c# - VideoTransformEffectDefinition 以错误结尾：无法解码视频

Question

我正在尝试使用VideoTransformEffectDefinition。

        var clip = await MediaClip.CreateFromFileAsync(pickedFile);//creating clip from storage file
        MediaComposition composition = new MediaComposition();
        composition.Clips.Add(clip);
        VideoTransformEffectDefinition videoEffect1 = new VideoTransformEffectDefinition();
        videoEffect1.PaddingColor = Colors.Blue;//this line is not necessary, does not matter how videoEffect is changed 
        clip.VideoEffectDefinitions.Add(videoEffect1);//adding videoEffect
        this.mediaElement.SetMediaStreamSource(composition.GenerateMediaStreamSource());//setting source to MediaElement

这不会抛出异常，但它告诉我

“错误：视频无法解码”

关于媒体元素。

这很奇怪，因为代码与VideoStabilizationEffectDefinition配合得很好：

        var clip = await MediaClip.CreateFromFileAsync(pickedFile);//creating clip from storage file
        MediaComposition composition = new MediaComposition();
        composition.Clips.Add(clip);
        VideoStabilizationEffectDefinition videoEffect = new VideoStabilizationEffectDefinition();
        clip.VideoEffectDefinitions.Add(videoEffect);//adding videoEffect
        this.mediaElement.SetMediaStreamSource(composition.GenerateMediaStreamSource());//setting source to MediaElement

我究竟做错了什么？

Answer 1

VideoTransformEffectDefinition唯一适用于MediaTranscoder. 它没有任何效果MediaComposition。MediaElement当您设置by时，它会抛出 NullReferenceException MediaElement.SetMediaStreamSource(MediaComposition .GenerateMediaStreamSource())。

GitHub提供了一个使用MediaTranscoder. 在 Scenario1 中，它创建了MediaTranscoderbyprivate MediaTranscoder _Transcoder = new MediaTranscoder();您可以将 by添加VideoTransformEffectDefinition到。MediaTranscoderAddAudioEffect(System.String activatableClassId, System.Boolean effectRequired, IPropertySet configuration)

您可以将以下代码添加到TranscodePresetScenario1_Default.xaml.cs 中的事件。

例如：

VideoTransformEffectDefinition videoEffect = new VideoTransformEffectDefinition();
_Transcoder.ClearEffects();
var activatableClassId = videoEffect.ActivatableClassId;
_Transcoder.AddVideoEffect(activatableClassId, true, videoEffect.Properties);
videoEffect.PaddingColor = Colors.Blue;
videoEffect.Rotation = MediaRotation.Clockwise90Degrees;