QTCaptureView retain count problem and setting iSight's focus (macro)

FROM : shige02
DATE : Mon Jan 07 16:53:50 2008

Hello, all.

1st, I wondering why QTCaptureView does not retain sat session?
Retain count is still 1 after setCaptureSession: call.

Debugger console shows:
2008-01-08 00:23:51.646 QuickCap[33248:10b] retainCount 1 1

int retainCount = [session retainCount];
[captureView setCaptureSession:session];
NSLog(@"retainCount %d %d", retainCount, [session retainCount]);

2nd, how can I set iSight's (buit-in) focus?
With sequece grabber (SGChannel), I use following code, (from 
MyBarcodeScanner.m, http://www.bruji.com/cocoa/barcode.html) but it 
seems not works on my MacBook.

// Set the focus value helps with external iSights
// Thanks to Wil Shipley for the focus code:
// http://lists.apple.com/archives/quicktime-api/2004/Mar/msg00257.html
long quickTimeVersion = 0;
Gestalt(gestaltQuickTime, &quickTimeVersion);
if (video && (quickTimeVersion & 0xFFFFFF00) > 0x0708000) {
   // What to set the focus of the external iSights to
   const QTFloatSingle CAMERA_FOCUS = 0.35;

   QTAtomContainer iidcFeaturesAtomContainer = NULL;
   QTAtom featureAtom = 0;
   QTAtom typeAndIDAtom = 0;
   QTAtom featureSettingsAtom = 0;
   
   QTNewAtomContainer(&iidcFeaturesAtomContainer);
   
   QTInsertChild(iidcFeaturesAtomContainer, // QTAtomContainer container
                 kParentAtomIsContainer, // QTAtom parentAtom
                 vdIIDCAtomTypeFeature, // QTAtomType atomType
                 1, // QTAtomID id
                 0, // short index
                 0, // long dataSize
                 nil, // void *data
                 &featureAtom); // QTAtom *newAtom
   
   VDIIDCFeatureAtomTypeAndID featureAtomTypeAndID = {
       .feature  = vdIIDCFeatureFocus, /* OSType of feature*/
       .group    = vdIIDCGroupMechanics, /* OSType of group that feature is 
categorized into*/
       .name    = {5, 'F', 'o', 'c', 'u', 's'}, /* Str255, Name of this 
feature*/
       .atomType = vdIIDCAtomTypeFeatureSettings, /* Atom type which 
contains feature's settings*/
       .atomID  = vdIIDCAtomIDFeatureSettings /* Atom ID which contains 
feature's settings*/
   };
   
   QTInsertChild(iidcFeaturesAtomContainer,
                 featureAtom,
                 vdIIDCAtomTypeFeatureAtomTypeAndID,
                 vdIIDCAtomIDFeatureAtomTypeAndID,
                 0,
                 sizeof(featureAtomTypeAndID),
                 &featureAtomTypeAndID,
                 &typeAndIDAtom);
   
   VDIIDCFeatureSettings featureSettings = {
       .capabilities = {
           .flags = 0, // UInt32
           .rawMinimum = 0, // UInt16
           .rawMaximum = 0, // UInt16
           .absoluteMinimum = 0.0, // QTFloatSingle
           .absoluteMaximum = 0.0  // QTFloatSingle
       },
       .state = {
           .flags = vdIIDCFeatureFlagOn | vdIIDCFeatureFlagManual | 
vdIIDCFeatureFlagRawControl, // UInt32
           .value = CAMERA_FOCUS // QTFloatSingle
       }
   };
   QTInsertChild(iidcFeaturesAtomContainer,
                 featureAtom,
                 vdIIDCAtomTypeFeatureSettings,
                 vdIIDCAtomIDFeatureSettings,
                 0,
                 sizeof(featureSettings),
                 &featureSettings,
                 &featureSettingsAtom);
   
   /*
    *  VDIIDCSetFeatures()
    *
    *  Availability:
    *    Mac OS X:        in version 10.3 (or QuickTime 6.4) and later 
in QuickTime.framework
    */
   (void)VDIIDCSetFeatures(SGGetVideoDigitizerComponent(video),
                           iidcFeaturesAtomContainer);
}