Why does using VideoTransformEffectDefinition affect the camera brightness

LXY 20

I'm using VideoTransformEffectDefinition to rotate the camera VideoPreviewWhy does using VideoTransformEffectDefinition reduce the brightness?How can this problem be avoided?

LXY 20 Reputation points

2025-01-09T12:52:06.74+00:00

I don't want to use SetPreviewRotation because I also need to use VideoTransformEffectDefinition‘s mirror and crop.
Junjie Zhu - MSFT 20,191 Reputation points Microsoft Vendor

2025-01-10T02:59:01.45+00:00

Hello @LXY ,

Welcome to Microsoft Q&A!

How do you add VideoTransformEffectDefinition to MediaCapture? Could you please provide a minimal-reproducible-example to help us further check the problem for you?

Thank you.

LXY 20

MainPage.xaml

<Page
    x:Class="App1.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App1"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <StackPanel Loaded="StackPanel_Loaded" Orientation="Horizontal">
        <StackPanel>
            <Button Content="AddEffect" x:Name="AddEffectButton"           Click="AddEffectButton_Click"/>
            <Button Content="ClearEffects" x:Name="ClearEffectsButton" Click="ClearEffectsButton_Click"/>
            <TextBlock x:Name="StateBlock"/>
        </StackPanel>
        <CaptureElement x:Name="CameraElement" Width="600" Height="400"/>
    </StackPanel>
</Page>

MainPage.xaml.cs

MediaCapture mediaCapture;
Windows.Media.Effects.VideoTransformEffectDefinition VideoEffect;
private async void StackPanel_Loaded(object sender, RoutedEventArgs e) {
      VideoEffect = new Windows.Media.Effects.VideoTransformEffectDefinition();
      mediaCapture = new MediaCapture();
      await mediaCapture.InitializeAsync();
      CameraElement.Source = mediaCapture;
      await mediaCapture.StartPreviewAsync();
 }
private void AddEffectButton_Click(object sender, RoutedEventArgs e) {
	  VideoEffect.Rotation= Windows.Media.MediaProperties.MediaRotation.None;
      _ = mediaCapture.AddVideoEffectAsync(VideoEffect, MediaStreamType.VideoPreview);
      StateBlock.Text += "AddEffect" + Environment.NewLine;
}
private void ClearEffectsButton_Click(object sender, RoutedEventArgs e) {
       _=mediaCapture.ClearEffectsAsync(MediaStreamType.VideoPreview);
       StateBlock.Text += "ClearEffects" + Environment.NewLine;
}

Practical results：

App1s

Junjie Zhu - MSFT 20,191 Reputation points Microsoft Vendor

2025-01-10T09:44:05.24+00:00

Hello @LXY ,

I tested your code on Surface, the camera brightness did not change.

Can this behavior be reproduced on other devices or other cameras?

Thank you.
Roy Li - MSFT 33,596 Reputation points Microsoft Vendor

2025-01-31T01:58:58.08+00:00

Hope you've been well. Any updates about this issue?

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Why does using VideoTransformEffectDefinition affect the camera brightness

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