Windows Phone 8.1 多媒體（2）：視頻

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原文:Windows Phone 8.1 多媒體（2）：視頻

Windows Phone 8.1 多媒體（1）：相片

Windows Phone 8.1 多媒體（2）：視頻

Windows Phone 8.1 多媒體（3）：音樂

 

 

（1）拍攝視頻

拍攝視頻和拍攝相片的方法是基本一致的：

MediaCapture mediaCapture;MediaEncodingProfile videoEncodingProperties;protected override async void OnNavigatedTo(NavigationEventArgs e){    HardwareButtons.CameraHalfPressed += HardwareButtons_CameraHalfPressed;    HardwareButtons.CameraReleased += HardwareButtons_CameraReleased;    videoCaptrueElement.Source = await Initialize();    await mediaCapture.StartPreviewAsync();}async void HardwareButtons_CameraHalfPressed(object sender, CameraEventArgs e){    if( mediaCapture != null )    {        var video = await KnownFolders.VideosLibrary.CreateFileAsync("video.mp4", CreationCollisionOption.GenerateUniqueName);await mediaCapture.StartRecordToStorageFileAsync(videoEncodingProperties, video);    }}async void HardwareButtons_CameraReleased(object sender, CameraEventArgs e){    if( mediaCapture != null )    {        await mediaCapture.StopRecordAsync();    }}private async Task<MediaCapture> Initialize(){    mediaCapture = new MediaCapture();    await mediaCapture.InitializeAsync();    mediaCapture.VideoDeviceController.PrimaryUse = CaptureUse.Video;    videoEncodingProperties = MediaEncodingProfile.CreateMp4(VideoEncodingQuality.Vga);    return mediaCapture;}protected override void OnNavigatedFrom(NavigationEventArgs e){    if( mediaCapture != null )    {        mediaCapture.Dispose();        mediaCapture = null;    }}

 

（2）編輯視頻

視頻編輯的 API 在 Windows.Media.Editing 命名空間下，具體可看 MSDN：連結

簡單的說就是把某些視頻執行個體化為 MediaClip，然後將這些視頻添加到 MediaComposition.Clips 中去，最後將這些視頻拼接到一起或添加個 BackgroundAudioTrack 什麼的：

MediaClip video = await MediaClip.CreateFromFileAsync(
　　　　　　　　　　　　　　　　await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///thanks.mp4")));MediaComposition videos = new MediaComposition();videos.Clips.Add(video);BackgroundAudioTrack bgm = await BackgroundAudioTrack.CreateFromFileAsync(
　　　　　　　　　　　　　　　　　　　　await StorageFile.GetFileFromApplicationUriAsync(new Uri("Above Your Hand.mp3")));videos.BackgroundAudioTracks.Clear();videos.BackgroundAudioTracks.Add(bgm);await videos.SaveAsync(await ApplicationData.Current.LocalFolder.CreateFileAsync("video.mp4", CreationCollisionOption.ReplaceExisting));

 

（3）錄製手機螢幕視頻

錄製手機螢幕視頻是 WP8.1 新加的 API，使用方法和拍攝視頻差不多，只需將錄製對象設為螢幕即可：

var screenCapture = ScreenCapture.GetForCurrentView();mediaCapture = new MediaCapture();await mediaCapture.InitializeAsync(new MediaCaptureInitializationSettings{    VideoSource = screenCapture.VideoSource,    AudioSource = screenCapture.AudioSource,});var file = await KnownFolders.VideosLibrary.CreateFileAsync("screenrecording.mp4", CreationCollisionOption.ReplaceExisting);await mediaCapture.StartRecordToStorageFileAsync(MediaEncodingProfile.CreateMp4(VideoEncodingQuality.Auto), file);

停止錄製：

if( mediaCapture != null ){    await mediaCapture.StopRecordAsync();    mediaCapture.Dispose();    mediaCapture = null;}