View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0031541||FPC||LCL||public||2017-03-15 09:40||2018-02-21 21:26|
|Reporter||Zoran Vučenović||Assigned To||Florian|
|Fixed in Version||3.1.1|
|Summary||0031541: lazvlc package - Access Violation in control LCLVLCPlayer|
|Description||Control LCLVLCPlayer raises SIGSEGV or Access Violation (depending wether you run it with debugger or not).|
|Steps To Reproduce||First, make sure you have VLC installed in OS.|
Install lazvlc package in the IDE and rebuild Lazarus.
LCLVLCPlayer will appear on tab Multimedia in component palette.
Create new Lazarus Application and put LCLVLCPlayer component on form.
Now try to run the project
- if you run in IDE with debugger you get "Project project1 raised exception class 'External: SIGSEGV'".
- if you run without degugger, you get "Error reading LCLVLCPlayer1.AudioMuted: Access violation."
|Additional Information||Tested on Linux Mint 18.1 Mate (Gtk2 ws, VLC version 2.2.2) and Windows 8.1 (win32/win64 ws, VLC version 2.2.4). Same behaviour.|
Perhaps related to bug 30838, but it is about TVLCMediaListPlayer, which I haven't tried, because I just get Access Violation with main VLC component.
|Tags||No tags attached.|
|Fixed in Revision||38308|
The test application found in components/vlc/test works, but it creates the control in code, not in design time.
It seems that the bug is hidden if you create TLCLVLCPlayer in code. It however appears there also if you try to set AudioMuted property.
This property is published in the component, so when it is put in design time, the program tries to set it and crashes.
||Looks like a bug in the fpc component, not in Lazarus.|
Here it is running fine 64bit Windows 7, Lazarus 1.8.0 r56594 FPC 3.0.4 x86_64-win64-win32/win64, also 64bit Linux Mint KDE 17.3 Lazarus 1.9.0 r56234 FPC 3.0.2 x86_64-linux-gtk2 (tested with example app shipped with Lazarus).
It crashes under Linux, when dropping a TLCLVLCPlayer (so all values default, e.g. AudioMouted=-1) and running it:
Exception=Error reading LCLVLCPlayer1.AudioMuted: Access violation
$00000000006D0A65 line 3183 of lresources.pp
$00000000006C5DD0 line 804 of lresources.pp
$000000000045212C line 2053 of include/customform.inc
$0000000000451F81 line 2041 of include/customform.inc
$0000000000455F81 line 3150 of include/customform.inc
$0000000000462F18 line 2215 of include/application.inc
> Here it is running fine 64bit Windows 7, Lazarus 1.8.0 r56594 FPC 3.0.4 x86_64-win64-win32/win64 (tested with example app shipped with Lazarus).
But when I follow the authors instructions I see the crash at runtime with Laz 1.8 and Laz trunk (both fpc 2.0.4, all 32 bit on Win10 64 bit).
I can repoduce the problem under linux/x86_64 with this code:
LCLVLCPlayer1.AudioMuted := False; // crash
#0 0x0000000000000000 in ?? ()
0000001 0x000000000088c3be in VLC$_$TVLCLIBRARY_$__$$_GETINSTANCE$$PLIBVLC_INSTANCE_T ()
0000002 0x000000000088a079 in VLC$_$TCUSTOMVLCMEDIAPLAYER_$__$$_GETINSTANCE$$PLIBVLC_MEDIA_PLAYER_T ()
0000003 0x0000000000ca4000 in INIT_$TIMEPOPUP_$$_TTIMEPOPUPFORM ()
0000004 0x00000000008899d3 in VLC$_$TCUSTOMVLCMEDIAPLAYER_$__$$_SETAUDIOMUTED$BOOLEAN ()
> I can repoduce the problem under linux/x86_64 with this code:
> LCLVLCPlayer1.AudioMuted := False; // crash
Maybe you have to initialize a instance. This work here:
procedure TForm1.FormCreate(Sender: TObject);
VLCLibrary.Initialize; // <-- !!
FPlayer.AudioMuted := False;
The test project does not do that.
Can the component create an exception with Message 'Missing instance. Maybe you forgot VLCLibrary.Initialize?' instead of AV?
DLL hell again, seems to be similar to my old report 0030762. Somehow LoadLibVLC is not called.
vlc.pp.patch (498 bytes)
Index: packages/libvlc/src/vlc.pp =================================================================== --- packages/libvlc/src/vlc.pp (revision 37764) +++ packages/libvlc/src/vlc.pp (working copy) @@ -679,7 +679,8 @@ procedure TCustomVLCMediaPlayer.SetAudioMuted(AValue: Boolean); begin - libvlc_audio_set_mute(instance, ord(AValue)); + if Assigned(FInstance) then + libvlc_audio_set_mute(instance, ord(AValue)); end; procedure TCustomVLCMediaPlayer.SetFitWindow(AValue: Boolean);
vlc.pp.patch (498 bytes)
This issue has to be moved to FPC. Patch added.
> The test project does not do that.
Yes, I read that to late - sorry! After WPs hint, I can see the issue and could fix it (not such a big one, I do the same, as is done for the other properties). Tested with 64bit Windows 7 Lazarus 1.9.0 r56789 FPC 3.1.1 i386-win32-win32/win64, 64bit Linux Mint KDE 17.3 GTK2 Lazarus 1.9.0 r56234 FPC 3.0.2 x86_64-linux-gtk2.
Yes, the OP's steps to reproduce don't lead to a crash any more (Win 10).
But now that there's a VLCPlayer on the form I cannot set the AudioMuted in Object Inspector. Same with FullScreenMode, AudioDelay, AudioVolume, Channel, Chapter.
Yes this can only be done at runtime or the library has to be loaded into the IDE.
IMHO the designtime not reachable properties has to be moved to public section.
At least, this limit isn't a big showstopper but it need to be documented, if not already be done.
> IMHO the designtime not reachable properties has to be moved to public section.
I'd agree, but maybe the author initially planned to load the DLL when the component is clicked onto the form and did not implement this feature?
|2017-03-15 09:40||Zoran Vučenović||New Issue|
|2017-03-15 09:44||Zoran Vučenović||Relationship added||related to 0030838|
|2017-03-15 10:00||Zoran Vučenović||Note Added: 0098915|
|2017-06-17 22:19||Juha Manninen||Relationship added||related to 0032030|
|2017-12-19 19:15||Mattias Gaertner||Note Added: 0104855|
|2017-12-19 20:40||Michl||Note Added: 0104857|
|2017-12-19 20:40||Michl||Note Edited: 0104857||View Revisions|
|2017-12-19 20:46||Mattias Gaertner||Note Added: 0104858|
|2017-12-19 20:55||wp||Note Added: 0104859|
|2017-12-19 21:15||Mattias Gaertner||Note Added: 0104860|
|2017-12-19 21:18||Michl||Note Edited: 0104857||View Revisions|
|2017-12-19 21:55||Michl||Note Added: 0104861|
|2017-12-19 21:57||Michl||Note Edited: 0104861||View Revisions|
|2017-12-19 22:16||Michl||Assigned To||=> Michl|
|2017-12-19 22:16||Michl||Status||new => assigned|
|2017-12-19 22:22||Mattias Gaertner||Note Added: 0104862|
|2017-12-19 22:26||wp||Note Added: 0104863|
|2017-12-19 22:29||wp||Note Edited: 0104863||View Revisions|
|2017-12-19 22:30||Michl||Assigned To||Michl =>|
|2017-12-19 22:35||Michl||File Added: vlc.pp.patch|
|2017-12-19 22:36||Michl||Assigned To||=> Michl|
|2017-12-19 22:36||Michl||Status||assigned => new|
|2017-12-19 22:36||Michl||Assigned To||Michl =>|
|2017-12-19 22:40||Michl||Note Added: 0104864|
|2017-12-19 22:44||Michl||Note Edited: 0104864||View Revisions|
|2017-12-19 23:18||wp||Note Added: 0104866|
|2017-12-19 23:31||Michl||Note Added: 0104867|
|2017-12-19 23:46||Maxim Ganetsky||Project||Lazarus => FPC|
|2017-12-20 00:01||wp||Note Added: 0104868|
|2018-02-21 21:26||Florian||Fixed in Revision||=> 38308|
|2018-02-21 21:26||Florian||Status||new => resolved|
|2018-02-21 21:26||Florian||Fixed in Version||=> 3.1.1|
|2018-02-21 21:26||Florian||Resolution||open => fixed|
|2018-02-21 21:26||Florian||Assigned To||=> Florian|