Mac OS Sound
Converting to 32-bit Little Endian Data

A code example for converting to 32 bit little endian data is shown in Listing 5.
Listing 10 Converting to Little Endian


 
OSErr ConvertToLittleEndian(Ptr inputPtr, Ptr outputPtr)

{

    SoundConverter       sc;

    SoundComponentData   inputFormat, outputFormat;

    unsigned long        inputFrames, inputBytes;

    unsigned long        outputFrames, outputBytes;

    void                 *littleEndianAtomsList;

    OSErr                err;



    inputFormat.flags = 0;

    inputFormat.format = k16BitBigEndianFormat;

    inputFormat.numChannels = 1;

    inputFormat.sampleSize = 16;

    inputFormat.sampleRate = rate22050hz;

    inputFormat.sampleCount = 0;

    inputFormat.buffer = nil;

    inputFormat.reserved = 0;



    outputFormat.flags = 0;

    outputFormat.format = k32BitFormat;

    outputFormat.numChannels = 1;

    outputFormat.sampleSize = 16;

    outputFormat.sampleRate = rate22050hz;

    outputFormat.sampleCount = 0;

    outputFormat.buffer = nil;

    outputFormat.reserved = 0;



    err = SoundConverterOpen(&inputFormat, &outputFormat, &sc);

    if (err != noErr) return (err);



    err = SoundConverterGetBufferSizes(sc, kOurInputBytesTarget,

                            &inputFrames,&inputBytes, &outputBytes);

    if (err != noErr) return (err);



    err = CreateAudioAtomsList(k32BitFormat, true, 

                                &littleEndianAtomsList);

    if (err != noErr) return (err);



    err = SoundConverterSetInfo(sc, siCompressionParams, 

                                littleEndianAtomsList);

    if (err != noErr) return (err);



    err = SoundConverterBeginConversion(sc);

    if (err != noErr) return (err);



    err = SoundConverterConvertBuffer(sc, inputPtr, inputFrames, 

                                outputPtr,&outputFrames, &outputBytes);

    if (err != noErr) return (err);



    err = SoundConverterEndConversion(sc, outputPtr, &outputFrames, 

                                        &outputBytes);

    if (err != noErr) return (err);



    err = SoundConverterClose(sc);

    if (err != noErr) return (err);

}