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RVMedia 7.2 - webcam properties and login dialogs

Posted: Tue Feb 04, 2020 9:30 am
by Sergey Tkachenko
RVMedia 7.2

Trial versions are available at
We decided to abandon trial versions for Lazarus. It looks like, in Lazarus, every unit recompilation makes it incompatible, so only full source code version can be installed in Lazarus reliably.

This update is free for customers who ordered in 2018 and later.

The setups Include a compiled trial code, help, demos.

Main changes:
  • new TRVWebCamDialog component (Windows only)
  • rotation of local cameras
  • changing brightness, contrast, saturation, sharpness and hue of local cameras
  • support for more video modes of local cameras
  • improved http authentication
  • new login dialog
Complete list of changes: ... istory.htm

Previous version: ... f=6&t=9736

Local USB webcams

Posted: Tue Feb 04, 2020 9:38 am
by Sergey Tkachenko
Local USB webcams

All the changes explained in this post are for Windows platform. They are not available in Lazarus for Linux.

Changing properties: dialog

We added a new component: TRVWebCamDialog.
Assign TRVCamera to its Camera property, select a web camera in this TRVCamera component, and call Execute to display a dialog.

webcam-dialog-vpa.png (8.56 KiB) Viewed 32945 times

As you can see, this dialog has two pages. The first page allows changing video processing amplifier properties:
  • brightness
  • contrast
  • hue
  • saturation
  • sharpness
  • gamma
  • color enable (yes/no)
  • white balance
  • backlight compensation
  • gain
The second page allows changing camera control properties:
  • pan, tilt, roll
  • zoom
  • exposure
  • aperture (iris)
  • focus
For some properties, you can choose between automatic and manual mode.
Of course, the camera must support changing these properties, otherwise the dialog displays it disabled.

You can change UI language of this dialog by assigning Language property.

Changing properties: assigning values

TRVCamera.Brightness, Contrast, Saturation, Sharpness, Hue properties now work for local USB webcams too (if the camera supports this property).
Other webcam properties can be accessed in code as well, let me know if you want to know how.


If the camera supports movement (pan and tilt), you can control its movement: Video modes

Since this version, TRVCamera decodes video frames of local cameras itself, not relying on a system conversion to RGB format, as it was before.
As a result, more video modes are supported.
As a second result, now we know exactly which video modes can be decoded, so unsupported video modes are not included to a list of video modes.

HTTP Authentication

Posted: Tue Feb 04, 2020 9:43 am
by Sergey Tkachenko
HTTP Authentication

HTTP authentication code is rewritten. Both basic and digest authentication must work properly now.

A dialog is added to request username and password.

login-dialog.png (14.91 KiB) Viewed 32942 times

This dialog is displayed if login failed, and TRVCamera.LoginPrompt = True (by default, it is False).

You can change UI language of this dialog using TRVCamera.Language property.
Instead of this dialog, you can implement your own user interface to request username and password, using TRVCamera.OnLogin event.

When all attempts to login failed, TRVCamera.OnLoginFailed event occurs.

Other changes in RVMedia 7.2

Posted: Tue Feb 04, 2020 9:47 am
by Sergey Tkachenko

Changes in TRVCamControl component:
  • local webcam support
  • arrows are not highlighted below the mouse pointer if the camera does not support rotation
  • visual improvements (more noticeable in FireMonkey, less in VCL/LCL)
Color Control Properties

As it was said before, TRVCamera.Brightness, Contrast, Saturation, Sharpness, Hue properties now work for local USB webcams too (if the camera supports this property).
Also, we added TRVCamera.GetColorControlPropertyRange method. This method returns minimum, maximum, and default values of the specified property for the selected camera.

RVMedia localization

Posted: Wed Feb 05, 2020 6:31 am
by Sergey Tkachenko
As you can see, since this version, RVMedia includes built-in dialog windows.
So user interface localization become more important.
Currently, RVMedia UI is available in the following languages:
- English,
- French,
- German,
- Russian,
- Spanish,
- Portuguese (Br),
- Chinese (simplified and traditional).

If you want translation to your language, let me know.

RVMedia 7.2.1

Posted: Tue Feb 25, 2020 8:01 pm
by Sergey Tkachenko
RVMedia 7.2.1

A new version of RVMedia is uploaded: v7.2.1.
This is a maintenance release, it fixes several bugs (details can be found in the forum for registered RVMedia users).

RVMedia 7.2.2

Posted: Thu Feb 27, 2020 9:35 pm
by Sergey Tkachenko
RVMedia 7.2.2

One more maintenance release.