QuickTime 3 Reference
Setting up an Effect Description

The first step is to provide an effect description. The code shown in Listing 20-7 is very similar to the code described in "Creating an Effect Description" .
Listing 7 Providing an effect description


 
{

    QTAtomContainermyEffectDesc = NULL;

    OSType          myType;

    OSErr           myErr = noErr;

    long            myLong;



    // Create a new, empty effect description

    myErr = QTNewAtomContainer(&myEffectDesc);



    // This example is an effect description for a SMPTE effect

    myType = OSTypeConst(`smpt');

    myErr = QTInsertChild(myEffectDesc,

                    kParentAtomIsContainer,

                    kParameterWhatName,

                    kParameterWhatID,

                    0,

                    sizeof(myType),

                    &myType,

                    NULL);



    // Now reference the two sources to be used. These will not be items in an input map.

    // Instead the source names used will be resolved in the decompression sequence.

    myType = OSTypeConst(`srcA');

    myErr = QTInsertChild(myEffectDesc,

                    kParentAtomIsContainer,

                    kEffectSourceName,

                    1,

                    0,

                    sizeof(myType),

                    &myType,

                    NULL);



    // Add the second source

    myType = OSTypeConst(`srcB');

    myErr = QTInsertChild(myEffectDesc,

                    kParentAtomIsContainer,

                    kEffectSourceName,

                    2,

                    0,

                    sizeof(myType),

                    &myType,

                    NULL);



    // This example uses SMTPE effect number 74, so add a WipeID parameter with the value 74

    myLong = 74;

    myErr = QTInsertChild(myEffectDesc,

                    kParentAtomIsContainer,

                    OSTypeConst(`wpID'),

                    1,

                    0,

                    sizeof(myLong),

                    &myLong,

                    NULL);

}