QuickTime 4 Reference

Starting Video Output

Listing 5 shows how your video output component can start video output.

Listing 5 Starting video output



 
pascal ComponentResult MyQTVideoOutputBegin (Globals storage)

{

    ComponentResult err;

    long mode;



    // call the default implementation

    err = QTVideoOutputBegin (storage->baseVideoOutput);

    if (err) goto bail;



    // get the selected mode

    err = QTVideoOutputGetDisplayMode (storage->self, &mode);

    if (err) goto bail;



    // switch the hardware to the selected mode



    // remember that we now own the hardware

    storage->ownHardware = true;



bail:

    if ((err != noErr) && (storage->ownHardware == true))

        QTVideoOutputEnd (storage-> baseVideoOutput);

    return err;

}

The default implementation of the QTVideoOutputBegin function ensures that the hardware is not currently in use by other software. It also ensures that a valid display mode has been set with either the QTVideoOutputSetDisplayMode function or the QTVideoRestoreSettings function.