Digitizers are component that allow low–level interaction with the digitizing equipment. For example, video channels use video digitizer components, and sound channels use sound input drivers.
The QTPlgVideoDigitizer class lets you get access to video digitizer components.
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The QTPlgVideoDigitizer class constructors are called when you create a new instance of the class, while the ˜QTPlgVideoDigitizer class destructor, is called automatically when the class is no more in use. Also, you can invoke the class destructor by setting the instance of the class to nil. Usually you deal with QTPlgVideoDigitizer objects obtained from .
Once a new class instance is returned, it is good practice to check the class property to be sure that the new object can be used. See the QTPlgVideoDigitizer’s validity conditions for more details.
The class provides you with the following initializer methods:
(component as )
The new class instance will try to open a connection to the video digitizer component specified by the
component parameter;
you can obtain a list of all of the currently installed video digitizers by using the
method of the
module,
passing to it the appropriate
.
If the connection succeeds, the properties of the class will be initialized to the default settings of the selected
video digitizer
(other as QTPlgVideoDigitizer)
This is the copy constructor. The properties of the object to be copied will be used to initialize the
new class instance properties
specifies the number of input video sources that the video digitizer component supports
establishes the input video source for the video digitizer component; valid values range from
0 to –1
returns a dictionary containing a description for each parameter of video digitizer whose default is known. The dictionary may be empty if
defaults cannot be determined
returns a dictionary containing descriptions of the current capabilities of a video digitizer and the state of its parameters.
If the video digitizer has not implemented any parameters the dictionary is empty.
specifies the current digitizer rectangle
indicates that the video digitizer supports National Television System Committee (NTSC) format input video signals.
This property is set to true if the digitizer component supports NTSC video.
indicates that the video digitizer component supports Phase Alternation Line (PAL) format input video signals.
This property is set to true if the digitizer component supports PAL video
indicates that the video digitizer component supports Systeme Electronique Couleur avec Memoire (SECAM) format
input video signals.
This property is set to true if the digitizer component supports SECAM video
indicates that the video digitizer component supports genlock; that is, the digitizer can derive its timing from an external
time base. This property is set to true if the digitizer component supports genlock
indicates that the video digitizer component supports composite input video.
This property is set to true if the digitizer component supports composite input
indicates that the video digitizer component supports s–video input video.
This property is set to true if the digitizer component supports s–video input
indicates that the video digitizer component supports RGB input video.
This property is set to true if the digitizer component supports RGB input.
indicates that the video digitizer component is locked onto the input signal. If this property is set to true,
the digitizer component detects either vertical or horizontal signal lock
(type as )
as
use this method to obtain the current capabilities and state information of the video digitizer parameter identified by the
type parameter. Which object is returned from this method depends on the type of the selected parameter; you can use the
isA RealBasic operator to find about the type of the
class instance obtained
You can get information about whether the default and current values of the
supported video digitizer parameters by inspecting the dictionaries returned from the
and
class properties respectively
(param as )
use this method to change the state of a video digitizer’s parameter. You can obtain the
current capabilities and state information of the video digitizer parameter by using the
class method
(i as integer) as string
use this method to obtain a descriptive string of the format of the video signal provided by a specified video input source. You can
specify the index of the input source by the i parameter; valid values for this index range from
0 to –1
(signal as integer)
you can use this method to specify the input signaling standard to digitize; you indicate the required input signaling by setting the
signal parameter to one of the
provided by the class
(signal as integer)
as
use this method to obtain size and location information for the active source rectangle used by the video digitizer component; you indicate
the input video signal associated with this rectangle by setting the signal parameter to one of the
provided by the class
(signal as integer)
as
use this method to obtain size and location information for the vertical blanking rectangle associated to the video digitizer component;
you indicate
the input video signal associated with this rectangle by setting the signal parameter to one of the
provided by the class
(signal as integer)
as
use this method to obtain size and location information for the maximum source rectangle supported by the video digitizer component;
you indicate
the input video signal associated with this rectangle by setting the signal parameter to one of the
provided by the class
identifies the National Television System Committee (NTSC) format input video signals
identifies the Phase Alternation Line (PAL) format input video signals
identifies the Systeme Electronique Couleur avec Memoire (SECAM) format input video signals