This page provides the documentation of the HALCON MediaFoundation image acquisition interface, which is based on GenICam GenTL and the Microsoft Media Foundation. Registered customers can download the latest revision of this interface from the MVTec WWW server.
The interface internally contains a GenTL producer based on Microsoft Media Foundation which is referred to as 'Media Foundation Producer' in this document.

• Windows 10 or newer operating system.
• HALCON image acquisition interface hAcqMediaFoundation.dll or hAcqMediaFoundationxl.dll, respectively. If you have properly installed the interface, all these DLLs should reside in bin\%HALCONARCH% within the HALCON base directory %HALCONROOT% you have chosen during the installation of HALCON.
• GenICam GenApi. The corresponding files are part of the HALCON MediaFoundation package and are located in the directory genicam within the HALCON base directory %HALCONROOT%. See section GenICam GenApi for more details.
• A Media Foundation compatible capture device and a successfully installed driver for that device.

MVTec interfaces for digital I/O and image acquisition are always compatible to a range of HALCON versions. Therefore, the versioning scheme both describes the compatibility of the interface and also the revision of the interface itself. An interface version always consists of three numbers, separated by dots, i.e. 20.11.5. The first two numbers describe the minimum HALCON version the interface is compatible with. For the example version 20.11.5 this means that the interface is compatible with all HALCON versions since HALCON 20.11. The last number describes the revision of the interface, in this example this is revision 5.

Only when installing or updating the interface manually follow these steps:

• Windows: Extract the archive containing the interface files to the HALCON base directory %HALCONROOT% (Note: Administrator privileges may be required for this step). Additionally, you have to move the interface examples to the directory %HALCONEXAMPLES% manually.

• Multiple capture devices.
• Synchronous and asynchronous grabbing.
• Support of feature persistence.
• Support camera settings control.

• Only the following Microsoft Media Foundation video formats are fully supported: MFVideoFormat_L8, MFVideoFormat_L16, MFVideoFormat_RGB24, MFVideoFormat_RGB32, MFVideoFormat_YUY2, MFVideoFormat_NV12, MFVideoFormat_NV21, and MFVideoFormat_MJPG.
• No triggering.
• Only AcquisitionMode 'Continuous' is available.
• The following SFNC features are read-only: Height, Width and AcquisitionFrameRate.

The connection to the (acquisition) device is established through the open_framegrabber operator. The operator provides a set of parameters allowing to configure the basic properties of the device and how the HALCON MediaFoundation interface controls it – see corresponding section. Some of the parameters can be also modified at runtime through set_framegrabber_param. This section concentrates solely on the 'Device' parameter of open_framegrabber, identifying the device (usually camera) that should be opened.
A connection to the device accessible through the MediaFoundation interface is established using the device ID which is guaranteed to be unique per device and stays persistent across multiple sessions, as long as the device remains connected to the same system and USB port. The list of all devices currently available in the system can be obtained using info_framegrabber parameter 'device' or 'info_boards' – see corresponding section. Both parameters return a list of devices, each specified using entities in the format ' | device:<device id> | unique_name:<unique name> | ... '. To increase compatibility with other HALCON image acquisition Interfaces they are both listed. The full string (obtained from the info_framegrabber call) can be directly used for the 'Device' parameter of open_framegrabber, which uses the same format. Only the ' | device:<device id>' string entry is mandatory for open_framegrabber, the others might be omitted.

When a pure string without any 'token:' and without the ' | ' separator is used, it is interpreted directly as the device ID.
As a special case, the string 'default' can be used – in this case the HALCON acquisition interface will use the first available device (devices currently reported as non-accessible will be skipped). However this can result in non deterministic opening of devices when multiple devices are connected to the system.

• This interface uses GenApi version 3.4.2, for more details refer to the GenICam homepage. The corresponding files are part of the HALCON runtime installation and are located in the directory genicam within the HALCON base directory %HALCONROOT% or $HALCONROOT, respectively. This version is the same as the officially released version at the time of writing.
• The HALCON MediaFoundation interface sets all necessary environment variables on its own and ignores other installed GenICam packages by default.
  If you want to use another GenICam package, you need to set the environment variable HALCON_USE_EXTERNAL_GENAPI. This skips the step of setting all necessary variables and paths internally, so you have to make sure they are set correctly. Please note that it might not be possible to use different GenApi versions with different interfaces at the same time and that you must use the required GenApi version for this interface.
• The caching of device XML files is activated to speed up processing, writing to a temporary directory subject to availability of %TEMP%, %TMP%, $TMPDIR, /tmp or %HALCONROOT%.
• The remote device control features as well as the Media Foundation Producer control features of this interface are controlled via GenApi.

The features of a device or Media Foundation Producer are described by GenICam feature description files (XML files) that are automatically parsed and offered to the user. The HALCON MediaFoundation image acquisition interface provides access to the features exposed through the following GenICam feature description files:

• Features of the connected device are wrapped by the Media Foundation Producer and presented via a GenICam compatible XML file. Names for those features follow the SFNC recommendation as far as applicable.
• Features of the Media Foundation Producer are exposed through a set of GenICam description files, one for each internal entity to control the device tree:
  • The "system" – representing the overall behavior of the acquisition interface
  • The interface used to connect the device to the system.
  • A proxy (called "local device") to the device, controlling the Media Foundation Producer view of the device.
  • The data stream used for the acquisition (if the device provides any data streams).

In most cases the GenICam description files are provided by the device and the Media Foundation Producer. It is possible to store a copy of these files corresponding to an open connection by using the parameter 'do_write_configuration' (see set_framegrabber_param). The command will write all the GenICam description files and an "ini" file (details in set_framegrabber_param) with various information, including the location of the written GenICam description files, in the following format:

 
RemoteFile=%PATH_TO_GENICAM_FILE_OF_THE_DEVICE% 
SystemFile=%PATH_TO_GENICAM_FILE_OF_THE_SYSTEM_MODULE% 
InterfaceFile=%PATH_TO_GENICAM_FILE_OF_THE_INTERFACE_MODULE% 
DeviceFile=%PATH_TO_GENICAM_FILE_OF_THE_LOCAL_DEVICE_MODULE% 
StreamFile=%PATH_TO_GENICAM_FILE_OF_THE_STREAM_MODULE% 

The same ini-file format can be reused to force the HALCON acquisition interface to load an alternative XML file for one or more of these entities. This can be useful, e.g., for updates or troubleshooting. The files listed in the ini file will be used for the given entity instead of the original ones. For the entities excluded from the ini file, the GenICam description file will be searched and loaded the usual way. To apply the ini file, pass its full path to open_framegrabber in the 'CameraType' parameter.

Note that the ini-file can be reused also for other purposes such as storing/restoring configuration as described in Parameters – Persisting Device Status. Be aware that when persistence files are specified, they have priority over other explicit settings passed to open_framegrabber.

The following groups of parameters exist:

• Internal parameters of the MVTec GenTL Consumer itself (GenICamTL acquisition interface). These are named following the "underscore" naming style, e.g., color_space, and are all lowercase. However, MVTec EasyParams are prefixed with "[Consumer]", e.g., [Consumer]gain.
• GenICam-based parameters of the device, usually a camera, use by convention the "CamelCase" style, e.g., ExposureTime.
• GenICam-based parameters of the individual Media Foundation Producer modules (system, interface, device and data stream) use by convention the same style but are prefixed with the module name in square brackets. Beware that the system and interface modules might potentially be shared by multiple opened devices, so changing their configuration might have side effects on other connections as well. The following prefixes are used:
  • "[System]", e.g., [System]TLVendorName.
  • "[Interface]", e.g., [Interface]InterfaceType.
  • "[Device]", e.g., [Device]DeviceID.
  • "[Stream]", e.g., [Stream]StreamBufferHandlingMode.

Microsoft Media Foundation does not provide any mechanism to access the camera settings. Therefore, DirectShow IAMCameraControl and IAMVideoProcAmp interfaces are used for this purpose. All CameraControl and VideoProcAmp properties are implemented and accessible as remote device features. Each DirectShow parameter has an extra auto remote device feature to control its automatic mode, except for VideoProcAmp_BacklightCompensation and VideoProcAmp_ColorEnable. For instance, VideoProcAmp_Gamma is represented by the remote device feature Gamma and GammaAuto.
The availability of the parameters depends on the connected device.
For detailed information, check the parameter description in the parameters list.

The MVTec EasyParams is a group of MVTec GenTL Consumer parameters based on the regular GenICam features of the device. These parameters allow easy access to the most commonly used camera parameters.
The list of EasyParams can be obtained calling 'available_easyparam_names'. Note that 'available_param_names' does not include the EasyParams. The MVTec EasyParams start with the prefix [Consumer], indicating they are internal parameters of the HALCON GenTL consumer itself.
Since HALCON 22.11 they are available via an own tab in the HDevelop Image Acquisition Assistant.
If your device does not support one of the EasyParams, querying its access will return 'ni' (not implemented). If instead 'na' (not available) is returned, the EasyParam is supported but currently not available, e.g., it depends on the current state of another EasyParam or the access of one or more GenICam features, or because the image acquisition is running. In the latter case, use set_framegrabber_param(..., 'do_abort_grab', ...) to stop the acquisition.
List of MVTec EasyParams:

• General device information:
  • [Consumer]info_general
• Exposure feature:
  • [Consumer]exposure_auto
  • [Consumer]exposure
• Gain feature:
  • [Consumer]gain_auto
  • [Consumer]gain

Detailed information of each MVTec EasyParam can be found in sections about getting framegrabber parameters and setting framegrabber parameters.

HALCON native parameter types are

• integer – signed integer, 64-bit on 64-bit platforms, 32-bit on 32-bit ones
• real – floating point type
• string – classical string

When accessing GenICam-based features, the GenICam data types must be mapped to the parameter types recognized by HALCON. GenICam offers the following types:

• IInteger – integer value, mapped directly to HALCON's integer parameter type. It will also accept real parameters. When the GenICam feature in question has a representation associated that identifies it as IPV4Address, MACAddress or HexNumber, the corresponding string representation will also be accepted. It should be highlighted that a problem can occur when running HALCON on a 32-bit platform (where integer parameters are 32-bit wide) and accessing a GenICam feature that is naturally 64-bit. In such cases the full range of the feature will not be available to the application and its value might be truncated. Also the sign of the parameter might be misinterpreted. To solve this problem, the parameter 'split_param_values_into_dwords' can be used. This maps the 64-bit IInteger value into two 32-bit integer values and vice versa.
• IFloat – floating point value, mapped directly to HALCON's real parameter type. It will also accept integer parameters.
• IString – string value, mapped directly to HALCON's string parameter type.
• IBoolean – boolean type is handled through HALCON's integer parameters, a value of 0 (zero) means logical false, other values mean logical true.
• IEnumeration – enumeration is a type that allows selecting from a set of values that are primarily identified by their name (the values are called 'enum entries'). Enumerations are interfaced through HALCON's string parameter type, while the enum entry names are used as the parameter values.
• ICommand – The command type allows to "execute" actions. To execute a command, use set_framegrabber_param with an integer parameter of any value (the value is ignored). Some commands' execution might take longer time and the command provides feedback when it is done. To query the status, use get_framegrabber_param for that command. It will return an integer value of 1 if it "is done" (command execution has finished), 0 if it has not finished yet. Note that if some other features are designed to be dependent on the command, querying the "is done" status might be essential to get the depending features invalidated (and updated with new values) as soon as the command execution finishes.
• IRegister – The register data type is used for plain memory blobs that cannot be mapped to any other data type. They are interfaced through HALCON's string parameter type, the register value is the hexadecimal string representation of the register's memory.

The current status of the acquisition device settings (values of all the parameters defining its working state) might be persisted while no acquisition is active, i.e. before grab_image_start or grab_image_async or after set_framegrabber_param(..., 'do_abort_grab', 1). This applies not only to actual device parameters, but also to parameters configuring the Media Foundation Producer and internal parameters of the MediaFoundation image acquisition interface. Device parameters are usually kept until the device is powered down. The Media Foundation Producer modules and the Consumer parameters are kept until close_framegrabber is called. To indicate which parameters to persist, use the parameter 'settings_selector'. The persistence functionality consists of two steps, storing the current configuration to a file and later re-loading it back to the device. The selected module settings, indicated by 'settings_selector', can be stored using the 'do_write_settings' parameter and re-loaded later using the 'do_load_settings' parameter, specifying the desired persistence file path in both cases. To query if a feature can be persisted use the postfix '_streamable'.

Note that while the format of the files is intentionally human readable and the files can be hand-modified if desired, such modifications should be done with care by someone familiar with the GenICam persistence functionality internals and given device. Improper modifications of the files can lead to errors when using it.

The persistence related operations might be blocked by the device and/or Media Foundation Producer based on the current state, for example while an acquisition is in progress.

The same persistence files can be applied to the entire set of devices of the same type and firmware version. Applying the persistence files to a device of another type or using even different firmware version will probably lead to inconsistencies or will even fail completely .

Apart from the 'do_write_settings', the feature persistence file will also be written together with the ini file documented in the section Selection of GenICam Feature Description File(s) - using parameter 'do_write_configuration'. This command will generate extended version of the persistence file, storing not only the current device configuration, but also contents of its user sets and sequencer sets (if the device supports them). Additionally, it will also generate persistence files for all the Media Foundation Producer modules (system, interface, device and data stream). The persistence file entries in the ini file will have the format

 
RemotePersistence=%PATH_TO_PERSISTENCE_FILE_OF_THE_DEVICE% 
SystemPersistence=%PATH_TO_PERSISTENCE_FILE_OF_THE_SYSTEM_MODULE% 
InterfacePersistence=%PATH_TO_PERSISTENCE_FILE_OF_THE_INTERFACE_MODULE% 
DevicePersistence=%PATH_TO_PERSISTENCE_FILE_OF_THE_LOCAL_DEVICE_MODULE% 
StreamPersistence=%PATH_TO_PERSISTENCE_FILE_OF_THE_STREAM_MODULE% 

The image acquisition can be either synchronous (grab_image/grab_data) or asynchronous (grab_image_start/grab_image_async/grab_data_async), see the reference documentation of the operators.
The interface fully configures and controls the acquisition process on the camera. Note that some of the camera features might be locked by GenICam when an acquisition is active.
With synchronous grab (grab_image/grab_data), a new acquisition is started internally for each image, so that the application always gets a new image. Before delivering the image, the acquisition is stopped again, so between individual grab_image/grab_data calls, all acquisition related features remain unlocked.
With asynchronous grabbing, started explicitly by grab_image_start or implicitly by grab_image_async/grab_data_async, the interface keeps the acquisition running internally, collecting further images to be delivered through future grab_image_async/grab_data_async calls. The acquisition related features are locked, until the acquisition is stopped using set_framegrabber_param(..., 'do_abort_grab', ...).
The HALCON acquisition interface properly recognizes the 'Continuous', 'SingleFrame' and 'MultiFrame' acquisition modes configured on the device and adjusts the acquisition control logic accordingly.
Furthermore, the interface takes over exclusive access to several remote device features essential for the acquisition control (AcquisitionStart, AcquisitionStop, AcquisitionAbort, TLParamsLocked). The user application has no direct way to control these features.
The differences between the "image" and "data" version of the grab operators is documented in Acquisition – Grab Operators.

During open_framegrabber the best Microsoft Media Foundation media type is selected, meaning an RGB (if available) video subtype with the widest width, highest height and fastest frame rate combination. See 'MFMediaType' parameter for further information.

The interface allocates 4 buffers for the acquisition engine by default (the number of buffers can be changed through the 'Generic' parameter of open_framegrabber).
Whenever a new image is acquired successfully and passed to the application as a HALCON image, the interface keeps the buffer locked (not returning it to the acquisition engine) until a new grab-related operator is called by the application or the acquisition is aborted using set_framegrabber_param(..., 'do_abort_grab', ...). During this period, it is fully safe to query information about this "last acquired" buffer – for example query buffer properties through get_framegrabber_param parameters such as 'buffer_timestamp', 'buffer_is_incomplete', 'image_width' and 'image_height'.
When a new grab-related operator is called by the application, the interface returns the buffer to the acquisition engine and buffer-related queries are not valid anymore.

It can happen, that the camera is temporarily or constantly acquiring data in higher speed than the application is processing them. In such case the streaming engine of the Media Foundation Producer decides how to treat the acquired buffers based on the '[Stream]StreamBufferHandlingMode' parameter.

The acquisition interface provides two mechanisms for acquisition of the image (or other) data from the device, grab_image/grab_image_async and grab_data/grab_data_async. Each of them might be more suitable for different use cases. Internally, both mechanisms work exactly the same (in particular how they acquire and process the data from the device), they differ in the way how the outputs are provided to the application.
The "traditional" grab_image/grab_image_async operators are still well suitable in simple use cases when just a single 2D image is acquired from the device. It is also currently used e.g. by the HDevelop's Image Acquisition Assistant. However, in case when the device is streaming more complex data structures, such as 3D data, multi-AOI or similar data, grab_image/grab_image_async is not able to provide all the outputs. In all these cases it will simply provide the first image found in the acquired data.
The "extended" grab_data/grab_data_async operators allow to output arbitrary number of HALCON images and also arbitrary number of control data. It is therefore suitable for use in advanced use cases when more than just a single HALCON image should be output. An important use case is acquisition from 3D devices () when the operators can build and output the 3D object model through the control data output. It can be also used in other (possibly even device-specific) situations when the device outputs multiple images for a single acquisition.
The structure of the provided outputs can be queried with help of the 'image_contents', 'data_contents' and related parameters.
The grab_data/grab_data_async can also be used in the simple single-image use cases - in that case they will simply provide a single HALCON image and zero control data outputs. They can thus be used as full replacement of the traditional grab_image/grab_image_async operators.

The HALCON MediaFoundation image acquisition interface has a built-in converter from the pixel formats described in the GenICam Standard Features Naming Convention to the desired HALCON image format. The parameters ColorSpace and BitsPerChannel (open_framegrabber, eventually set_framegrabber_param) define the desired format of the resulting HALCON image. If these parameters are set to defaults, the original pixel format coming from the device is preserved.
To offer a basic support of custom pixel formats (i.e., pixel formats not defined by PFNC or not supported by HALCON), the ColorSpace value 'raw' can be used. In this case the image acquisition interface delivers the buffer to the application without any format conversions.
Note that the same principle is applied whenever a buffer containing other than image data is acquired. Examples of such buffers can be files (e.g., compressed images) or raw data (results of smart camera processing). Such buffers are not real "images", but can still be delivered to the application as 'raw' HALCON images. It is the responsibility of the application to know how to interpret such data.
Last but not least, the 'raw' color space can also be used if the user explicitly wishes to receive raw input data without any conversions. For example when acquiring Bayer encoded images, specifying 'raw' means that the interface should not attempt to decode them to RGB or monochrome format, but deliver the data directly to the application.
It is important to know that when the interface does not have full information about the image format (dimensions and pixel format), it has to choose an artificial one. In such a case it delivers always an 8-bit image with dimensions matching the buffer size (square root of the image size). Eventually an unused tail of the HALCON image (if such an artificial image is bigger than the source buffer) will be padded with zeroes. The fact whether the last acquired buffer contained an image of known properties or a blob of other data (so that the artificial HALCON image size had to be used) as well as the size of the eventual tail padding can be queried using 'image_raw_buffer_type' and 'image_raw_buffer_padding_bytes' parameters.

It is possible to receive notifications about changes of any features exposed through the GenICam interface by the camera and Media Foundation Producer as well as for internal parameters of the acquisition interface.
Note that the notifications might be raised in various circumstances, including:

• The application (you) explicitly changed that feature.
• Another feature has changed and the notified feature "depends" on the changed feature (the dependencies are defined in the GenICam description file).
• Access mode or current range for the feature has changed.
• As a result of regular "polling" in case of uncached features.
• As a result of device event delivery if the feature is connected to that event.
• As a result of new buffer delivery for features corresponding to chunk data.

Note that the notifications are raised whenever the feature is "marked dirty" (its cache invalidated) by one of the actions described above. It does not necessarily mean that its value has really changed, it is up to the application to check this.
Notification callbacks can be registered for individual features using set_framegrabber_callback - see corresponding operator documentation. Additionally, it is possible to use message queues to receive the event notification. In those cases it is necessary to create a message queue and then register the individual feature - see event message queues.

GenICam compatible devices can deliver asynchronous events which optionally carry additional data. It is usually necessary to enable delivery of individual event types using the features 'EventSelector'/'EventNotification' first. For SFNC-compliant events, this is done automatically if the parameter 'event_notification_helper' is enabled.
The decoding of the event data and matching them to the corresponding features, including potential notifications, is performed transparently by the interface.
The actual values might be read through the regular parameter reading mechanism like get_framegrabber_param or by get_message_tuple if you are using message queues to receive events. The choice of the event types to be generated is device-specific. The names of the event related features usually start by convention with a prefix 'Event' (examples might be 'EventFrameTrigger' and 'EventFrameTriggerTimestamp'), however, the device documentation should contain all the information about supported events and their corresponding feature names.
Although the data corresponding to the last delivered event can be in general read at any time, when using callback to receive events it is highly recommended that reading the event data is synchronized to notifications for corresponding event feature(s). Only in such a case it is guaranteed that the read data correspond exactly to the very event instance being notified – and that the feature values are not just being modified through a new instance of the same event. Note that the notifications are raised from context of the event handling/dispatching thread, so when processing the user callback, the event handling mechanism is paused. If multiple data items are associated with the same event, it is enough to register notification just for the actual event feature and read all the data during the callback.
If using message queues to receive events, you can decide to add additional data to be delivered with the corresponding event feature(s), see Event Message Queues. For this case the interface will read all the specified event features as soon as the event is generated and add it to the corresponding message. This guarantees that the delivered information corresponds with the actual value at the time the event was generated.
Besides the asynchronous events generated by the actual device, asynchronous events (optionally including additional data) can be generated by any module of the Media Foundation Producer (system, interface, device and data stream). The information provided above about handling of the device events applies similarly also to the Media Foundation Producer events, including enabling/disabling them (typically using 'EventSelector'/'EventNotification' features provided by given module, i.e. with corresponding module prefix in the feature name). For SFNC-compliant events, this is done automatically if the parameter 'event_notification_helper' is enabled.

This interface supports feature change notifications via message queues. Select the desired target feature with set_framegrabber_param(..., 'event_selector', ...). It is the same plain feature name (GenICam feature or internal parameter) as used with set_framegrabber_param, including a possible prefix, such as '[Device]' (refer to the Parameters – Naming Conventions).
Create a message queue at which you want to receive the notifications with create_message_queue and assign it to the selected feature with set_framegrabber_param(..., 'event_message_queue', QueueHandle).
The message queue can be registered for any GenICam based features, i.e., features published by the device and Media Foundation Producer or for internal features of the acquisition interface. On top of that, the notification can be registered also for internal events occurring within the acquisition interface, in particular 'event_new_buffer' which gets fired whenever the information about last acquired buffer is updated (new buffer grabbed or last buffer info invalidated when restarting the acquisition).
The list of supported targets can be queried by calling get_framegrabber_param(..., 'available_event_names', ...).
One of the important use cases for feature change callbacks is the device event delivery mechanism, see details in Event Data and Feature Change Notifications sections.
A new message would be added to the specified queue whenever a given feature is potentially changed (including its other properties such as range or access mode). Note that it does not necessarily always mean that the feature actually has a new value. A call to set_framegrabber_param(..., 'event_message_queue', 0) unregisters the previously registered message queue from the specified event. Note that the interface keeps just a single registration for every feature, if you attempt to register a new message queue for a feature that already had a message queue registered, the previous registration will be replaced with the new one.
The messages incoming on an event can be retrieved with dequeue_message and will contain at least three tuples. The first tuple (key 'id') is a unique identifier of the acquisition instance the event is coming from. It is a string composed as '<interface>:<unique_name>'. The second tuple (key 'event_name') is the name of the corresponding feature previously specified by 'event_selector'. The third tuple (key 'event_value') contains the value if the corresponding feature if available and readable.
If you decide to add additional data to be delivered with the corresponding event feature(s), add the features of interest with set_framegrabber_param(..., 'event_data', ...). Each event data feature will be appended to the event message with the key being its name and the tuple its value if readable. Note that duplicities possibly specified through 'event_data' are ignored The value of the notified feature itself (already reported in 'event_value') would also be considered as a duplicity and not reported again.

In case of using the HDevelop Image Acquisition Assistant the following hints will help to avoid problems:

• Some parameters depend on special conditions, e.g., a valid buffer or another parameter activated. After opening the camera these conditions may not yet be fulfilled, so the depending parameters are not shown. By using the 'Refresh' button, all parameters are read again and the depending parameters should appear if the conditions are fulfilled then.
• There are also some parameters regarding the image size and the payload size, which can only be changed if no acquisition takes place. The safest way to ensure this is to apply the action parameter 'do_abort_grab'. Please note that 'Update Image' has to be disabled first.
• The behavior of allowing changes to parameters while streaming is active depends on the capabilities of the device. It is possible that some cameras give you control over, e.g., the exposure time, while streaming and others do not.

The HALCON MediaFoundation interface supports an internal color conversion performed in software. The conversion is automatically applied for PFNC (Pixel Format Naming Convention) compatible cameras, when the color format delivered by the camera differs from the user defined format if set via the parameter 'color_space'. The used transformation algorithms are basic and optimized for speed.

Following transformations from the camera color space (see also PFNC) to the interface color space (see also 'color_space' parameter in this document) are supported:

• Bayer pattern to 'rgb':
  

  Bayer_LMMN R G1 G2 B ⇾ [R,G,B] [R,G,B] [R,G,B] [R,G,B]

  Bayer_NMML B G1 G2 R ⇾ [R,G,B] [R,G,B] [R,G,B] [R,G,B]

  with G = (G1 + G2) / 2.

• Y'CbCr to 'rgb' (Note: gamma correction is not considered):
  

  R = Y' + 1.4020 * (Cr- M)
G = Y' - 0.34414 * (Cb- M) -0.71414 * (Cr- M)
B = Y' + 1.7720 * (Cb - M)

• RGB to 'yuv' ('yuv' corresponds to Y'CbCr of PFNC, Note: gamma correction is not considered):
  

  Y' = 0.299 * R + 0.587 * G + 0.114 * B
Cb = -0.16874 * R - 0.33126 * G + 0.5 * B + M
Cr = 0.5 * R - 0.41869 * G - 0.08131 * B + M

• RGB to 'gray':
  

  Y' = 0.299 * R + 0.587 * G + 0.114 * B

with M = 128 for 8 bit raw data, and M = 32768 for 16 bit raw data.
The accuracy of the results is limited due to internal 16.16 fix-point arithmetic for 8 bit ( 0...255), and 24.8 fix-point arithmetic for 16 bit raw data.

Parameter	Value List	Type	Kind	Description
'bits_per_channel'	[-1, 8, 10, 12, 14, 16]	integer	pre-defined	Values for bits per channel.
'camera_type'	['CAMFILE:', 'ini;xml', '<path>', 'default']	string	pre-defined	Syntax for connection configuration file and default value.
'color_space'	['default', 'gray', 'raw', 'rgb', 'rgbx', 'yuv']	string	pre-defined	Values for color space.
'defaults'	[0, 0, 0, 0, 0, 0, 'progressive', -1, 'default', -1.0, 'false', 'default', '0', 0, 0]	mixed	pre-defined	Default values for open_framegrabber.
'device'	[' | device:<device id> | unique_name:<unique name> | interface:<interface id> | producer:Masimov']	string	dynamic	List of discovered devices in the system with information about their device ID, unique name, interface ID and producer. This corresponds to the devices plugged to USB ports on the machine. See the full description in section about device opening.
'external_trigger'	[]			Ignored.
'field'	[]			Unused.
'general'	[]	string	pre-defined	Information about the HALCON MediaFoundation interface.
'generic'	['', 'num_buffers=<num>' ]	string	pre-defined	Value list for the Generic parameter.
'horizontal_resolution'	[]	integer	pre-defined	Used.
'image_height'	[]			Unsupported query.
'image_width'	[]			Unsupported query.
'info_boards'	[' | device:<device_id> | unique_name:<unique_name> | interface:<interface_id> | producer:Masimov | vendor:<vid_xxx> | model:<pid_xxx> | tl_type:Custom | status:<device_status>']	string	dynamic	List of devices discovered in the system. This corresponds to the MediaFoundation compatible devices plugged to USB ports on the machine. device is generated from the friendly name of the device and the device instance path, which will be shown by info_framegrabber(...,'device',...). This is a unique identifier of the connected device for the current system in the current USB port. unique_name is a unique identifier for the device. Its value is the same as the 'device' string. interface shows the unique identifier of the GenTL interface implementation. producer shows the name of the underlying GenICamTL producer. vendor represents the value of the feature 'DeviceVendorName'. model represents the value of the feature 'DeviceModelName'. tl_type shows the type of the underlying transport layer. In this interface the value will always be 'Custom'. status shows, if the device is correctly configured or not. The possible values are 'available', 'read-only', 'busy', and 'unknown'. Even devices that are currently not available for opening are listed.
'parameters'	['<parameters>']	string	pre-defined	Pre-defined parameters of the HALCON interface.
'parameters_readonly'	['<parameters>']	string	pre-defined	Pre-defined read-only parameters of the HALCON interface.
'parameters_writeonly'	['<parameters>']	string	pre-defined	Pre-defined write-only parameters of the HALCON interface.
'port'	[]			Unused.
'revision'	'<revision>'	string	pre-defined	Revision number of the MediaFoundation interface.
'start_column'	[]			Unsupported query.
'start_row'	[]			Unsupported query.
'vertical_resolution'	[]	integer	pre-defined	Used.

Parameters for open_framegrabber