AxVLC hangs when changing items rapidly

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truth
Blank Cone
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Joined: 06 Apr 2017 09:55

AxVLC hangs when changing items rapidly

Postby truth » 10 Apr 2017 03:24

I'm using the AxVLC component in a legacy VB6 application. If I follow the example from the documentation (https://wiki.videolan.org/Documentation ... ist_object) it functions as expected. That is, if I clear the current playlist, add the desired media item to the playlist, and then execute vlc.Playlist.playItem(0), all is well. Other ways of playing items via a .Playlist with more than one item have proven not to work at all.

Using the above process to render video items (.Playlist.Items.Clear, .Playlist.Add, .Playlist.playItem(0)), the application hangs when the user tries to advance too quickly from one event (playlist item) to the next. Our application plays many diverse items (audio, video, executables, PowerPoint presentations, MS Office documents, PDFs, etc.) and therefore we maintain our own multi-media playlist. During playback, our users can use the right and left keyboard arrow keys to advance from one item to the next/previous. If a user actually holds down the right arrow key, for example, and engages the auto-repeat function, after about 3 or 4 events, the AxVLC seems to hang and the entire application becomes unresponsive.

The above does not happen in the standalone VLC desktop app, of course, so either I'm using vlc.Playlist improperly or there is an issue/bug concerning the speed at which the component can transition from one item to the next.

Included below is the rather straightforward code for our VB6 User Control which wraps AxVLC. Included are some (commented out) sections where I attempted to make the PlaylistPlay method atomic - which had no discernable effect.

Code: Select all

Private strPlaylistURL As String Private vlcControl As Object Private hMutex As Long Public Event MediaPlayerEncounteredError() Public Event MediaPlayerEndReached() Public Event MediaPlayerNothingSpecial() Public Event MediaPlayerStopped() Public Event MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single) Public Event MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single) Public Event KeyDown(KeyCode As Integer, Shift As Integer) Public WithEvents vmpPreview As AXVLC.VLCPlugin2 'Private Declare Function CreateMutex Lib "kernel32" Alias "CreateMutexA" (ByVal lpMutexAttributes As Long, ByVal bInitialOwner As Long, ByVal lpName As String) As Long 'Private Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long 'Private Declare Function ReleaseMutex Lib "kernel32" (ByVal hMutex As Long) As Long 'Private Type SECURITY_ATTRIBUTES ' nLength As Long ' lpSecurityDescriptor As Long ' bInheritHandle As Long 'End Type Private Sub UserControl_Initialize() Set vlcControl = Controls.Add("VideoLan.VLCPlugin", "vlcControl") vlcControl.visible = True Set vmpPreview = vlcControl.object 'Remove pylon logo vmpPreview.Branding = False 'remove VLC pylon logo by default vmpPreview.ToolBar = False 'disable video control bar by default vmpPreview.fullScreenEnabled = False 'disable full screen video mode by default ' hMutex = CreateMutex(0, 1, vbNullString) End Sub Private Sub UserControl_KeyDown(KeyCode As Integer, Shift As Integer) RaiseEvent KeyDown(KeyCode, Shift) End Sub Private Sub UserControl_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single) RaiseEvent MouseMove(Button, Shift, X, Y) End Sub Private Sub UserControl_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single) RaiseEvent MouseUp(Button, Shift, X, Y) End Sub Private Sub UserControl_Resize() With vlcControl .Top = 0 .Left = 0 .Width = Width .Height = Height .ZOrder 1 End With End Sub Private Sub tmrVideoDimensionsTimeout_Timer() tmrVideoDimensionsTimeout.Enabled = False End Sub Public Sub PlaylistPlay(strURL As String) ' WaitForSingleObject hMutex, 10000 ' tmrVideoDimensionsTimeout.Enabled = True ' While IsPlaying And tmrVideoDimensionsTimeout.Enabled ' DoEvents ' Wend ' tmrVideoDimensionsTimeout.Enabled = False strPlaylistURL = strURL PlaylistClear Play PlaylistAdd(strURL) ' Play ' ReleaseMutex hMutex End Sub Public Sub Play(Optional lngID As Long = 0) Debug.Print "vmpPreview.Playlist.playItem "; lngID; vmpPreview.Playlist.Items.Count vmpPreview.Playlist.playItem lngID ' vmpPreview.Playlist.Play End Sub Public Function PlaylistAdd(strURL As String) As Long Const VIDEO_TS = "video_ts.ifo" Const options = ":avcodec-hw=none" Dim lngID As Long If StrConv(GetFileName(strURL), vbLowerCase) <> VIDEO_TS Then PlaylistAdd = vmpPreview.Playlist.Add("file:///" + strURL, , options) Else PlaylistAdd = vmpPreview.Playlist.Add("dvd:///" + GetFileDirectory(strURL), , options) End If End Function Public Sub PlaylistClear() ' Static clearing As Boolean ' If Not clearing Then ' clearing = True tmrVideoDimensionsTimeout.Enabled = True While IsPlaying And tmrVideoDimensionsTimeout.Enabled DoEvents Wend tmrVideoDimensionsTimeout.Enabled = False vmpPreview.Playlist.Items.Clear ' clearing = False ' End If End Sub Public Sub PlaylistStop() vmpPreview.Playlist.pause volume = 100 vmpPreview.Playlist.stop Debug.Print "IsPlaying: "; IsPlaying ' tmrVideoDimensionsTimeout.Enabled = True ' While IsPlaying And tmrVideoDimensionsTimeout.Enabled ' DoEvents ' Wend ' tmrVideoDimensionsTimeout.Enabled = False End Sub Public Sub FadeIn() For intVolume = 0 To 100 Step 10 volume = intVolume Sleep 100 Next End Sub Public Sub FadeOut() For intVolume = 100 To 0 Step 10 volume = intVolume Sleep 100 Next End Sub Public Property Get volume() As Integer volume = vmpPreview.volume End Property Public Property Let volume(nVolume As Integer) vmpPreview.volume = nVolume End Property Public Property Get IsPlaying() As Boolean IsPlaying = vmpPreview.Playlist.IsPlaying End Property Public Property Get PlaylistURL() As String If IsPlaying Then Dim nCurrentItem As Integer nCurrentItem = vmpPreview.Playlist.currentItem If nCurrentItem > -1 Then PlaylistURL = strPlaylistURL End If End Property Public Property Get VideoWidth() As Integer tmrVideoDimensionsTimeout.Enabled = True While VideoWidth <= 10 And tmrVideoDimensionsTimeout.Enabled DoEvents VideoWidth = vmpPreview.video.Width Wend tmrVideoDimensionsTimeout.Enabled = False End Property Public Property Get VideoHeight() As Integer tmrVideoDimensionsTimeout.Enabled = True While VideoHeight <= 10 And tmrVideoDimensionsTimeout.Enabled DoEvents VideoHeight = vmpPreview.video.Height Wend tmrVideoDimensionsTimeout.Enabled = False End Property Public Property Get VideoControlBarVisible() As Boolean VideoControlBarVisible = vmpPreview.ToolBar End Property Public Property Let VideoControlBarVisible(visible As Boolean) vmpPreview.ToolBar = visible End Property Public Property Let OwnerForm(objOwner As Object) Set objParent = objOwner End Property 'Private Sub vmpPreview_MediaPlayerBackward() ' Debug.Print "MediaPlayerBackward" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerBuffering(ByVal cache As Long) ' Debug.Print "MediaPlayerBuffering" 'End Sub ' Private Sub vmpPreview_MediaPlayerEncounteredError() RaiseEvent MediaPlayerEncounteredError Debug.Print "MediaPlayerEncounteredError" End Sub Private Sub vmpPreview_MediaPlayerEndReached() RaiseEvent MediaPlayerEndReached Debug.Print "MediaPlayerEndReached" End Sub 'Private Sub vmpPreview_MediaPlayerForward() ' Debug.Print "MediaPlayerForward" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerLengthChanged(ByVal length As Long) ' Debug.Print "MediaPlayerLengthChanged" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerMediaChanged() ' Debug.Print "MediaPlayerMediaChanged" 'End Sub ' Private Sub vmpPreview_MediaPlayerNothingSpecial() RaiseEvent MediaPlayerNothingSpecial Debug.Print "MediaPlayerNothingSpecial" End Sub 'Private Sub vmpPreview_MediaPlayerOpening() ' Debug.Print "MediaPlayerOpening" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerPausableChanged(ByVal pausable As Boolean) ' Debug.Print "MediaPlayerPausableChanged" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerPaused() ' Debug.Print "MediaPlayerPaused" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerPlaying() ' Debug.Print "MediaPlayerPlaying" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerPositionChanged(ByVal position As Single) ' Debug.Print "MediaPlayerPositionChanged" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerSeekableChanged(ByVal seekable As Boolean) ' Debug.Print "MediaPlayerSeekableChanged" 'End Sub ' Private Sub vmpPreview_MediaPlayerStopped() RaiseEvent MediaPlayerStopped Debug.Print "MediaPlayerStopped" End Sub 'Private Sub vmpPreview_MediaPlayerTimeChanged(ByVal time As Long) ' Debug.Print "MediaPlayerTimeChanged" 'End Sub ' 'Private Sub vmpPreview_MediaPlayerTitleChanged(ByVal title As Long) ' Debug.Print "MediaPlayerTitleChanged" 'End Sub

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