IVideoProcAmp::get_DigitalMultiplier method (vidcap.h)
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The get_DigitalMultiplier method returns the camera's digital zoom level.
Syntax
HRESULT get_DigitalMultiplier(
[out] long *pValue,
[out] long *pFlags
);
Parameters
[out] pValue
Receives the digital zoom multiplier.
[out] pFlags
Receives one or more flags. See VideoProcAmpFlags.
Return value
Returns an HRESULT value.
Remarks
Digital zoom is applied after the image is captured. The effect of digital zoom is to multiply the optical magnification by a factor m, which can be calculated as follows:
m = ( (Z'cur - Z'min) * (m-max - 1) ) / (Z'max - Z'min) ) + 1
where
- Z'cur = Current digital zoom level.
- Z'min, Z'max = Minimum and maximum digital zoom. See IVideoProcAmp::getRange_DigitalMultiplier.
- m-max = Maximum digital magnification. See KSPROPERTY_VIDEOPROCAMP_DIGITAL_MULTIPLIER_LIMIT, documented in the Windows DDK.
Requirements
| Minimum supported client | Windows XP with SP2 [desktop apps only] |
| Minimum supported server | Windows Server 2003 R2 [desktop apps only] |
| Target Platform | Windows |
| Header | vidcap.h |