// Extract the 'what' atom to find out what kind of effect it is.

    // This information is returned to us by the effects dialog which

    // is invoked using the QTStandardParameterDialogDoAction function.

    // We'll use this information when we build the effects description

    // a bit further down in the code.

    {

        QTAtom          myEffectAtom;

        QTAtomID        myEffectAtomID;

        long            myEffectCodeSize;

        Ptr             myEffectCodePtr;

        myEffectAtom = QTFindChildByIndex(gEffectSample, kParentAtomIsContainer, kParameterWhatName, kParameterWhatID, &myEffectAtomID);

        myErr = QTLockContainer(gEffectSample);

        BailError(myErr);

        myErr = QTGetAtomDataPtr(gEffectSample, myEffectAtom, &myEffectCodeSize, &myEffectCodePtr);

        BailError(myErr);

        if (myEffectCodeSize != sizeof(OSType)) {

            myErr = paramErr;

            goto bail;

        }

        // get the effect code

        myEffectCode = *(OSType *)myEffectCodePtr;      // "tsk"

        myEffectCode = EndianU32_BtoN(myEffectCode);    // because the data is read from an atom container

        myErr = QTUnlockContainer(gEffectSample);

        BailError(myErr);

    }