mvIMPACT Acquire SDK C++
SystemV4L2 Class Reference

A class containing mvV4L2 specific settings to control the overall behaviour of the driver(Device specific interface layout only). More...

Inheritance diagram for SystemV4L2:
SystemSettings ComponentCollection

Public Member Functions

HOBJ hObj (void) const
 Returns a unique identifier for the component collection referenced by this object. More...
 
const ComponentCollectionrestoreDefault (void) const
 Restores the default for every component of this collection. More...
 
 SystemV4L2 (Device *pDev)
 Constructs a new mvIMPACT::acquire::SystemV4L2 object. More...
 

Public Attributes

PropertyI acquisitionIdleTimeMax_ms
 An integer property defining the maximum time in ms the driver waits for new requests being queued until streaming by the device will automatically be stopped. More...
 
PropertyIAcquisitionMode acquisitionMode
 An enumerated integer property defining the acquisition mode of the device. More...
 
PropertyI balance
 If V4L2 device supports audio, this integer property adjusts the audio balance. More...
 
PropertyI bass
 If V4L2 device supports audio, this integer property adjusts the audio bass. More...
 
PropertyIBoolean featurePollingEnable
 An enumerated integer property defining whether features defining a polling time shall be updated automatically or not. More...
 
PropertyI featurePollingInterval_ms
 An integer property defining the polling interval in ms the driver waits for each iteration before running through update loop again. More...
 
PropertyI imageProcessingMaximumThreadCount
 An integer property influencing the number of parallel threads used by the internal image processing pipeline. More...
 
PropertyIImageProcessingMode imageProcessingMode
 An enumerated integer property influencing the behaviour of the internal image processing pipeline. More...
 
PropertyIImageProcessingOptimization imageProcessingOptimization
 An enumerated integer property influencing the behaviour of the internal image processing algorithms. More...
 
PropertyIBoolean loudness
 If V4L2 device supports audio, this enumerated integer property sets audio loudness on/off. More...
 
PropertyI methodPollingInterval_ms
 An integer property defining the polling interval in ms the driver waits during each iteration before checking a methods execution state again. More...
 
PropertyI methodPollingMaxRetryCount
 An integer property defining the polling interval in ms the driver waits during each iteration before checking a methods execution state again. More...
 
PropertyIBoolean mute
 If V4L2 device supports audio, this enumerated integer property sets audio mute on/off. More...
 
PropertyI requestCount
 An integer property defining the number of requests allocated by the driver. More...
 
PropertyI treble
 If V4L2 device supports audio, this integer property adjusts the audio treble. More...
 
PropertyI volume
 If V4L2 device supports audio, this integer property adjusts the audio volume. More...
 

Protected Attributes

HOBJ m_hRoot
 

Detailed Description

A class containing mvV4L2 specific settings to control the overall behaviour of the driver(Device specific interface layout only).

Note
UNDER CONSTRUCTION! Subject to change.
This class will only be available if mvIMPACT::acquire::Device::interfaceLayout is set to mvIMPACT::acquire::dilDeviceSpecific before the device is opened.

Constructor & Destructor Documentation

◆ SystemV4L2()

SystemV4L2 ( Device pDev)
inlineexplicit

Constructs a new mvIMPACT::acquire::SystemV4L2 object.

Parameters
[in]pDevA pointer to a mvIMPACT::acquire::Device object obtained from a mvIMPACT::acquire::DeviceManager object.

Member Function Documentation

◆ hObj()

HOBJ hObj ( void  ) const
inlineinherited

Returns a unique identifier for the component collection referenced by this object.

This handle will always reference an object of type mvIMPACT::acquire::ComponentList.

Returns
A unique identifier for the component referenced by this object.

◆ restoreDefault()

const ComponentCollection& restoreDefault ( void  ) const
inlineinherited

Restores the default for every component of this collection.

Calling this function will restore the default value for every component belonging to this collection.

Note
The caller must have the right to modify the component. Otherwise an exception will be thrown.
Returns
A const reference to the component.

Member Data Documentation

◆ acquisitionIdleTimeMax_ms

PropertyI acquisitionIdleTimeMax_ms
inherited

An integer property defining the maximum time in ms the driver waits for new requests being queued until streaming by the device will automatically be stopped.

This property defines the maximum time in milliseconds the driver waits for new mvIMPACT::acquire::Request objects being queued by calling mvIMPACT::acquire::FunctionInterface::imageRequestSingle once the driver will automatically send an acquisition stop command to a streaming device (such as a GigE Vision or USB3 Vision device) when the driver's request queue has run empty (thus the driver has no more buffers to capture data into).

This property will only be taken into account when mvIMPACT::acquire::Device::acquisitionStartStopBehaviour has been set to mvIMPACT::acquire::assbDefault.

Note
This property will not be available for every device. Right now only devices operated through the GenTL driver package will support this feature.
Since
2.4.1

◆ acquisitionMode

PropertyIAcquisitionMode acquisitionMode
inherited

An enumerated integer property defining the acquisition mode of the device.

Valid values for this property are defined by the enumeration mvIMPACT::acquire::TAcquisitionMode.

◆ balance

PropertyI balance

If V4L2 device supports audio, this integer property adjusts the audio balance.

This property represents a V4L2-audio-control ID.

Note
This property is not supported by every device. Therefore always call the function mvIMPACT::acquire::Component::isValid to check if this property is available or not. If supported, a minimum value, a maximum value and step width will be defined. Thus, invalid values may be tuned after writing to fit within the step size, values too large or too small will raise an exception.

◆ bass

PropertyI bass

If V4L2 device supports audio, this integer property adjusts the audio bass.

This property represents a V4L2-audio-control ID.

Note
This property is not supported by every device. Therefore always call the function mvIMPACT::acquire::Component::isValid to check if this property is available or not. If supported, a minimum value, a maximum value and step width will be defined. Thus, invalid values may be tuned after writing to fit within the step size, values too large or too small will raise an exception.

◆ featurePollingEnable

PropertyIBoolean featurePollingEnable
inherited

An enumerated integer property defining whether features defining a polling time shall be updated automatically or not.

Valid values for this property are defined by the enumeration mvIMPACT::acquire::TBoolean.

See also
mvIMPACT::acquire::SystemSettings::featurePollingInterval_ms

◆ featurePollingInterval_ms

PropertyI featurePollingInterval_ms
inherited

An integer property defining the polling interval in ms the driver waits for each iteration before running through update loop again.

Some features define a so called polling time. This is a recommendation by the device/driver stating that this property might change it's value without user interaction act a certain rate (e.g. the device temperature could be one example for a feature with such a behaviour). When mvIMPACT::acquire::SystemSettings::featurePollingEnable is set to mvIMPACT::acquire::bTrue a thread will check every featurePollingInterval_ms if features need to be updated. This will only cause communication with a device for each feature who's polling time has elapsed.

Note
This property will not be available for every device. Right now only devices operated through the GenTL driver package will support this feature.
Since
2.18.3

◆ imageProcessingMaximumThreadCount

PropertyI imageProcessingMaximumThreadCount
inherited

An integer property influencing the number of parallel threads used by the internal image processing pipeline.

This property can be used to control the size of the internal thread pool used for image processing tasks. Using a value higher than the number of physical CPU cores usually has a negative impact on the performance. Use with care!

Note
This property will only be available on some platforms. Always check if this property is available before using it!
See also
mvIMPACT::acquire::SystemSettings::imageProcessingOptimization
mvIMPACT::acquire::SystemSettings::imageProcessingMode
Multithreading
Since
2.41.0

◆ imageProcessingMode

PropertyIImageProcessingMode imageProcessingMode
inherited

An enumerated integer property influencing the behaviour of the internal image processing pipeline.

Valid values for this property are defined by the enumeration mvIMPACT::acquire::TImageProcessingMode.

Note
This property will only be available if mvIMPACT::acquire::Device::userControlledImageProcessingEnable has been set to mvIMPACT::acquire::bTrue before the device is opened.
See also
mvIMPACT::acquire::Device::userControlledImageProcessingEnable
mvIMPACT::acquire::Request::hasProcessingBeenSkipped
Since
2.14.0

◆ imageProcessingOptimization

PropertyIImageProcessingOptimization imageProcessingOptimization
inherited

An enumerated integer property influencing the behaviour of the internal image processing algorithms.

Valid values for this property are defined by the enumeration mvIMPACT::acquire::TImageProcessingOptimization.

Since
2.12.2

◆ loudness

PropertyIBoolean loudness

If V4L2 device supports audio, this enumerated integer property sets audio loudness on/off.

This property represents a boolean-valued V4L2-control ID. Valid values for this property are defined by the enumeration mvIMPACT::acquire::TBoolean.

Note
This property is not supported by every device. Therefore always call the function mvIMPACT::acquire::Component::isValid to check if this property is available or not.

◆ m_hRoot

HOBJ m_hRoot
protectedinherited

◆ methodPollingInterval_ms

PropertyI methodPollingInterval_ms
inherited

An integer property defining the polling interval in ms the driver waits during each iteration before checking a methods execution state again.

When working with a GenICam compliant device, GenICam method objects need to be checked for their completion status every now and then. This parameter defines how often this shall be done.

Note
This property will not be available for every device. Right now only devices operated through the GenTL driver package will support this feature.
Since
2.18.3

◆ methodPollingMaxRetryCount

PropertyI methodPollingMaxRetryCount
inherited

An integer property defining the polling interval in ms the driver waits during each iteration before checking a methods execution state again.

When working with a GenICam compliant device, GenICam method objects need to be checked for their completion status every now and then. This parameter defines how often this shall be done at all. A method is checked for completion methodPollingMaxRetryCount * methodPollingInterval_ms at max. Until then either the device starts to inform the driver that it needs more time OR the execution of the method has completed successfully or an error will be generated.

Note
This property will not be available for every device. Right now only devices operated through the GenTL driver package will support this feature.
Since
2.18.3

◆ mute

If V4L2 device supports audio, this enumerated integer property sets audio mute on/off.

This property represents a boolean-valued V4L2-control ID. Valid values for this property are defined by the enumeration mvIMPACT::acquire::TBoolean.

Note
This property is not supported by every device. Therefore always call the function mvIMPACT::acquire::Component::isValid to check if this property is available or not.

◆ requestCount

PropertyI requestCount
inherited

An integer property defining the number of requests allocated by the driver.

Each request object can be used to capture data into. Multiple requests can be processed by a device driver as background tasks.

Setting this property to a value at least allowing a driver to capture data for up to 500ms without user interaction (thus 0.5 times the expected frame rate) is highly recommended. Increasing this value will NOT introduce additional latency to your application. The only drawback will be additional RAM consumption by the driver but applications that do not need to copy the request buffers can even benefit from that as the overall memory fragmentation is likely to go down then. Values smaller than 3 most likely result in undesired behaviour and should be avoided unless absolutely needed.

Note
For performance reasons this value can be increased at any time(only exception: Working with the interface layout mvIMPACT::acquire::dilGenICam while streaming is active) but can only be decreased when no request object is currently locked by the application and no requests has been queued for acquisition. So modifying this value might require the application to call mvIMPACT::acquire::FunctionInterface::imageRequestReset and several calls to mvIMPACT::acquire::Request::unlock before.

There are not too many reasons to modify the default request count suggested by the device driver. Good reasons include:

  • a single image is huge compared to the overall system memory(e.g. a single image has 200MB while the system itself only has about 2GB of RAM. Here it might make sense to reduce the number of capture buffers to 1 or 2. Please note that in such a scenario double buffering or live display when one buffer is constantly blocked by the display engine can become a challenge!
  • the frame rate is high(larger than 100 frames per second) and no frames shall be lost. Here it might make sense to set the number of capture buffers to something like frame rate divided by 2 to 5 as a rule of thumb.
See also
mvIMPACT::acquire::FunctionInterface::requestCount

◆ treble

PropertyI treble

If V4L2 device supports audio, this integer property adjusts the audio treble.

This property represents a V4L2-audio-control ID.

Note
This property is not supported by every device. Therefore always call the function mvIMPACT::acquire::Component::isValid to check if this property is available or not. If supported, a minimum value, a maximum value and step width will be defined. Thus, invalid values may be tuned after writing to fit within the step size, values too large or too small will raise an exception.

◆ volume

PropertyI volume

If V4L2 device supports audio, this integer property adjusts the audio volume.

This property represents a V4L2-audio-control ID.

Note
This property is not supported by every device. Therefore always call the function mvIMPACT::acquire::Component::isValid to check if this property is available or not. If supported, a minimum value, a maximum value and step width will be defined. Thus, invalid values may be tuned after writing to fit within the step size, values too large or too small will raise an exception.

The documentation for this class was generated from the following file: