Sub PlaylistAdd( _
   ByVal _pExternOrRef As Object, _
   ByVal _bsPath As String, _
   ByVal _bsParam As String, _
   ByRef _pnIndex As Integer, _
   ByRef _ppPlaylistItem As MItem _
) 

void PlaylistAdd( 
   object _pExternOrRef,
   string _bsPath,
   string _bsParam,
   out int _pnIndex,
   out MItem _ppPlaylistItem
)

procedure PlaylistAdd( 
    _pExternOrRef: TObject;
    _bsPath: String;
    _bsParam: String;
   Out  _pnIndex: Integer;
   Out  _ppPlaylistItem: MItem
); 

void PlaylistAdd( 
   IUnknown* _pExternOrRef,
   BSTR* _bsPath,
   BSTR* _bsParam,
   [PARAMFLAG::Out] int _pnIndex,
   [PARAMFLAG::Out] MItem* _ppPlaylistItem
) 

Parameters

_pExternOrRef

reference to external object (for example, live source)

_bsPath

path of the item

_bsParam

additional parameters of element (“Live” to add live source, “Playlist” to add playlist). If you want to add a new playlist with any file then you should use PlaylistAdd( “my_file.avi”, “playlist”). If you add file, you can set file properties here (like in FileNameSet method), see MFile object: properties.

_pnIndex

place of element in playlist
Possible values:

• 0 - insert new file to first position of playlist: [newfile] [first] ... [last]
• 1 - insert new file to second position of playlist: [first] [newfile] ... [last]
• etc.
• -1 - insetf new file to the end of playlist: [first] ... [last] [newfile]
• -2 - insert new file to second position from the end of playlist: [first] ... [newfile] [last]
• -3 - insert new file to third position from the end of playlist: [first] ... [newfile] [pre-last] [last]
• etc.

_ppPlaylistItem

output playlist item

Here is example or playlist initialization and adding a file to it:

Dim myPlaylist As New MPlaylistClass()
myPlaylist.PreviewWindowSet("", panelPreview.Handle.ToInt32())
myPlaylist.PreviewEnable("", 1, 1)
myPlaylist.ObjectStart(New Object())
'Insert clip at the end of playlist
Dim nIndex As Integer = -1
Dim pFile As MItem
Dim strPath As String = "d:\clips\SampleClip1.wmv"
myPlaylist.PlaylistAdd(Nothing, strPath, "", nIndex, pFile)
myPlaylist.FilePlayStart()

MPlaylistClass myPlaylist = new MPlaylistClass();
myPlaylist.PreviewWindowSet("", panelPreview.Handle.ToInt32()); 
myPlaylist.PreviewEnable("", 1, 1);
myPlaylist.ObjectStart(new object());
//Insert clip at the end of playlist
int nIndex = -1;
MItem pFile;
string strPath = @"d:\clips\SampleClip1.wmv";
myPlaylist.PlaylistAdd(null, strPath, "", ref nIndex, out pFile);
myPlaylist.FilePlayStart();

var
nIndex: integer;
pItem: MItem;
myPlaylist: MPlaylist;
myPreview: IMPreview;
myEvents: TEvents;
myFile:IMFile;
myObject:IMObject;
cookie: LONG_PTR;
begin
myPlaylist:= CreateComObject(CLASS_MPlaylist) as MPlaylist;
myPreview:= myPlaylist as IMPreview;
myObject:= myPlaylist as IMObject;
myEvents:=TEvents.Create();
myObject.ObjectCallbackSet(myEvents, cookie);
myFile:=myPlaylist as IMFile;
myPreview.PreviewWindowSet('', panelPreview.Handle);
myPreview.PreviewEnable('', 1, 1);
nIndex:=-1;
myPlaylist.PlaylistAdd(nil, 'c:\myFile.avi', '', nIndex, pItem);
myFile.FilePlayStart();
end;

Reference

IMPlaylist Interface
IMPlaylist Members