/*

    File:       SetupDBHeader.c

    Contains:   Routine demonstrating how to set up the DoubleBufferHeader for SndPlayDoubleBuffer.

    Written by: Mark Cookson    

    Copyright:  Copyright © 1996-1999 by Apple Computer, Inc., All Rights Reserved.

                You may incorporate this Apple sample source code into your program(s) without

                restriction. This Apple sample source code has been provided "AS IS" and the

                responsibility for its operation is yours. You are not permitted to redistribute

                this Apple sample source code as "Apple sample source code" after having made

                changes. If you're going to re-distribute the source, we require that you make

                it clear in the source that the code was descended from Apple sample source

                code, but that you've made changes.

    Change History (most recent first):

                8/31/1999   Karl Groethe    Updated for Metrowerks Codewarror Pro 2.1

*/

#include "MyAIFF.h"

#include "SetupDBHeader.h"

#include <Sound.h>

/*  Purpose:        This sets up the fields of the SndDoubleBufferHeader

                    structure.

                    This sets the value of the compFactor variable so that

                    you can tell if the sound is compressed, and if so by

                    how much (this is used for proper buffer sizing).

    Side Effects:   None.

*/

/*-----------------------------------------------------------------------*/

OSErr   SetupDBHeader   (SoundInfoPtr theSoundInfo,

                        Fixed sampleRate,

                        short sampleSize,

                        short numChannels,

                        short compressionID,

                        long compressionType)

/*-----------------------------------------------------------------------*/

{

    CompressionInfo         compInfo;

    OSErr                   err                 = noErr;

    err = GetCompressionInfo(compressionID, compressionType, numChannels, sampleSize, &compInfo);

    theSoundInfo->doubleHeader.dbhNumChannels       = numChannels;

    theSoundInfo->doubleHeader.dbhSampleSize        = compInfo.bytesPerSample * kBitsPerByte;

    theSoundInfo->doubleHeader.dbhCompressionID     = compInfo.compressionID;

    theSoundInfo->doubleHeader.dbhPacketSize        = compInfo.bytesPerPacket;

    theSoundInfo->doubleHeader.dbhSampleRate        = sampleRate;

    theSoundInfo->doubleHeader.dbhFormat            = compInfo.format;

    theSoundInfo->bytesPerFrame                     = compInfo.bytesPerFrame;

    switch (compressionType) {

        case NoneType:

        case kOffsetBinary:

        case kTwosComplement:

            theSoundInfo->compFactor = kNoCompression;

            break;

        case kULawCompression:

        case kCDXA2Compression:

            theSoundInfo->compFactor = kCompressByTwo;

            break;

        case kMACE3Compression:

            theSoundInfo->compFactor = kCompressByThree;

            break;

        case kIMACompression:

        case kCDXA4Compression:

        case 'ADPM':

            theSoundInfo->compFactor = kCompressByFour;

            break;

        case kMACE6Compression:

            theSoundInfo->compFactor = kCompressBySix;

            break;

        default:

            DebugPrint ("\pUnknown compression type");

            theSoundInfo->compFactor = (float)compInfo.samplesPerPacket / compInfo.bytesPerPacket * compInfo.bytesPerSample + 0.5;

            break;

    }

    return err;

}