus error = AudioFileOpenURL( url, kAudioFileReadPermission, kAudioFileWAVEType, &audioFile );
    CFRelease( url );

    if ( error != noErr )
    {
        fprintf( stderr, "Error opening audio file. %d\n", error );
        return false;
    }

    AudioStreamBasicDescription basicDescription;
    UInt32 propertySize = sizeof(basicDescription);
    error = AudioFileGetProperty( audioFile, kAudioFilePropertyDataFormat, &propertySize, &basicDescription );

    if ( error != noErr )
    {
        fprintf( stderr, "Error reading audio file basic description. %d\n", error );
        AudioFileClose( audioFile );
        return false;
    }

    if ( basicDescription.mFormatID != kAudioFormatLinearPCM )
    {
        // Need PCM for Open AL. WAVs are (I believe) by definition PCM, so this check isn't necessary. It just here
        // in case I ever use this with another audio format.
        fprintf( stderr, "Audio file is not linear-PCM. %d\n", basicDescription.mFormatID );
        AudioFileClose( audioFile );
        return false;
    }

    UInt64 audioDataByteCount = 0;
    propertySize = sizeof(audioDataByteCount);
    error = AudioFileGetProperty( audioFile, kAudioFilePropertyAudioDataByteCount, &propertySize, &audioDataByteCount );
    if ( error != noErr )
    {
        fprintf( stderr, "Error reading audio file byte count. %d\n", error );
        AudioFileClose( audioFile );
        return false;
    }

    Float64 estimatedDuration = 0;
    propertySize = sizeof(estimatedDuration);
    error = AudioFileGetProperty( audioFile, kAudioFilePropertyEstimatedDuration, &propertySize, &estimatedDuration );
    if ( error != noErr )
    {
        fprintf( stderr, "Error reading estimated duration of audio file. %d\n", error );
        AudioFileClose( audioFile );
        return false;
    }

    ALenum alFormat = 0;

    if ( basicDescription.mChannelsPerFrame == 1 )
    {
        if ( basicDescription.mBitsPerChannel == 8 )
            alFormat = AL_FORMAT_MONO8;
        else if ( basicDescription.mBitsPerChannel == 16 )
            alFormat = AL_FORMAT_MONO16;
        else
        {
            fprintf( stderr, "Expected 8 or 16 bits for the mono channel but got %d\n", basicDescription.mBitsPerChannel );
            AudioFileClose( audioFile );
            return false;
        }

    }
    else if ( basicDescription.mChannelsPerFrame == 2 )
    {
        if ( basicDescription.mBitsPerChannel == 8 )
            alFormat = AL_FORMAT_STEREO8;
        else if ( basicDescription.mBitsPerChannel == 16 )
            alFormat = AL_FORMAT_STEREO16;
        else
        {
            fprintf( stderr, "Expected 8 or 16 bits per channel but got %d\n", basicDescription.mBitsPerChannel );
            AudioFileClose( audioFile );
            return false;
        }
    }
    else
    {
        fprintf( stderr, "Expected 1 or 2 channels in audio file but got %d\n", basicDescription.mChannelsPerFrame );
        AudioFileClose( audioFile );
        return false;
    }

    UInt32 numBytesToRead = audioDataByteCount;
    void* buffer = malloc( numBytesToRead );

    if ( buffer == NULL )
    {
        fprintf( stderr, "Error allocating buffer for audio data of size %u\n", numBytesToRead );
        return false;
    }

    error = AudioFileReadBytes( audioFile, false, 0, &numBytesToRead, buffer );
    AudioFileClose( audioFile );

    if ( error != noErr )
    {
        fprintf( stderr, "Error reading audio bytes. %d\n", error );
        free(buffer);
        return false;
    }

    if ( numBytesToRead != audioDataByteCount )
    {
        fprintf( stderr, "Tried to read %lld bytes from the audio file but only got %d bytes\n", audioDataByteCount, numBytesToRead );
        free(buffer);
        return false;
    }

    *freq = basicDescription.mSampleRate;
    *size = audioDataByteCount;
    *format = alFormat;
    *data = buffer;
    *estimatedDurationOut = estimatedDuration;

    return true;
}

Answer 2

AudioFileReadBytes Audio Services. Finch, . Sound + IO.

Answer 3

, : http://www.openal.org/, Apple technote?

As for how the sample code connects and builds, it does not find the prototype (if you enable -Wall, you will get a warning about the implicit function), but OpenAL.framework - at least in the SDK they are using in the sample project - actually exports _alutLoadWAVFile which you can check with nm. What is the exact link error and which SDK are you using?