KSPROPERTY_CAMERACONTROL_EXTENDED_OPTIMIZATIONHINT (application performance strategy)
Camera drivers may optimize their capture operation based on hints provided by the application. This property informs the driver to set its performance strategy based on what operation is likely used the most. For example, when optimized for photo, the camera driver may program the sensor to optimize sensor exposure speed and resolution for lower latency from photo capture trigger to image capture. Similarly, when optimized for video, the camera driver may program the sensor for higher frame rate but at a lower resolution.
Usage summary table
| Get | Set | Target | Property descriptor type | Property value type |
|---|---|---|---|---|
| Yes | Yes | Filter | KSPROPERTY | KSCAMERA_EXTENDEDPROP_HEADER |
The property value (operation data) contains a KSCAMERA_EXTENDEDPROP_HEADER structure and a KSCAMERA_EXTENDEDPROP_VALUE structure.
The total property data size is sizeof(KSCAMERA_EXTENDEDPROP_HEADER) + sizeof(KSCAMERA_EXTENDEDPROP_VALUE). The Size member of KSCAMERA_EXTENDEDPROP_HEADER is set to this total property data size.
The Capability member of KSCAMERA_EXTENDEDPROP_HEADER contains a bitwise OR combination of one or more of the following optimization hints.
| Optimization hint | Description |
|---|---|
| KSCAMERA_EXTENDEDPROP_OPTIMIZATION_PHOTO | Camera operation is optimized for photos |
| KSCAMERA_EXTENDEDPROP_OPTIMIZATION_VIDEO | Camera operation is optimized for video |
The Flags member of KSCAMERA_EXTENDEDPROP_HEADER contains the optimization currently set for the camera (one value).
The default optimization type is KSCAMERA_EXTENDEDPROP_OPTIMIZATION_PHOTO. If this property is supported by the camera driver, then both optimization types must be supported.
This property control is synchronous and not cancelable.
Remarks
Optimization modes
KSCAMERA_EXTENDEDPROP_OPTIMIZATION_PHOTO
All camera drivers must be in this mode until explicitly informed to use the KSCAMERA_EXTENDEDPROP_OPTIMIZATION_VIDEO mode. The purpose of this mode is to optimize the camera hardware for photo operations. Video operations must still be functional in this mode.
KSCAMERA_EXTENDEDPROP_OPTIMIZATION_VIDEO
This mode indicates that the camera will likely be used for video operations. The camera driver should optimize the hardware for video operations for this mode. Photo operations must be functional, but there resource usage priority is for video operations.
Getting the property
When responding to a KSPROPERTY_TYPE_GET request, the driver sets the members of the KSCAMERA_EXTENDEDPROP_HEADER to the following.
| Member | Value |
|---|---|
| Version | 1 |
| PinId | KSCAMERA_EXTENDEDPROP_FILTERSCOPE (0xFFFFFFFF) |
| Size | sizeof(KSCAMERA_EXTENDEDPROP_HEADER) + sizeof(KSCAMERA_EXTENDEDPROP_VALUE) |
| Result | 0 |
| Capability | Optimization values supported |
| Flags | The current optimization value setting |
If no optimization mode was previously set, then the driver sets Flags to KSCAMERA_EXTENDEDPROP_OPTIMIZATION_PHOTO (default).
Setting the property
When the property is set, a KSPROPERTY_TYPE_SET request, the Flags member of KSCAMERA_EXTENDEDPROP_HEADER will contain the optimization mode to set.
Requirements
Version: Available starting with Windows 8.1
Header: Ksmedia.h (include Ksmedia.h)