InvalidOperationException
   在 System.Diagnostics.Process.GetProcessHandle(Int32 access, Boolean throwIfExited)
   在 System.Diagnostics.Process.Kill()
   在 DynamicClass.Form1.<>c__DisplayClass6.<h264_fun>b__4(Object sender, EventArgs e)
   在 System.EventHandler.Invoke(Object sender, EventArgs e)
   在 System.Diagnostics.Process.OnExited()
   在 System.Diagnostics.Process.RaiseOnExited()
   在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   在 System.Threading._ThreadPoolWaitOrTimerCallback.PerformWaitOrTimerCallback(Object state, Boolean timedOut)