Difference between revisions of "Using libvlc with Delphi"

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m (See also: ActiveX/Delphi)
 
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−
This is a sample code to play media files using libvlc with Delphi (test with Delphi XE2 VCL form, VLC 1.1.11).
+
{{See also|ActiveX/Delphi}}
 +
{{example code|for=LibVLC}}
 +
This is a sample code to play media files using [[libVLC]] with Delphi (test with Delphi XE2 VCL form, VLC 1.1.11).
  
 
== Form design  ==
 
== Form design  ==
Line 8: Line 10:
  
 
=== Implementations  ===
 
=== Implementations  ===
−
<pre>unit Unit1;
+
<syntaxhighlight lang="delphi">unit Unit1;
 
interface
 
interface
  
Line 42: Line 44:
  
 
var
 
var
−
   libvlc_media_new_path             &nbsp;: function(p_instance&nbsp;: Plibvlc_instance_t; path&nbsp;: PAnsiChar)&nbsp;: Plibvlc_media_t; cdecl;
+
   libvlc_media_new_path             : function(p_instance : Plibvlc_instance_t; path : PAnsiChar) : Plibvlc_media_t; cdecl;
−
   libvlc_media_new_location         &nbsp;: function(p_instance&nbsp;: plibvlc_instance_t; psz_mrl&nbsp;: PAnsiChar)&nbsp;: Plibvlc_media_t; cdecl;
+
   libvlc_media_new_location         : function(p_instance : plibvlc_instance_t; psz_mrl : PAnsiChar) : Plibvlc_media_t; cdecl;
−
   libvlc_media_player_new_from_media&nbsp;: function(p_media&nbsp;: Plibvlc_media_t)&nbsp;: Plibvlc_media_player_t; cdecl;
+
   libvlc_media_player_new_from_media : function(p_media : Plibvlc_media_t) : Plibvlc_media_player_t; cdecl;
−
   libvlc_media_player_set_hwnd     &nbsp;: procedure(p_media_player&nbsp;: Plibvlc_media_player_t; drawable&nbsp;: Pointer); cdecl;
+
   libvlc_media_player_set_hwnd       : procedure(p_media_player : Plibvlc_media_player_t; drawable : Pointer); cdecl;
−
   libvlc_media_player_play         &nbsp;: procedure(p_media_player&nbsp;: Plibvlc_media_player_t); cdecl;
+
   libvlc_media_player_play           : procedure(p_media_player : Plibvlc_media_player_t); cdecl;
−
   libvlc_media_player_stop         &nbsp;: procedure(p_media_player&nbsp;: Plibvlc_media_player_t); cdecl;
+
   libvlc_media_player_stop           : procedure(p_media_player : Plibvlc_media_player_t); cdecl;
−
   libvlc_media_player_release       &nbsp;: procedure(p_media_player&nbsp;: Plibvlc_media_player_t); cdecl;
+
   libvlc_media_player_release       : procedure(p_media_player : Plibvlc_media_player_t); cdecl;
−
   libvlc_media_player_is_playing   &nbsp;: function(p_media_player&nbsp;: Plibvlc_media_player_t)&nbsp;: Integer; cdecl;
+
   libvlc_media_player_is_playing     : function(p_media_player : Plibvlc_media_player_t) : Integer; cdecl;
−
   libvlc_media_release             &nbsp;: procedure(p_media&nbsp;: Plibvlc_media_t); cdecl;
+
   libvlc_media_release               : procedure(p_media : Plibvlc_media_t); cdecl;
−
   libvlc_new                       &nbsp;: function(argc&nbsp;: Integer; argv&nbsp;: PAnsiChar)&nbsp;: Plibvlc_instance_t; cdecl;
+
   libvlc_new                         : function(argc : Integer; argv : PAnsiChar) : Plibvlc_instance_t; cdecl;
−
   libvlc_release                   &nbsp;: procedure(p_instance&nbsp;: Plibvlc_instance_t); cdecl;
+
   libvlc_release                     : procedure(p_instance : Plibvlc_instance_t); cdecl;
  
 
   vlcLib: integer;
 
   vlcLib: integer;
Line 58: Line 60:
 
   vlcMedia: plibvlc_media_t;
 
   vlcMedia: plibvlc_media_t;
 
   vlcMediaPlayer: plibvlc_media_player_t;
 
   vlcMediaPlayer: plibvlc_media_player_t;
−
</pre>  
+
</syntaxhighlight>  
 
=== Get VLC installation path  ===
 
=== Get VLC installation path  ===
  
−
Normally, the library libvlc.dll is in "C:\Program files\Videolan\VLC\". This function read registry to get the correct VLC installation path, stored in key HKEY_LOCAL_MACHINE\Software\VideoLAN\VLC.  
+
Normally, the library libvlc.dll is in <code>"C:\Program files\Videolan\VLC\"</code>. This function read registry to get the correct VLC installation path, stored in key <code>HKEY_LOCAL_MACHINE\Software\VideoLAN\VLC</code>.  
−
<pre>// -----------------------------------------------------------------------------
+
<syntaxhighlight lang="delphi">
 +
// -----------------------------------------------------------------------------
 
// Read registry to get VLC installation path
 
// Read registry to get VLC installation path
 
// -----------------------------------------------------------------------------
 
// -----------------------------------------------------------------------------
Line 72: Line 75:
 
   Key: PWideChar;
 
   Key: PWideChar;
 
begin
 
begin
−
   Result&nbsp;:= '';
+
   Result := '';
−
   Key&nbsp;:= 'Software\VideoLAN\VLC';
+
   Key := 'Software\VideoLAN\VLC';
 
   if RegOpenKeyEx(HKEY_LOCAL_MACHINE, Key, 0, KEY_READ, Handle) = ERROR_SUCCESS then
 
   if RegOpenKeyEx(HKEY_LOCAL_MACHINE, Key, 0, KEY_READ, Handle) = ERROR_SUCCESS then
 
   begin
 
   begin
Line 80: Line 83:
 
       SetLength(Result, DataSize);
 
       SetLength(Result, DataSize);
 
       RegQueryValueEx(Handle, 'InstallDir', nil, @RegType, PByte(@Result[1]), @DataSize);
 
       RegQueryValueEx(Handle, 'InstallDir', nil, @RegType, PByte(@Result[1]), @DataSize);
−
       Result[DataSize]&nbsp;:= '\';
+
       Result[DataSize] := '\';
 
     end
 
     end
 
     else Showmessage('Error on reading registry');
 
     else Showmessage('Error on reading registry');
 
     RegCloseKey(Handle);
 
     RegCloseKey(Handle);
−
     Result&nbsp;:= String(PChar(Result));
+
     Result := String(PChar(Result));
 
   end;
 
   end;
 
end;
 
end;
−
</pre>
+
</syntaxhighlight>
 
=== Load libvlc library into memory ===
 
=== Load libvlc library into memory ===
  
 
Next, load library libvlc.dll into memory
 
Next, load library libvlc.dll into memory
−
<pre>// -----------------------------------------------------------------------------
+
<syntaxhighlight lang="delphi">
 +
// -----------------------------------------------------------------------------
 
// Load libvlc library into memory
 
// Load libvlc library into memory
 
// -----------------------------------------------------------------------------
 
// -----------------------------------------------------------------------------
Line 100: Line 104:
 
end;
 
end;
  
−
</pre>
+
</syntaxhighlight>
 
=== Get address of libvlc functions ===
 
=== Get address of libvlc functions ===
  
 
This will get address of libvlc functions. Only neccessary functions loaded for this sample code, please refer to libvlc document if you need more functions
 
This will get address of libvlc functions. Only neccessary functions loaded for this sample code, please refer to libvlc document if you need more functions
−
<pre>// -----------------------------------------------------------------------------
+
<syntaxhighlight lang="delphi">
 +
// -----------------------------------------------------------------------------
 
function GetAProcAddress(handle: integer; var addr: Pointer; procName: string; failedList: TStringList): integer;
 
function GetAProcAddress(handle: integer; var addr: Pointer; procName: string; failedList: TStringList): integer;
 
begin
 
begin
Line 134: Line 139:
 
end;
 
end;
  
−
</pre>
+
</syntaxhighlight>
−
=== Create form ===
+
=== Create form ===
  
−
Load library on form create. If you use a incompartible libvlc version (older or newer than this demo), some functions may not be correct (obsolete or agruments changed). In this case, program will display a list of functions failed to load, and you can correct these according to your libvlc version.
+
Load library on form create. If you use a incompartible libvlc version (older or newer than this demo), some functions may not be correct (obsolete or agruments changed). In this case, program will display a list of functions failed to load, and you must rewrite these function prototype according to your libvlc version.  
−
<pre>// -----------------------------------------------------------------------------
+
<syntaxhighlight lang="delphi">
 +
// -----------------------------------------------------------------------------
 
procedure TForm1.FormCreate(Sender: TObject);
 
procedure TForm1.FormCreate(Sender: TObject);
 
var sL: TStringList;
 
var sL: TStringList;
Line 159: Line 165:
 
end;
 
end;
  
−
</pre>
+
</syntaxhighlight>
−
[[Category:Coding]] [[Category:Delphi]]
+
 
 +
=== Close form ===
 +
 
 +
Remember to unload libvlc library when exit
 +
<syntaxhighlight lang="delphi">
 +
// -----------------------------------------------------------------------------
 +
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
 +
begin
 +
  // unload vlc library
 +
  FreeLibrary(vlclib);
 +
end;
 +
</syntaxhighlight>
 +
=== Play a media<br> ===
 +
 
 +
Play a media (file or MURL) when user clicks on button "Play"
 +
<syntaxhighlight lang="delphi">
 +
// -----------------------------------------------------------------------------
 +
procedure TForm1.btnPlayClick(Sender: TObject);
 +
begin
 +
  // create new vlc instance
 +
  vlcInstance := libvlc_new(0, nil);
 +
  // create new vlc media from file
 +
  vlcMedia := libvlc_media_new_path(vlcInstance, 'e:\udp\239.10.10.9.ts');
 +
 
 +
  // if you want to play from network, use libvlc_media_new_location instead
 +
  // vlcMedia := libvlc_media_new_location(vlcInstance, 'udp://@225.2.1.27:5127');
 +
 
 +
  // create new vlc media player
 +
  vlcMediaPlayer := libvlc_media_player_new_from_media(vlcMedia);
 +
 
 +
  // now no need the vlc media, free it
 +
  libvlc_media_release(vlcMedia);
 +
 
 +
  // play video in a TPanel, if not call this routine, vlc media will open a new window
 +
  libvlc_media_player_set_hwnd(vlcMediaPlayer, Pointer(Panel1.Handle));
 +
 
 +
  // play media
 +
  libvlc_media_player_play(vlcMediaPlayer);
 +
end;
 +
</syntaxhighlight>
 +
=== Stop a media ===
 +
 
 +
And stop playing when user clicks on button "Stop"
 +
<syntaxhighlight lang="delphi">
 +
// -----------------------------------------------------------------------------
 +
procedure TForm1.btnStopClick(Sender: TObject);
 +
begin
 +
  if not Assigned(vlcMediaPlayer) then begin
 +
    Showmessage('Not playing');
 +
    Exit;
 +
  end;
 +
  // stop vlc media player
 +
  libvlc_media_player_stop(vlcMediaPlayer);
 +
  // and wait until it completely stops
 +
  while libvlc_media_player_is_playing(vlcMediaPlayer) = 1 do begin
 +
    Sleep(100);
 +
  end;
 +
  // release vlc media player
 +
  libvlc_media_player_release(vlcMediaPlayer);
 +
  vlcMediaPlayer := nil;
 +
 
 +
  // release vlc instance
 +
  libvlc_release(vlcInstance);
 +
end;
 +
 
 +
</syntaxhighlight>
 +
 
 +
[[Category:Coding]]
 +
[[Category:libVLC]]

Latest revision as of 09:06, 19 March 2019

See also: ActiveX/Delphi
This page contains example code for LibVLC.

This is a sample code to play media files using libVLC with Delphi (test with Delphi XE2 VCL form, VLC 1.1.11).

Form design

Use a simple form with 3 control : Panel1 (TPanel) to display video, btnPlay (TButton) to play media, and btnStop (TButton) to stop playing

Full source code

Implementations

unit Unit1;
interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls;

type
  TForm1 = class(TForm)
    btnPlay: TButton;
    btnStop: TButton;
    Panel1: TPanel;
    procedure btnPlayClick(Sender: TObject);
    procedure btnStopClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

  plibvlc_instance_t        = type Pointer;
  plibvlc_media_player_t    = type Pointer;
  plibvlc_media_t           = type Pointer;

var
  Form1: TForm1;

implementation

{$R *.dfm}

var
  libvlc_media_new_path              : function(p_instance : Plibvlc_instance_t; path : PAnsiChar) : Plibvlc_media_t; cdecl;
  libvlc_media_new_location          : function(p_instance : plibvlc_instance_t; psz_mrl : PAnsiChar) : Plibvlc_media_t; cdecl;
  libvlc_media_player_new_from_media : function(p_media : Plibvlc_media_t) : Plibvlc_media_player_t; cdecl;
  libvlc_media_player_set_hwnd       : procedure(p_media_player : Plibvlc_media_player_t; drawable : Pointer); cdecl;
  libvlc_media_player_play           : procedure(p_media_player : Plibvlc_media_player_t); cdecl;
  libvlc_media_player_stop           : procedure(p_media_player : Plibvlc_media_player_t); cdecl;
  libvlc_media_player_release        : procedure(p_media_player : Plibvlc_media_player_t); cdecl;
  libvlc_media_player_is_playing     : function(p_media_player : Plibvlc_media_player_t) : Integer; cdecl;
  libvlc_media_release               : procedure(p_media : Plibvlc_media_t); cdecl;
  libvlc_new                         : function(argc : Integer; argv : PAnsiChar) : Plibvlc_instance_t; cdecl;
  libvlc_release                     : procedure(p_instance : Plibvlc_instance_t); cdecl;

  vlcLib: integer;
  vlcInstance: plibvlc_instance_t;
  vlcMedia: plibvlc_media_t;
  vlcMediaPlayer: plibvlc_media_player_t;

Get VLC installation path

Normally, the library libvlc.dll is in "C:\Program files\Videolan\VLC\". This function read registry to get the correct VLC installation path, stored in key HKEY_LOCAL_MACHINE\Software\VideoLAN\VLC. 

// -----------------------------------------------------------------------------
// Read registry to get VLC installation path
// -----------------------------------------------------------------------------
function GetVLCLibPath: String;
var
  Handle: HKEY;
  RegType: Integer;
  DataSize: Cardinal;
  Key: PWideChar;
begin
  Result := '';
  Key := 'Software\VideoLAN\VLC';
  if RegOpenKeyEx(HKEY_LOCAL_MACHINE, Key, 0, KEY_READ, Handle) = ERROR_SUCCESS then
  begin
    if RegQueryValueEx(Handle, 'InstallDir', nil, @RegType, nil, @DataSize) = ERROR_SUCCESS then
    begin
      SetLength(Result, DataSize);
      RegQueryValueEx(Handle, 'InstallDir', nil, @RegType, PByte(@Result[1]), @DataSize);
      Result[DataSize] := '\';
    end
    else Showmessage('Error on reading registry');
    RegCloseKey(Handle);
    Result := String(PChar(Result));
  end;
end;

Load libvlc library into memory

Next, load library libvlc.dll into memory 

// -----------------------------------------------------------------------------
// Load libvlc library into memory
// -----------------------------------------------------------------------------
function LoadVLCLibrary(APath: string): integer;
begin
  Result := LoadLibrary(PWideChar(APath + '\libvlccore.dll'));
  Result := LoadLibrary(PWideChar(APath + '\libvlc.dll'));
end;

Get address of libvlc functions

This will get address of libvlc functions. Only neccessary functions loaded for this sample code, please refer to libvlc document if you need more functions 

// -----------------------------------------------------------------------------
function GetAProcAddress(handle: integer; var addr: Pointer; procName: string; failedList: TStringList): integer;
begin
  addr := GetProcAddress(handle, PWideChar(procName));
  if Assigned(addr) then Result := 0
  else begin
    if Assigned(failedList) then failedList.Add(procName);
    Result := -1;
  end;
end;
// -----------------------------------------------------------------------------
// Get address of libvlc functions
// -----------------------------------------------------------------------------
function LoadVLCFunctions(vlcHandle: integer; failedList: TStringList): Boolean;
begin
  GetAProcAddress(vlcHandle, @libvlc_new, 'libvlc_new', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_new_location, 'libvlc_media_new_location', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_player_new_from_media, 'libvlc_media_player_new_from_media', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_release, 'libvlc_media_release', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_player_set_hwnd, 'libvlc_media_player_set_hwnd', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_player_play, 'libvlc_media_player_play', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_player_stop, 'libvlc_media_player_stop', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_player_release, 'libvlc_media_player_release', failedList);
  GetAProcAddress(vlcHandle, @libvlc_release, 'libvlc_release', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_player_is_playing, 'libvlc_media_player_is_playing', failedList);
  GetAProcAddress(vlcHandle, @libvlc_media_new_path, 'libvlc_media_new_path', failedList);
  // if all functions loaded, result is an empty list, otherwise result is a list of functions failed
  Result := failedList.Count = 0;
end;

Create form

Load library on form create. If you use a incompartible libvlc version (older or newer than this demo), some functions may not be correct (obsolete or agruments changed). In this case, program will display a list of functions failed to load, and you must rewrite these function prototype according to your libvlc version. 

// -----------------------------------------------------------------------------
procedure TForm1.FormCreate(Sender: TObject);
var sL: TStringList;
begin
  // load vlc library
  vlclib := LoadVLCLibrary(GetVLCLibPath());
  if vlclib = 0 then begin
    Showmessage('Load vlc library failed');
    Exit;
  end;
  // sL will contains list of functions fail to load
  sL := TStringList.Create;
  if not LoadVLCFunctions(vlclib, sL) then begin
    Showmessage('Some functions failed to load : ' + #13#10 + sL.Text);
    FreeLibrary(vlclib);
    sL.Free;
    Exit;
  end;
  sL.Free;
end;

Close form

Remember to unload libvlc library when exit 

// -----------------------------------------------------------------------------
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  // unload vlc library
  FreeLibrary(vlclib);
end;

Play a media

Play a media (file or MURL) when user clicks on button "Play" 

// -----------------------------------------------------------------------------
procedure TForm1.btnPlayClick(Sender: TObject);
begin
  // create new vlc instance
  vlcInstance := libvlc_new(0, nil);
  // create new vlc media from file
  vlcMedia := libvlc_media_new_path(vlcInstance, 'e:\udp\239.10.10.9.ts');

  // if you want to play from network, use libvlc_media_new_location instead
  // vlcMedia := libvlc_media_new_location(vlcInstance, 'udp://@225.2.1.27:5127');

  // create new vlc media player
  vlcMediaPlayer := libvlc_media_player_new_from_media(vlcMedia);

  // now no need the vlc media, free it
  libvlc_media_release(vlcMedia);

  // play video in a TPanel, if not call this routine, vlc media will open a new window
  libvlc_media_player_set_hwnd(vlcMediaPlayer, Pointer(Panel1.Handle));

  // play media
  libvlc_media_player_play(vlcMediaPlayer);
end;

Stop a media

And stop playing when user clicks on button "Stop" 

// -----------------------------------------------------------------------------
procedure TForm1.btnStopClick(Sender: TObject);
begin
  if not Assigned(vlcMediaPlayer) then begin
    Showmessage('Not playing');
    Exit;
  end;
  // stop vlc media player
  libvlc_media_player_stop(vlcMediaPlayer);
  // and wait until it completely stops
  while libvlc_media_player_is_playing(vlcMediaPlayer) = 1 do begin
    Sleep(100);
  end;
  // release vlc media player
  libvlc_media_player_release(vlcMediaPlayer);
  vlcMediaPlayer := nil;

  // release vlc instance
  libvlc_release(vlcInstance);
end;
Retrieved from "https://wiki.videolan.org/index.php?title=Using_libvlc_with_Delphi&oldid=59973"