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Technical Q&A QA1476

Using the kQTPropertyClass_DRM properties with QuickTime

Q: How can an application determine if some QuickTime media (such as an imported music file) is DRM-protected and if so, find out if the current machine is authorized to play it?

A: QuickTime defines a number of DRM properties in ImageCompression.h. Media Handlers may be queried to determine the value of the kQTDRMPropertyID_IsProtected and kQTDRMPropertyID_IsAuthorized properties, and may query or set the kQTDRMPropertyID_InteractWithUser property.

/* DRM properties*/

enum {

    kQTPropertyClass_DRM = 'drm '

};

enum {

    kQTDRMPropertyID_InteractWithUser = 'shui', /* Boolean* */

    kQTDRMPropertyID_IsProtected  = 'prot',     /* Boolean* */

    kQTDRMPropertyID_IsAuthorized = 'auth'      /* Boolean* */

};

Applications query a Media Handler Component for properties of the class kQTPropertyClass_DRM by calling QTGetComponentProperty and passing in a MediaHandler (an instance of the media handler component for the media the application is interested in) as the first parameter. Applications may also set the kQTDRMPropertyID_InteractWithUser property by calling QTSetComponentProperty. See Listing 1.

If the property does not exist a kQTPropertyNotSupportedErr (-2195) is returned.

Listing 1 Example use of kQTPropertyClass_DRM properties.

OSStatus CheckSoundMediaIsAuthorized(Movie inMovie,

                                     UInt32 inSoundTrackIndex,

                                     Boolean inInteractWithUser,

                                     Boolean *outIsAuthorized)

    Track aTrack;

    Media aMedia;

    MediaHandler mh;

    Boolean isProtected;

    OSStatus err = paramErr;

    // get n sound track

    aTrack = GetMovieIndTrackType(inMovie, inSoundTrackIndex, SoundMediaType,

                                  movieTrackMediaType | movieTrackEnabledOnly);

    if (aTrack) {

        // get the track media

        aMedia = GetTrackMedia(aTrack);

        if (aMedia) {

            // get the media handler we can query

            mh = GetMediaHandler(aMedia);

            if (mh) {

                // is this media protected?

                err = QTGetComponentProperty(mh, kQTPropertyClass_DRM, kQTDRMPropertyID_IsProtected,

                                             sizeof(isProtected), &isProtected, NULL);

                if ((noErr == err) && isProtected) {

                    // if so, is this media authorized on this machine?

                    // user interaction may be turned off so no automatic dialog will pop up

                    // if the machine is not authorized -- an application may therefore choose

                    // to show their own custom UI and direct the user appropriately

                    QTSetComponentProperty(mh, kQTPropertyClass_DRM, kQTDRMPropertyID_InteractWithUser,

                                           sizeof(inInteractWithUser), &inInteractWithUser);

                    err = QTGetComponentProperty(mh, kQTPropertyClass_DRM, kQTDRMPropertyID_IsAuthorized,

                                                 sizeof(*outIsAuthorized), outIsAuthorized, NULL);

    return err;

Document Revision History

Date	Notes
2006-04-11	New document that explains how to use the kQTPropertyClass_DRM properties with QuickTime media.