背景
一款广告播放器的需求：可以循环播放多个视频当每个视频播完后立即播放下一个，中间不得有黑屏过程。
##第一版方案
申明一个MediaElement 当每个视频播放完成后（MediaEnded）事件中指定下一个视频地址 这边就不贴出代码了
结果：每个视频交替时会有长时间空白期原因：1.设置MediaElement.source后视频缓冲需要时间（VlC就没有这问题 但是VLC在wpf下只能离屏渲染播放炒鸡卡 故放弃）。2.设置soucre后调用play()会出现不发调用成功的情况（应该正在缓冲加载，这个时候调用play()失效）。
放弃第一方案
第二方案
声明多个MediaElement每个初始化时设置source，当播放摸个视频时，显示对应的MediaElement并调用play()，否则隐藏并pause(); 结果：程序打开时开的要命，内存飙升。多个视频同时缓冲 崩溃。。。。 方案优化：
/// <summary>
/// MainWindow3.xaml 的交互逻辑
/// </summary>
public partial class MainWindow3 : Window
{
public MainWindow3()
{
InitializeComponent();
}
public int currentindex = 0;
public List<string> datalist = new List<string>() { AppDomain.CurrentDomain.BaseDirectory + "1.mp4", AppDomain.CurrentDomain.BaseDirectory + "2.mp4", AppDomain.CurrentDomain.BaseDirectory + "3.mp4", AppDomain.CurrentDomain.BaseDirectory + "4.mp4" };
private void Window_Loaded(object sender, RoutedEventArgs e)
{
MediaElement media1 = new MediaElement();
//media1.Clock.CurrentProgress.
media1.LoadedBehavior = MediaState.Manual;
media1.UnloadedBehavior = MediaState.Stop;
media1.Source = new Uri(AppDomain.CurrentDomain.BaseDirectory + "1.mp4", UriKind.Absolute);
media1.MediaFailed += MediaFailed;
media1.MediaEnded += MediaEnded;
media1.Width = 400;
media1.Height = 300;
media1.Visibility = Visibility.Hidden;
MediaElement media2 = new MediaElement();
//media1.Clock.CurrentProgress.
media2.LoadedBehavior = MediaState.Manual;
media2.UnloadedBehavior = MediaState.Stop;
//media2.Source = new Uri(AppDomain.CurrentDomain.BaseDirectory + "3.mp4", UriKind.Absolute);
media2.MediaFailed += MediaFailed;
media2.MediaEnded += MediaEnded;
media2.Width = 400;
media2.Height = 300;
media2.Visibility = Visibility.Hidden;
MediaElement media3 = new MediaElement();
//media1.Clock.CurrentProgress.
media3.LoadedBehavior = MediaState.Manual;
media3.UnloadedBehavior = MediaState.Stop;
//media2.Source = new Uri(AppDomain.CurrentDomain.BaseDirectory + "3.mp4", UriKind.Absolute);
media3.MediaFailed += MediaFailed;
media3.MediaEnded += MediaEnded;
media3.Width = 400;
media3.Height = 300;
media3.Visibility = Visibility.Hidden;
MediaElement media4 = new MediaElement();
//media1.Clock.CurrentProgress.
media4.LoadedBehavior = MediaState.Manual;
media4.UnloadedBehavior = MediaState.Stop;
//media2.Source = new Uri(AppDomain.CurrentDomain.BaseDirectory + "3.mp4", UriKind.Absolute);
media4.MediaFailed += MediaFailed;
media4.MediaEnded += MediaEnded;
media4.Width = 400;
media4.Height = 300;
media4.Visibility = Visibility.Hidden;
this.maincanvas.Children.Add(media1);
this.maincanvas.Children.Add(media2);
this.maincanvas.Children.Add(media3);
this.maincanvas.Children.Add(media4);
}
public async void StartPlayResource()
{
await Task.Factory.StartNew(() =>
{
double endtime = 10;
Dispatcher.Invoke(delegate
{
MediaElement v = this.maincanvas.Children[currentindex] as MediaElement;
v.Visibility = Visibility.Visible;
if (v.NaturalDuration.HasTimeSpan)
{
endtime = v.NaturalDuration.TimeSpan.TotalSeconds;
}
v.Stop();
v.Play();
});
LoadNextSource(endtime);
});
}
private void LoadNextSource(double seconds)
{
Task.Factory.StartNew(() =>
{
int delaytime = 10;
if (seconds > 3)
{
delaytime = (int)(seconds - 3);
}
else
{
delaytime = 2;
}
Thread.Sleep(delaytime * 1000);
Dispatcher.Invoke(delegate
{
if (currentindex < datalist.Count - 1)
{
MediaElement media = this.maincanvas.Children[currentindex + 1] as MediaElement;
if (media.Source == null)
{
media.Source = new Uri(datalist[currentindex + 1]);
}
}
});
});
}
private void MediaFailed(object sender, ExceptionRoutedEventArgs e)
{
try
{
MessageBox.Show("报错");
}
catch (Exception ex)
{
}
}
private void MediaEnded(object sender, RoutedEventArgs e)
{
try
{
UIElement uiitem = sender as UIElement;
uiitem.Visibility = Visibility.Hidden;
if (currentindex == datalist.Count - 1)
{
currentindex = 0;
}
else
{
currentindex++;
}
StartPlayResource();
}
catch (Exception ex)
{
}
}
private void Button_Click(object sender, RoutedEventArgs e)
{
try
{
currentindex = 0;
StartPlayResource();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
初始化的时候第一个视频赋值source 每个视频快结束是单独线程加载下一个视屏。
测试结果:播放没有问题，程序打开流畅。 其实可以在每个时候播放完成后释放资源，不然视频多了仍然会内存爆棚。
这边有一个很大的坑 在AMD独显机器上会爆硬件错误，随后只要运行视频程序（如QQ影音 迅雷影音 mediaplayer）播放视屏就会死机 至少AMD的R系列是这样。查了所有资料，仍然说不清是显卡问题还是解码器问题，但本人觉得是AMD显卡问题，而且不同版本的显卡驱动下表现得状态不一样
最后感谢德熙帮我解决AMD显卡问题，方案是使用了他们厂封装的DirectShowLib-2005的WPF控件替代了MediaElement