DirectX 9 Audio/Video Playback object memory question

[Guest Deleted member 22320]

I've got an app that imports the DirectX 9's Microsoft.DirectX.AudioVideoPlayback namespace for access to the Audio and Video objects. I have 2 private fields, AP, and VP (for audio and video playback). When i start playback of a new file I would have to create a new playback object for that flie, so I would just set the old AP/VP field = nothing and then set it to a new a/v object. I noticed that as the files played and went to the next track the memory usage of my app would forever increase with each passing track. Looking into matters i decieded to put a .Dispose on the previous reference right before setting a new one.

 

And this worked fine if i keep sending this class a new filename via Play(Filename) I can go all day giving it songs to play, but for some unknown reason if I let it trigger the end of song event and let it progress to the next song on its own, I get an error, but while the error shows, the next song continues to play perfectly until i end debugging.

 

Error:

An unhandled exception of type 'System.NullReferenceException' occurred in microsoft.directx.audiovideoplayback.dll

Additional information: Object reference not set to an instance of an object.

 

And it breaks on a line in which i guess is in the actual AP or VP object.

 

Disassembly:

0000012a mov      eax,dword ptr [eax+20h]

 

 

Heres a snippet of how my code works...

 

Imports Microsoft.DirectX.AudioVideoPlayback

 ....

   Private WithEvents VP As Video
   Private WithEvents AP As Audio          
 
 ....

   'Play Control
   Public Sub Play() Implements IMediaDevice.Play
       Trace.WriteLine("Playing Current")
       Me.tmrPosition.Enabled = True
       Try

           Select Case mType
               Case enumMediaType.Audio
                   AP.Play()

               Case enumMediaType.Video
                   VP.Play()
           End Select

           isPlaying = True
           isPaused = False
       Catch e As Exception
           MsgBox(e.Message)

       End Try
   End Sub
   Public Sub Play(ByVal SourceFileName As String) Implements IMediaDevice.Play
       Me.Stop()
       If Not AP Is Nothing Then AP.Stop() : AP.Dispose()
       If Not VP Is Nothing Then VP.Stop() : VP.Dispose()

       Select Case FindFormat(SourceFileName)
           Case enumMediaType.Audio
               mType = enumMediaType.Audio
               AP = New Audio(SourceFileName)

           Case enumMediaType.Video
               mType = enumMediaType.Video
               VP = New Video(SourceFileName)
               VP.Owner = Me.pctVideoContainer

           Case enumMediaType.Other
               Try
                   'todo: Implement Other action for dx9 player. attempt playback, throw exception
               Catch
               End Try
       End Select
       Me.Play()
   End Sub
   Public Sub Pause() Implements IMediaDevice.Pause
       If isPaused = True Then isPaused = False Else isPaused = True
       Select Case mType
           Case enumMediaType.Audio
               If isPaused Then AP.Pause() Else AP.Play()

           Case enumMediaType.Video
               If isPaused Then VP.Pause() Else VP.Play()
       End Select
   End Sub
   Public Sub [stop]() Implements IMediaDevice.Stop
       Select Case mType
           Case enumMediaType.Audio
               If Not AP Is Nothing Then AP.Stop()

           Case enumMediaType.Video
               If Not VP Is Nothing Then
                   VP.Stop()
                   pctVideoContainer.BackColor = Color.Black : pctVideoContainer.Refresh()
               End If
       End Select

       isPlaying = False
       isPaused = False
       Slider.Percent = 0
       Me.tmrPosition.Enabled = False
       Me.pbMovieLength.Value = 0
       System.Threading.Thread.CurrentThread.Sleep(250)
   End Sub

   Private Sub VP_Ending(ByVal sender As Object, ByVal e As System.EventArgs) Handles VP.Ending
       ' Me.Stop()

       Me.tmrPosition.Enabled = False
       pctVideoContainer.Image = Nothing
       pctVideoContainer.BackgroundImage = Nothing
       pctVideoContainer.BackColor = Color.Black : pctVideoContainer.Refresh()

       isPlaying = False
       isPaused = False

       Me.pbMovieLength.Value = 0
       RaiseEvent EndOfTrack()
   End Sub

   Private Sub AP_Ending(ByVal sender As Object, ByVal e As System.EventArgs) Handles AP.Ending
       ' AP.Stop()

       isPlaying = False
       isPaused = False

       RaiseEvent EndOfTrack()
   End Sub

 

 

I've tried just about everything I can think of... Remarked out some stuff, added a thread.sleep thinking it just needed a bit of time to fully stop playback and dispose, and if I remark out the Dispose lines, it works, but the memory usage grows and grows.

 

 

-Strict-

[AndreRyan]

It might be in the dll itself, try rebooting your computer, if it is a problem with your code it is supposed to highlight the line in the code view not disassemble the program

[dsgreen57]

Been looking at a few examples on the net and I tried the same thing myself in C# and I have got it to work by instead overriding the dispose method within the class... for example.

 

protected override void Dispose(bool disposing)
{
 if (disposing)
 {
    try
    {
       if (audio != null)
       {
          audio.Dispose();
       }
     }
     catch { }
   }
   base.Dispose(disposing);
}

 

and removing any lines where you have written

 

 : AP.Dispose()

 

Sorry it was too early to think how to write the dispose method in Visual Basic.

[Guest Deleted member 22320]

Sounds good for the endgame of the object, but I want to make sure the memory gets released after a track has been played.

 

For instance if there were a bunch of small media files that someone wanted to have played in a looping fashion since the dispose method doesn't get called until everything is closing down, and because you need to create a new playback object for a new file, the memory may not be freed until the program exits (which i would hope it was freed by then, if not theres serious proplems ^_^)

 

Oh, and also the reason I had the dispose call where they were is because my object inherits from UserControl, wich doesnt implement IDisposable. but, i guess i could do that if anything thinks it could make a difference.

[AndreRyan]

.Net uses a Garbage Collector whenever you stop using a object by cutting all references the object is removed when more memory is needed or when a collection cycle takes place. Once you call .Dispose the object will be destroyed by the GC when one of the criteria occur.

[Guest Deleted member 22320]

ya but it still doesnt make sense why the directx class errors out for aparently no reason

[mjmeans]

Did you ever get a solution to this problem? In my case, I am using VS 2003 and MDX April 2005. The error occurs randomly even though I am explicitly disposing the audio object. After loading the DirectX debug symbols and setting up breaks on first chance exceptions, I get the following error:

 

> microsoft.directx.audiovideoplayback.dll!<Module>.AudioWndProc( hWnd = }, uint uMsg = 0x401, uint wParam = 0x0, int lParam = 0x9615fc) + 0x125 bytes