Implementing Hardware Video Adjustments in Delphi Applications¶

Overview¶

Modern video capture devices offer powerful hardware-level adjustments that can significantly enhance the quality of your video applications. By leveraging these capabilities in your Delphi applications, you can provide users with professional-grade video control features without complex software-based image processing.

Supported Adjustment Types¶

Most webcams and video capture devices support several adjustment parameters:

Brightness
Contrast
Saturation
Hue
Sharpness
Gamma
White balance
Gain

Retrieving Available Adjustment Ranges¶

Before setting adjustments, you'll need to determine what ranges are supported by the connected device. The Video_CaptureDevice_VideoAdjust_GetRanges method provides this information.

Delphi Implementation¶

// Retrieve the available range for brightness adjustment
// Returns minimum, maximum, step size, default value, and auto-adjustment capability
VideoCapture1.Video_CaptureDevice_VideoAdjust_GetRanges(adj_Brightness, min, max, step, default, auto);

C++ MFC Implementation¶

// C++ MFC implementation for getting brightness adjustment ranges
// Store results in integer variables for UI configuration
int min, max, step, default_value;
BOOL auto_value;
m_VideoCapture.Video_CaptureDevice_VideoAdjust_GetRanges(
  VF_VIDEOCAP_ADJ_BRIGHTNESS,
  &min,
  &max,
  &step,
  &default_value,
  &auto_value);

VB6 Implementation¶

' VB6 implementation for retrieving brightness adjustment parameters
' Use these values to configure slider controls and checkboxes
Dim min As Integer, max As Integer, step As Integer, default_val As Integer
Dim auto_val As Boolean
VideoCapture1.Video_CaptureDevice_VideoAdjust_GetRanges adj_Brightness, min, max, step, default_val, auto_val

Setting Adjustment Values¶

Once you've determined the available ranges, you can use the Video_CaptureDevice_VideoAdjust_SetValue method to apply specific settings to the video stream.

Delphi Implementation¶

// Set the brightness level based on trackbar position
// The third parameter enables/disables automatic brightness adjustment
VideoCapture1.Video_CaptureDevice_VideoAdjust_SetValue(
  adj_Brightness, 
  tbAdjBrightness.Position,
  cbAdjBrightnessAuto.Checked);

C++ MFC Implementation¶

// C++ MFC implementation for setting brightness value
// Uses slider position for manual adjustment value
// Checkbox state determines if auto-adjustment is enabled
m_VideoCapture.Video_CaptureDevice_VideoAdjust_SetValue(
  VF_VIDEOCAP_ADJ_BRIGHTNESS,
  m_sliderBrightness.GetPos(),
  m_checkBrightnessAuto.GetCheck() == BST_CHECKED);

VB6 Implementation¶

' VB6 implementation for applying brightness settings
' Uses trackbar value for adjustment level
' Checkbox value determines automatic adjustment mode
VideoCapture1.Video_CaptureDevice_VideoAdjust_SetValue _
  adj_Brightness, _
  tbAdjBrightness.Value, _
  cbAdjBrightnessAuto.Value = vbChecked

Best Practices for Video Adjustment Implementation¶

When implementing video adjustments in your applications:

Always check device capabilities first, as not all devices support all adjustment types
Provide intuitive UI controls like sliders with appropriate min/max values
Include auto-adjustment options when available
Consider saving user preferences for future sessions
Implement real-time preview so users can see the effects of their adjustments

Additional Resources¶

Please contact our support team for assistance with implementing these features in your application. Visit our GitHub repository for additional code samples and implementation examples.