QuickTime 4 Reference
Determining What Kind of Tracks a Component Supports

The following code sample can be used to determine which track types a given movie export component supports.
Listing 2 Determining What Track Types a Movie Export Component Supports


 
QTAtomContainer container = nil;

ComponentDescription cd;

long count, i;



cd.componentType = MovieExportType;

cd.componentSubType = 0;

cd.componentManufacturer = 0;

cd.componentFlags = 0;

cd.componentFlagsMask = 0;



GetComponentPublicResourceList(kQTMovieExportTrackInfoResourceType, 1, 0, &cd, nil, nil, 

&container);



count = QTCountChildrenOfType(container, kParentAtomIsContainer, OSTypeConst('comp'));

for (i=1; i<=count; i++) {

    QTAtom compAtom, trkResourceAtom;

    Component c;



    compAtom = QTFindChildByIndex(container, kParentAtomIsContainer, OSTypeConst('comp'), i, 

(long *)&c);

    trkResourceAtom = QTFindChildByID(container, compAtom, 

kQTMovieExportTrackInfoResourceType, 1, nil);

    if (trkResourceAtom) {

        QTMovieExportSourceRecord **trkResource = (QTMovieExportSourceRecord **)NewHandle(0);

        long j;

        Boolean wantsSound = false, wantsVideo = false, wantsText = false, wantsMIDI = false;



        QTCopyAtomDataToHandle(container, trkResourceAtom, (Handle)trkResource);

        for (j=0; j<(**trkResource).count; j++) {

            OSType mType = (**trkResource).sourceArray[j].mediaType;

            long flags = (**trkResource).sourceArray[j].flags;



            wantsSound = wantsSound ||

                        ((mType == SoundMediaType) && (flags & 

kQTMovieExportSourceInfoIsMediaType));

            wantsVideo = wantsVideo || 

                        (((mType == VideoMediaType) && (flags & 

kQTMovieExportSourceInfoIsMediaType)) ||

                        ((mType == VisualMediaCharacteristic) && (flags & 

kQTMovieExportSourceInfoIsMediaCharacteristic)));

            wantsText = wantsText ||

                        ((mType == TextMediaType) && (flags & 

kQTMovieExportSourceInfoIsMediaType));

            wantsMIDI = wantsMIDI ||

                        ((mType == MusicMediaType) && (flags & 

kQTMovieExportSourceInfoIsMediaType));

        }



        if (wantsSound || wantsVideo) {

            ComponentDescription cd;

            char cc[5];



            GetComponentInfo(c, &cd, nil, nil, nil);

            cc[0] = 4;

            *(long *)&cc[1] = cd.componentSubType;

            DebugStr((StringPtr)cc);

            

        }



        DisposeHandle((Handle)trkResource);

    }

}



QTDisposeAtomContainer(container);