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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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

See also

Error and Success Codes

ICameraControl::get_FocalLengths

IVideoProcAmp Interface