private async Task SetComp(StorageFile backgroundAudio, Dictionary <StorageFile, TimeSpan> imageFiles, CancellationToken cancellationToken) { StorageFile temporaryFile = await CreateFile("Media Composition", "temp (1)", "cmp", cancellationToken); BackgroundAudioTrack backgroundAudioTrack = await BackgroundAudioTrack.CreateFromFileAsync(backgroundAudio); AudioEncodingProperties audioEncodingProperties = backgroundAudioTrack.GetAudioEncodingProperties(); TimeSpan duration = backgroundAudioTrack.OriginalDuration; MediaComposition composition = new MediaComposition(); composition.BackgroundAudioTracks.Add(backgroundAudioTrack); CancelTask(cancellationToken); MediaClip clip; foreach (var item in imageFiles) { CancelTask(cancellationToken); clip = await MediaClip.CreateFromImageFileAsync(item.Key, item.Value); composition.Clips.Add(clip); } composition.CreateDefaultEncodingProfile(); await composition.SaveAsync(temporaryFile); ReportProgress(Stage5, Stage4ProgressBar, TextProgress4, 100); CancelTask(cancellationToken); }