Quartz Composer / カメラデバイスを指定して動画を取得するパッチ

追記(2011/2/12): 公開してみた．

---

動機
'Video Input'パッチだとカメラの指定がSettingでしかできないのでPublishできないみたい．
外部からカメラ切り替えられるようにしたら便利っぽそう．

やってみた
１．XcodeのQuartzComposerのPlug-inテンプレートから作成
２．QTKit.frameworkを追加
３．CaptureWithDevicePlugIn.h

#import <Quartz/Quartz.h>
#import <QTKit/QTKit.h>
@interface OutputImageProvider : NSObject <QCPlugInOutputImageProvider> 
{  
 CVImageBufferRef _imageBuffer;
 NSBitmapImageRep *_bitmapImageRep;
}
- (id) initWithImageSource:(CVImageBufferRef)imageBuffer;
@end
@interface CaptureWithDevicePlugIn : QCPlugIn
{
 QTCaptureSession                    *mCaptureSession;
    QTCaptureDeviceInput                *mCaptureDeviceInput;
    QTCaptureDecompressedVideoOutput    *mCaptureDecompressedVideoOutput;
    
    CVImageBufferRef                    mCurrentImageBuffer;
 
 NSUInteger       _currentDevice;
}
@property   NSUInteger inputDevice;
@property(assign) id<QCPlugInOutputImageProvider> outputImage; 
@end

４．CaptureWithDevicePlugIn.m

#import <OpenGL/CGLMacro.h>
#import "CaptureWithDevicePlugIn.h"

#define kQCPlugIn_Name    @"CaptureWithDevice"
#define kQCPlugIn_Description  @"CaptureWithDevice description"

@implementation CaptureWithDevicePlugIn
@dynamic inputDevice;
@dynamic outputImage;
+ (NSDictionary*) attributes
{
 return [NSDictionary dictionaryWithObjectsAndKeys:
   kQCPlugIn_Name, QCPlugInAttributeNameKey, 
   kQCPlugIn_Description, QCPlugInAttributeDescriptionKey,
   nil];
}
+ (NSDictionary*) attributesForPropertyPortWithKey:(NSString*)key
{  
 if([key isEqualToString:@"inputDevice"]) {
  NSArray *devices= [QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeVideo];
  NSMutableArray *deviceNames= [NSMutableArray array];
  int i, ic= [devices count];
  for(i= 0; i<ic; i++) {
   [deviceNames addObject:[[devices objectAtIndex:i] description]];
  }
  return [NSDictionary dictionaryWithObjectsAndKeys:
    @"Device", QCPortAttributeNameKey,
    QCPortTypeIndex,QCPortAttributeTypeKey,
    [NSNumber numberWithInt:0], QCPortAttributeMinimumValueKey,
    deviceNames, QCPortAttributeMenuItemsKey,
    [NSNumber numberWithInt:ic-1], QCPortAttributeMaximumValueKey,
    nil];
 }
 if([key isEqualToString:@"outputImage"])
  return [NSDictionary dictionaryWithObjectsAndKeys:
    @"Video Image", QCPortAttributeNameKey,
    nil];
 return nil;
}
+ (QCPlugInExecutionMode) executionMode
{
 return kQCPlugInExecutionModeProvider;
}

+ (QCPlugInTimeMode) timeMode
{
 return kQCPlugInTimeModeIdle;
}

- (id) init
{
 if(self = [super init]) {
  [[NSNotificationCenter defaultCenter] addObserver:self 
             selector:@selector(_devicesDidChange:) 
              name:QTCaptureDeviceWasConnectedNotification 
               object:nil];
  [[NSNotificationCenter defaultCenter] addObserver:self 
             selector:@selector(_devicesDidChange:) 
              name:QTCaptureDeviceWasDisconnectedNotification 
               object:nil];
 }
 return self;
}

- (void) finalize
{
 [super finalize];
}

- (void) dealloc
{
 if (mCaptureSession) {
  [mCaptureSession release];
  [mCaptureDeviceInput release];
  [mCaptureDecompressedVideoOutput release];
 }
 [[NSNotificationCenter defaultCenter] removeObserver:self];
 [super dealloc];
}

@end

@implementation CaptureWithDevicePlugIn (Execution)

- (BOOL) startExecution:(id<QCPlugInContext>)context
{
 return YES;
}

- (void) enableExecution:(id<QCPlugInContext>)context
{
}
- (BOOL) execute:(id<QCPlugInContext>)context atTime:(NSTimeInterval)time withArguments:(NSDictionary*)arguments
{
 if (!mCaptureSession || [mCaptureSession isRunning]==NO || _currentDevice!=self.inputDevice){
  NSError *error = nil;
  BOOL success;
        
  NSArray *devices= [QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeVideo];
  NSUInteger d= self.inputDevice;
  if (!(d<[devices count])) {
   d= 0;
  }
  QTCaptureDevice *device = [devices objectAtIndex:d];
        success = [device open:&error];
        if (!success) {
   self.outputImage = nil; 
            return YES;
        }
        
  [mCaptureSession release];
        mCaptureSession = [[QTCaptureSession alloc] init];
  
        mCaptureDeviceInput = [[QTCaptureDeviceInput alloc] initWithDevice:device];
        success = [mCaptureSession addInput:mCaptureDeviceInput error:&error];
  
        if (!success) {
   self.outputImage = nil; 
   [mCaptureSession release];
   mCaptureSession= nil;
   [mCaptureDeviceInput release];
            return YES;
        }
        
        mCaptureDecompressedVideoOutput = [[QTCaptureDecompressedVideoOutput alloc] init];
        [mCaptureDecompressedVideoOutput setDelegate:self];
        success = [mCaptureSession addOutput:mCaptureDecompressedVideoOutput error:&error];
  
        if (!success) {
   self.outputImage = nil; 
   [mCaptureSession release];
   mCaptureSession= nil;
   [mCaptureDeviceInput release];
   [mCaptureDecompressedVideoOutput release];
            return YES;
        }
  
        [mCaptureSession startRunning]; 
  _currentDevice= self.inputDevice;
 }
 
 CVImageBufferRef imageBuffer;
    
    @synchronized (self) {
        imageBuffer = CVBufferRetain(mCurrentImageBuffer);
    }
    
    if (imageBuffer) {
  OutputImageProvider *provider= [[OutputImageProvider alloc] initWithImageSource:imageBuffer];
  
  if(provider == nil) 
   return NO; 
  self.outputImage = provider; 
  [provider release]; 
 } 
 else 
  self.outputImage = nil; 
 
 return YES; 
}

- (void) disableExecution:(id<QCPlugInContext>)context
{
}

- (void) stopExecution:(id<QCPlugInContext>)context
{
}
- (void)captureOutput:(QTCaptureOutput *)captureOutput
  didOutputVideoFrame:(CVImageBufferRef)videoFrame 
  withSampleBuffer:(QTSampleBuffer *)sampleBuffer 
    fromConnection:(QTCaptureConnection *)connection
{
    CVImageBufferRef imageBufferToRelease;
    CVBufferRetain(videoFrame);
    @synchronized (self) {
        imageBufferToRelease = mCurrentImageBuffer;
        mCurrentImageBuffer = videoFrame;
    }
    CVBufferRelease(imageBufferToRelease);
}
- (void)_devicesDidChange:(NSNotification *)aNotification
{
}
@end
@implementation OutputImageProvider
- (id) initWithImageSource:(CVImageBufferRef)imageBuffer
{ 
 if(!imageBuffer) { 
  [self release]; 
  return nil; 
 } 
 if(self = [super init]) {
  _imageBuffer= imageBuffer;
 } 
 return self; 
} 
- (void) dealloc 
{ 
 [_bitmapImageRep release];
 CVBufferRelease(_imageBuffer);
 
 [super dealloc]; 
} 
- (NSRect) imageBounds 
{ 
#if defined(__LP64__) && __LP64__
 return CVImageBufferGetCleanRect(_imageBuffer);
#else
 CGRect r= CVImageBufferGetCleanRect(_imageBuffer);
 return NSMakeRect(r.origin.x, r.origin.y, r.size.width, r.size.height); 
#endif
}
- (CGColorSpaceRef)imageColorSpace 
{ 
 return CVImageBufferGetColorSpace(_imageBuffer); 
} 
- (NSArray*) supportedBufferPixelFormats 
{ 
 return [NSArray arrayWithObjects:
   QCPlugInPixelFormatARGB8, 
   QCPlugInPixelFormatBGRA8, 
   nil]; 
} 
- (BOOL) renderToBuffer:(void *)baseAddress 
  withBytesPerRow:(NSUInteger)rowBytes 
   pixelFormat:(NSString *)format 
     forBounds:(NSRect)bounds 
{
 _bitmapImageRep= [[NSBitmapImageRep alloc] initWithCIImage:[CIImage imageWithCVImageBuffer:_imageBuffer]];
 memcpy(baseAddress, [_bitmapImageRep bitmapData], rowBytes*bounds.size.height);
 return YES; 
}
@end

結果

カメラ2つ(30万画素)をつないでからQCを立ち上げたらこのパッチで２つを含めて切り替えて使えた．

参考
StillMotion
感謝