Silverlight 5 beta新特性探索系列:6.Silverlight 5新增低延迟声音效果类SoundEffect.支持wav音乐格式【附带源码实例】...

r囧r小猫 2022-03-28 05:38 154阅读 0赞

在Silverlight 5中新增了一个SoundEffect类和SoundEffectInstance类用以加载wav格式的音乐，这样可以很及时的为动画添加音效。

现在我们看如何使用这两个类来控制播放wav音乐，首先引入mav音乐格式的文件（音频采样大小必须为16或者8位不能是24位，采用PCM编码，22.5, 44.1 or 48khz的采样率）如下图属性：

![2011042016273342.jpg][]

其次将引入的wav格式音乐文件在项目中右键点击其属性设置其“生成操作”为“内容”，如下图所示：

![2011042016275485.jpg][]

现在我们准备XAML代码以控制SoundEffectInstance类的属性，调节音乐播放效果：

< Grid x:Name = " LayoutRoot "  Background = " White " >   
    
 < Slider Height = " 135 "  HorizontalAlignment = " Left "  Margin = " 62,38,0,0 "   
Name = " SlVolume "  VerticalAlignment = " Top "  Width = " 62 "   
Orientation = " Vertical "  Maximum = " 1 "  Value = " 0.5 "  />   
 < Slider Height = " 135 "  HorizontalAlignment = " Left "  Margin = " 162,38,0,0 "   
Name = " SlPitch "  VerticalAlignment = " Top "  Width = " 62 "   
Orientation = " Vertical "  Value = " 0 "  Maximum = " 1 "  Minimum = " \-1 "  />   
 < Slider Height = " 135 "  HorizontalAlignment = " Left "  Margin = " 262,38,0,0 "   
Name = " SlPan "  VerticalAlignment = " Top "  Width = " 62 "   
Orientation = " Vertical "  Value = " 0 "  Maximum = " 1 "  Minimum = " \-1 "  />   
    
 < TextBlock Height = " 23 "  HorizontalAlignment = " Left "  Margin = " 71,179,0,0 "   
Name = " textBlock1 "  Text = " 音量调节 "  VerticalAlignment = " Top "  />   
 < TextBlock Height = " 23 "  HorizontalAlignment = " Left "  Margin = " 166,179,0,0 "   
Name = " textBlock2 "  Text = " 高低音调节 "  VerticalAlignment = " Top "  />   
 < TextBlock Height = " 23 "  HorizontalAlignment = " Left "  Margin = " 271,179,0,0 "   
Name = " textBlock3 "  Text = " 声道平衡 "  VerticalAlignment = " Top "  />   
 </ Grid >

第一步：加载相应的事件

public  MainPage()  
\{  
InitializeComponent();  
 // 第一步：加载相应的事件   
  Loaded  \+=  new  RoutedEventHandler(MainPage\_Loaded);  
 this .SlVolume.ValueChanged \+=   
 new  RoutedPropertyChangedEventHandler < double > (SlVolume\_ValueChanged);  
 this .SlPitch.ValueChanged \+=   
 new  RoutedPropertyChangedEventHandler < double > (SlPitch\_ValueChanged);  
 this .SlPan.ValueChanged \+=   
 new  RoutedPropertyChangedEventHandler < double > (SlPan\_ValueChanged);  
\}

第二步：加载声音WAV文件

第三步：设置声音文件初始化播放属性

void  MainPage\_Loaded( object  sender, RoutedEventArgs e)  
\{  
GetSound();  
\}  
SoundEffect \_soundEffect;  
SoundEffectInstance instance;  
 public  void  GetSound()  
\{  
 // 第二步：加载声音WAV文件   
  var laserStream  =   
Application.GetResourceStream( new  Uri( " zhizu.wav " , UriKind.RelativeOrAbsolute));  
\_soundEffect  =  SoundEffect.FromStream(laserStream.Stream);  
  
 // 第三步：设置声音文件初始化播放属性   
  instance  =  \_soundEffect.CreateInstance();  
  
 // Pitch变调效果属性，是高低音平衡调节，该值在-1到1之间设置   
  instance.Pitch  =  0.0f ;  
  
 // Pan声像调节属性，它用于调节该路声源在空间的分布图像。   
  instance.Pan  =  0.0f ;  
  
 // Volume属性是音量大小调节，该值范围是0-1   
  instance.Volume  =  0.5f ;  
instance.Play();  
\}

第四步：根据Silder控件值的变化动态调节声音属性

private  void  SlVolume\_ValueChanged( object  sender,  
RoutedPropertyChangedEventArgs < double >  e)  
\{  
 // 第四步：调节声音属性   
  instance.Volume  =  float .Parse(e.NewValue.ToString());  
 this .textBlock1.Text  =  " 音量调节 "  \+  e.NewValue.ToString();  
\}  
  
 private  void  SlPitch\_ValueChanged( object  sender,  
RoutedPropertyChangedEventArgs < double >  e)  
\{  
 // 第四步：调节声音属性   
  instance.Pitch  =  float .Parse(e.NewValue.ToString());  
 this .textBlock2.Text  =  " 高低音调节 "  \+  e.NewValue.ToString();  
\}  
  
 private  void  SlPan\_ValueChanged( object  sender,  
RoutedPropertyChangedEventArgs < double >  e)  
\{  
 // 第四步：调节声音属性   
  instance.Pan  =  float .Parse(e.NewValue.ToString());  
 this .textBlock3.Text  =  " 声像调节 "  \+  e.NewValue.ToString();  
\}

注意SoundEffectInstance类的3个音乐效果属性Volume,Pitch,Pan如下：

SoundEffectInstance.Pitch  
 // Pitch变调效果属性，是高低音平衡调节，该值在-1到1之间设置  
 // 当往-1调节时，即往低音调调节  
 // 当往+1调节时，即往高音调调节  
 // 如果是0则正常音高

SoundEffectInstance.Volume  
 // Volume属性是音量大小调节，该值范围是0-1

SoundEffectInstance.Pan  
 // Pan声像调节属性，它用于调节该路声源在空间的分布图像。  
 // 当往-1调节时，相当于把该路声源放在听音的左边。  
 // 当往+1调节时，相当于把该路声源放在听音的右边。  
 // 若把它置于中间位置0时，相当于把该路声源放在听音的正中。  
 // Pan属性是左右声道平衡，该值在-1到1之间设置

最后我们来看运行效果如下图，如果要听试听效果请点击 [SL5SoundEffect.zip][] 下载源码。

![2011042016281138.jpg][]

[2011042016273342.jpg]: /images/20220328/8f1407694d334010a4fbedf45e33afb5.png
[2011042016275485.jpg]: /images/20220328/14f57eec6a7340ee80feb2be26d3ce14.png
[SL5SoundEffect.zip]: http://files.cnblogs.com/chengxingliang/SL5SoundEffect.zip
[2011042016281138.jpg]: /images/20220328/b21750ff43c9497dbcb9dd5accfee05f.png