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QTCaptureDevice Class Reference

Overview

This class represents an available capture device. Each instance of QTCaptureDevice corresponds to a capture device that is connected or has been previously connected to the user’s computer during the lifetime of the application. Instances of QTCaptureDevice cannot be created directly. A single unique instance is created automatically whenever a device is connected to the computer and can be accessed using the deviceWithUniqueID: class method. An array of all currently connected devices can also be obtained using the inputDevices class method.

Devices can provide one or more stream of a given media type. Applications can search for devices that provide media of a specific type using the inputDevicesWithMediaType: and defaultInputDeviceWithMediaType: class methods. Table 1 details the media types supported by QTCaptureDevice and examples of devices that support them:

QTCaptureDevice objects can have extended attributes that applications can read using the attributeForKey: and deviceAttributes methods. Some attributes, for which the attributeIsReadOnly: method returns NO, can be edited using the setAttribute:forKey: and setDeviceAttributes: methods. In addition to these explicit methods, applications can use key-value coding to get and set extended attributes. For an object that supports a given attribute, valueForKey: will be functionally identical to attributeForKey:, and setValue:forKey: will be identical to setAttribute:forKey:. Applications wishing to observe changes for a given attribute can add a key-value observer where the key path is the attribute key.

Tasks

Finding Devices

• + defaultInputDeviceWithMediaType:
• + deviceWithUniqueID:
• + inputDevices
• + inputDevicesWithMediaType:

Using a Device

• – close
• – isConnected
• – isInUseByAnotherApplication
• – open:
• – isOpen

Getting Information About a Device

• – attributeForKey:
• – attributeIsReadOnly:
• – deviceAttributes
• – formatDescriptions
• – hasMediaType:
• – setAttribute:forKey:
• – setDeviceAttributes:
• – localizedDisplayName
• – modelUniqueID
• – uniqueID

Class Methods

defaultInputDeviceWithMediaType:

Returns a QTCaptureDevice instance for the default device connected to the user’s system of the given media type.

+ (QTCaptureDevice *)defaultInputDeviceWithMediaType:(NSString *)mediaType

Parameters

mediaType

The media type, such as QTMediaTypeVideo, QTMediaTypeSound, or QTMediaTypeMuxed, supported by the returned device.

Return Value

The default device with the given media type on the user’s system, or NIL if no device with that media type exists.

Discussion

This method returns the default device of the given media type connected to the user’s system. For example, for QTMediaTypeSound, this method will return the default sound input device selected in the Sound Preference Pane. If there is no device for the given media type, this method will return nil.

Media types are defined in QTMedia.h.

Availability

• Mac OS X v10.5 and later.

Related Sample Code

• QT Capture Widget

Declared In

QTCaptureDevice.h

deviceWithUniqueID:

Returns a QTCaptureDevice instance with the identifier device UID.

+ (QTCaptureDevice *)deviceWithUniqueID:(NSString *)deviceUID

Parameters

deviceUID

The unique identifier of the device instance to be returned.

Return Value

If a device with unique identifier deviceUID was connected to the computer at some point during the lifetime of the application, this method returns a QTCaptureDevice instance for that identifier. Otherwise, this method returns NIL.

Discussion

Every capture device available to the computer is assigned a unique identifier that persists on one computer across device connections and disconnections, as well as across reboots of the computer. This method can be used to recall or track the status of a specific device, even if it has been disconnected.

Availability

• Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

inputDevices

Returns an array of devices currently connected to the computer that can be used as input sources.

+ (NSArray *)inputDevices

Return Value

An NSArray of QTCaptureDevice instances for each connected device. If there are no available devices, the returned array will be empty.

Discussion

This method queries the device system and builds an array of QTCaptureDevice instances for input devices currently connected and available for capture. The returned array contains all devices that are available when the method is called. Applications should observe QTCaptureDeviceWasConnectedNotification and QTCaptureDeviceWasDisconnectedNotification to be notified when the list of available devices has changed.

Availability

• Mac OS X v10.5 and later.

Related Sample Code

• LiveVideoMixer3

Declared In

QTCaptureDevice.h

inputDevicesWithMediaType:

Returns an array of input devices currently connected to the computer that send a stream with the given media type.

+ (NSArray *)inputDevicesWithMediaType:(NSString *)mediaType

Parameters

mediaType

The media type, such as QTMediaTypeVideo, QTMediaTypeSound, or QTMediaTypeMuxed, supported by each returned device.

Return Value

An array of QTCaptureDevice instances for each connected device with the given media type. If there are no available devices, the returned array will be empty.

Discussion

This method queries the device system and builds an array of QTCaptureDevice instances for input devices that are currently connected and output streams of the given media type.

Media types are defined in QTMedia.h.

Availability

• Mac OS X v10.5 and later.

Related Sample Code

• QTRecorder

Declared In

QTCaptureDevice.h

Instance Methods

attributeForKey:

Returns a device attribute for the given key.

- (id)attributeForKey:(NSString *)attributeKey

Discussion

Use this method to get attributes of a device. The keys that can be used with this method are described in the Constants section. Applications using key-value coding can also get an attribute for a given key by passing that key to the NSObject valueForKey: method.

Availability

• Mac OS X v10.5 and later.

Related Sample Code

• LiveVideoMixer3
• QTRecorder

Declared In

QTCaptureDevice.h

attributeIsReadOnly:

Returns whether the given attribute for the device cannot be modified.

- (BOOL)attributeIsReadOnly:(NSString *)attributeKey

Return Value

Returns YES if the attribute cannot be modified; otherwise, NO.

Availability

• Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

close

Releases application control over the device acquired in the open: method.

- (void)close

Discussion

This method should be called to match each invocation of open: when an application no longer needs to use a device for capture. If a device is disconnected or turned off while it is open it will be closed automatically. Applications should check if a device has not been closed automatically by registering to receive QTCaptureDeviceWasDisconnectedNotification or by checking isOpen before manually closing the device using this method.

Applications can use key value coding with the @"connected" and @"inUseByAnotherApplication" keys to be notified of changes.

Availability

• Mac OS X v10.5 and later.

Related Sample Code

• QTRecorder

Declared In

QTCaptureDevice.h

deviceAttributes

Returns a dictionary of the device’s current attirbutes.

- (NSDictionary *)deviceAttributes

Return Value

An dictionary of attributes supported by the device.

Discussion

Applications can use this method to determine what attributes a specific device supports.

Availability

• Available in Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

formatDescriptions

Returns an array of stream formats currently in use by the device.

- (NSArray *)formatDescriptions

Return Value

An array of QTFormatDescription objects describing the current stream formats of the device.

Discussion

Applications can use this method to determine what kind of media the receiver outputs. Applications can be notified of format changes by registering to receive QTCaptureDeviceFormatDescriptionsWillChangeNotification and QTCaptureDeviceFormatDescriptionsDidChangeNotification notifications or by adding a key value observer for the key @"formatDescriptions" .

Availability

• Available in Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

hasMediaType:

Returns whether the receiver sends a stream with the given media type.

- (BOOL)hasMediaType:(NSString *)mediaType

Parameters

mediaType

A media type, such as QTMediaTypeVideo, QTMediaTypeSound, or QTMediaTypeMuxed.

Return Value

Returns YES if the device outputs the given media type, NO otherwise.

Discussion

Media types are defined in QTMedia.h.

Availability

• Available in Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

isConnected

Returns YES if the device is connected to the computer.

- (BOOL)isConnected

Return Value

Returns YES if the device is connected and available to applications; otherwise, NO.

Discussion

This method checks whether the receiver’s device is currently connected to the computer and available for use by applications.

Applications can use key value coding with the @"connected" and @"inUseByAnotherApplication" keys to be notified of changes.

Availability

• Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

isInUseByAnotherApplication

Returns YES is the device is connected, but being exclusively used by another application.

- (BOOL)isInUseByAnotherApplication

Return Value

Returns YES if another process has exclusive control over a connected device; otherwise, NO.

Discussion

If the device can only be accessed by one process at a time, this method checks if the process has exclusive control over the current process.

Applications can use key value coding with the @"connected" and @"inUseByAnotherApplication" keys to be notified of changes.

Availability

• Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

isOpen

Returns YES if the device is open in the current application.

- (BOOL)isOpen

Return Value

Returns YES if the device was previously opened by the receiver’s open: method. Returns NO otherwise.

Discussion

The method checks if the device was previously succcessfully opened with the receiver’s open: method. If this method returns YES, the device can be used immediately for capture.

Applications can use key value coding with the @"connected" and @"inUseByAnotherApplication" keys to be notified of changes.

Availability

• Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

localizedDisplayName

Returns a localized human-readable name for the receiver’s device.

- (NSString *)localizedDisplayName

Return Value

The localized name of the receiver’s device.

Discussion

This method can be used when displaying the name of a capture device in the user interface.

Availability

• Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

modelUniqueID

Returns the unique ID of the model of the receiver’s device.

- (NSString *)modelUniqueID

Return Value

The unique identifier of the model of device corresponding to the recevier.

Discussion

The unique identifier returned by this method is unique to all devices of the same model. The value is persistent across device connections and disconnections, and across different computers.

Availability

• Available in Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

open:

Attempts to give the application control over the device so that it can be used for capture.

- (BOOL)open:(NSError **)errorPtr

Parameters

errorPtr

If not equal to NIL, points to an NSError describing why the device could not be opened, or points to NIL if the device was opened successfully.

Return Value

Returns YES if the device was opened successfully; otherwise, NO.

Discussion

This method attempts to open the device for control by the current application. If the device is connected and no other processes have exclusive control over it, then the application starts using the device immediately, taking exclusive control of it if necessary. Otherwise, this method returns NO and sets errorPtr to point to an error describing why the device could not be opened. Applications that call open: should also call the close method to relinquish access to the device when it is no longer needed. Multiple calls to this method can be nested. Each call to this method must be matched by a call to close. Applications that capture from a device using QTCaptureDeviceInput must call this method before creating the QTCaptureDeviceInput to be used with the device. If a device is disconnected or turned off while it is open, it will be closed automatically.

Applications can use key value coding with the @"connected" and @"inUseByAnotherApplication" keys to be notified of changes.

Availability

• Available in Mac OS X v10.5 and later.

Related Sample Code

• QT Capture Widget
• QTRecorder

Declared In

QTCaptureDevice.h

setAttribute:forKey:

Sets a device attribute for the given key.

- (void)setAttribute:(id)attributeforKey :(NSString *)attributeKey

Discussion

Use this method to set attributes of a device. The keys that can be used with this method are described in the Constants section. This method raises an NSInvalidArgumentException if the attribute is read-only or not supported by the receiver. Applications using key value coding can also set an attribute for a given key by passing that key to the NSObject setValue:forKey: method.

Availability

• Available in Mac OS X v10.5 and later.

Related Sample Code

• QTRecorder

Declared In

QTCaptureDevice.h

setDeviceAttributes:

Sets attributes on the device from the key-value pairs in the given dictionary.

- (void)setDeviceAttributes:(NSDictionary *)deviceAttributes

Discussion

This method allows application to set multiple attributes on a device at once. This method raises an NSInvalidArgumentException if any of the attributes in the dictionary are read-only or not supported by the receiver. Applications using key-value coding can also set multiple attributes using the NSObject setValuesForKeysWithDictionary: method using attribute keys as keys in the dictionary.

Availability

• Available in Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

uniqueID

Returns the unique ID of the receiver’s device.

- (NSString *)uniqueID

Return Value

The unique identifier of the device corresponding to the receiver.

Discussion

The unique identifier returned by this method is persistent on one computer across device connections and disconnections, as well as across reboots of the computer. It can be passed to the deviceWithUniqueID: class method to get the QTCaptureDevice instance for the device with that unique identifier.

Availability

• Mac OS X v10.5 and later.

Declared In

QTCaptureDevice.h

Constants

Device Attributes

Constants for different device attributes.

NSString * const QTCaptureDeviceChangedAttributeKey;
NSString * const QTCaptureDeviceAvailableInputSourcesAttribute;
NSString * const QTCaptureDeviceInputSourceIdentifierAttribute;
NSString * const QTCaptureDeviceInputSourceIdentifierKey;
NSString * const QTCaptureDeviceInputSourceLocalizedDisplayNameKey;
NSString * const QTCaptureDeviceSuspendedAttribute;
NSString * const QTCaptureDeviceLinkedDevicesAttribute;
NSString * const QTCaptureDeviceLegacySequenceGrabberAttribute;
NSString * const QTCaptureDeviceAVCTransportControlsAttribute;
NSString * const QTCaptureDeviceAVCTransportControlsSpeedKey;
NSString * const QTCaptureDeviceAVCTransportControlsPlaybackModeKey;

Constants

QTCaptureDeviceChangedAttributeKey

Indicates the key of the attribute that changed. Used as a key in the userInfo dictionary passed to QTCaptureDeviceAttributeWillChangeNotification, and QTCaptureDeviceAttributeDidChangeNotification to indicate the key of the attribute that changed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAvailableInputSourcesAttribute

For devices with multiple possible input sources, returns an array of dictionaries describing each available input source. Some devices can capture data from one of multiple input sources (different input jacks on the same audio device, for example). The value is an NSArray of NSDictionary objects. The keys in each dictionary are described in Input Source Dictionary Keys. This string value can be used in key paths for key value coding, key value observing, and bindings.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceInputSourceIdentifierAttribute

Used to get and set the currently used input source for the device. Some devices can capture data from one of multiple input sources (different input jacks on the same audio device, for example). The value is an object returned by the QTCaptureDeviceInputSourceIdentifierKey key in one of the dictionaries returned by QTCaptureDeviceAvailableInputSourcesAttribute. This string value can be used in key paths for key value coding, key value observing, and bindings.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceInputSourceIdentifierKey

An object representing a unique ID for the input source. This ID is not guaranteed to persist between device connections or changes in device configuration. To set the input source for a device, set QTCaptureDeviceInputSourceIdentifierAttribute to the value returned by this key. This string value can be used in key paths for key value coding, key value observing, and bindings.

This key, along with the QTCaptureDeviceInputSourceLocalizedDisplayNameKey key, comprises the NSDictionary objects describing input sources returned by QTCaptureDeviceAvailableInputSourcesAttribute.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceInputSourceLocalizedDisplayNameKey

The localized display name of an input source, suitable for display in a user interface. This string value can be used in key paths for key value coding, key value observing, and bindings.

This key, along with the QTCaptureDeviceInputSourceIdentifierKey key, comprises the NSDictionary objects describing input sources returned by QTCaptureDeviceAvailableInputSourcesAttribute.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceSuspendedAttribute

Returns whether or not data capture on the device is suspended due to a feature on the device. For example, this attribute is YES for the external iSight when its privacy iris is closed, or for the internal iSight on a notebook when the notebook’s display is closed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceLinkedDevicesAttribute

Returns an array of QTCaptureDevice objects that, although they are separate devices on the system, are a part of the same physical device as the receiver. For example, for the external iSight camera, this attribute returns an array containing a QTCaptureDevice for the external iSight microphone.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceLegacySequenceGrabberAttribute

An NSValue interpreted as a ComponentInstance for the legacy sequence grabber component used by the device. Some older devices are opened and conreolled by legacy Sequence Grabber components. Applications that need to configure legacy devices directly through the Sequence Grabber configuration dialog can access an open component instance with this attribute.

This string value can be used in key paths for key-value coding, key-value observing, and bindings.

If the device is being used in a capture session, do not modify properties of the returned Sequence Grabber component (by displaying the configuration dialog, for example) while the session is running. Doing so will prevent the capture session from capturing more frames.

Available in Mac OS X v10.5 and later.

Not available to 64-bit applications.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsAttribute

For AVC devices that read data from linear media, such as tapes, specifies the mode and speed at which that media is playing.

The value is an NSDictionary with keys and values described under QTCaptureDevice AVC Transport Controls.

This string value can be used in key paths for key-value coding, key-value observing, and bindings.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsSpeedKey

Specifies the approximate rate at which the device runs through linear media. The value is an NSNumber interpreted as a QTCaptureDeviceAVCTransportControlsSpeed. This is one of the keys that comprise the NSDictionary that specifies the linear media playback mode and rate given by the QTCaptureDeviceAVCTransportControlsAttribute.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsPlaybackModeKey

A value provided with the QTCaptureDeviceAVCTransportControlsPlaybackModeKey key that specifies whether the device previews audio and displays video while it is running through linear media. QTCaptureDeviceAVCTransportControlsNotPlayingMode is equivalent to the Play mode on most cameras and tape decks, while QTCaptureDeviceAVCTransportControlsPlayingMode is equivalent to Stop on most cameras and tape decks. If the device is connected to a session, the video at the current location on the device’s media will only be captured if this attribute is set to QTCaptureDeviceAVCTransportControlsNotPlayingMode.

enum { QTCaptureDeviceAVCTransportControlsNotPlayingMode = 0, QTCaptureDeviceAVCTransportControlsPlayingMode = 1 };

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsSpeed

A value provided with the QTCaptureDeviceAVCTransportControlsSpeedKey key that specifies whether the device previews audio and displays video while it is running through linear media. The actual speed at which the media is run for a given value will depend on the manufacturer and model of the device, as well as the value of QTCaptureDeviceAVCTransportControlsPlaybackModeKey (in general, when QTCaptureDeviceAVCTransportControlsPlaybackModeKey is set to QTCaptureDeviceAVCTransportControlsNotPlayingMode, the media will run faster than when it is set to QTCaptureDeviceAVCTransportControlsPlayingMode).

Enumunerations

These are the values for the dictionary passed to QTCaptureDeviceAVCTransportControlsAttribute. For most cameras and tape decks, different speeds will affect the media speed.

enum {
   QTCaptureDeviceAVCTransportControlsFastestReverseSpeed  = -19000,
   QTCaptureDeviceAVCTransportControlsVeryFastReverseSpeed = -16000,
   QTCaptureDeviceAVCTransportControlsFastReverseSpeed     = -13000,
   QTCaptureDeviceAVCTransportControlsNormalReverseSpeed   = -10000,
   QTCaptureDeviceAVCTransportControlsSlowReverseSpeed     = -7000,
   QTCaptureDeviceAVCTransportControlsVerySlowReverseSpeed = -4000,
   QTCaptureDeviceAVCTransportControlsSlowestReverseSpeed  = -1000,
   QTCaptureDeviceAVCTransportControlsStoppedSpeed         = 0,
   QTCaptureDeviceAVCTransportControlsSlowestForwardSpeed  = 1000,
   QTCaptureDeviceAVCTransportControlsVerySlowForwardSpeed = 4000,
   QTCaptureDeviceAVCTransportControlsSlowForwardSpeed     = 7000,
   QTCaptureDeviceAVCTransportControlsNormalForwardSpeed   = 10000,
   QTCaptureDeviceAVCTransportControlsFastForwardSpeed     = 13000,
   QTCaptureDeviceAVCTransportControlsVeryFastForwardSpeed = 16000,
   QTCaptureDeviceAVCTransportControlsFastestForwardSpeed  = 19000,
};

Constants

QTCaptureDeviceAVCTransportControlsFastestReverseSpeed

Media runs in reverse at greater than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsVeryFastReverseSpeed

Media runs in reverse at greater than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsFastReverseSpeed

Media runs in reverse at greater than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsNormalReverseSpeed

Media runs in reverse at normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsSlowReverseSpeed

Media runs in reverse at less than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsVerySlowReverseSpeed

Media runs in reverse at less than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsSlowestReverseSpeed

Media runs in reverse at less than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsStoppedSpeed

Media is paused.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsSlowestForwardSpeed

Media runs forward at less than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsVerySlowForwardSpeed

Media runs forward at less than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsSlowForwardSpeed

Media runs forward at less than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsNormalForwardSpeed

Media runs forward at normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsFastForwardSpeed

Media runs forward at greater than than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsVeryFastForwardSpeed

Media runs forward at greater than than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

QTCaptureDeviceAVCTransportControlsFastestForwardSpeed

Media runs forward at greater than than normal speed.

Available in Mac OS X v10.5 and later.

Declared in QTCaptureDevice.h.

Notifications

QTCaptureDeviceWasConnectedNotification

Posted when a device is connected or turned on.

Availability

• QuickTime 7.2.1 and later

Declared In

QTCaptureDevice.h

QTCaptureDeviceWasDisconnectedNotification

Posted when a device is disconnected or turned off.

Availability

• QuickTime 7.2.1 and later

Declared In

QTCaptureDevice.h

QTCaptureDeviceFormatDescriptionsWillChangeNotification

Posted when the device's formats that are returned by the formatDescriptions method are about to change.

Availability

• QuickTime 7.2.1 and later

Declared In

QTCaptureDevice.h

QTCaptureDeviceFormatDescriptionsDidChangeNotification

Posted when the device’s formats that are returned by the formatDescriptions method have just changed.

Availability

• QuickTime 7.2.1 and later

Declared In

QTCaptureDevice.h

QTCaptureDeviceAttributeWillChangeNotification

Posted when one of the device's attributes is about to change.

The notification’s user info dictionary will contain the attribute key of the changed attribute for the key QTCaptureDeviceChangedAttributeKey.

Availability

• QuickTime 7.2.1 and later

Declared In

QTCaptureDevice.h

QTCaptureDeviceAttributeDidChangeNotification

Posted when the one of device’s attributes has changed.

The notification’s user info dictionary will contain the attribute key of the changed attribute for the key QTCaptureDeviceChangedAttributeKey.

Availability

• QuickTime 7.2.1 and later

Declared In

QTCaptureDevice.h

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