How do you loop a video using DSPack? - delphi

Question

I've got a very simple program that uses DSPack from within Delphi 2010. I have a form with a TFilterGraph and a TVideoWindow. The video plays and renders nicely. I can't seem to figure out how to make the video loop back to the beginning when it ends.
How do you make a video automatically loop using DSPack?
Code
unit Unit21;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, DSPack, ExtCtrls;
type
TForm21 = class(TForm)
FilterGraph1: TFilterGraph;
OpenDialog1: TOpenDialog;
Button1: TButton;
Button2: TButton;
Panel1: TPanel;
VideoWindow1: TVideoWindow;
Panel2: TPanel;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form21: TForm21;
implementation
{$R *.dfm}
procedure TForm21.Button1Click(Sender: TObject);
begin
OpenDialog1.InitialDir := ExtractFilePath(ParamStr(0));
if OpenDialog1.Execute then
begin
if not FilterGraph1.Active then FilterGraph1.Active:= True;
VideoWindow1.FilterGraph:= FilterGraph1;
FilterGraph1.RenderFile(OpenDialog1.Filename);
FilterGraph1.Play;
end;
end;
procedure TForm21.Button2Click(Sender: TObject);
begin
FilterGraph1.Stop;
end;
procedure TForm21.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
FilterGraph1.ClearGraph;
FilterGraph1.Active:= False;
end;
end.
DFM
object Form21: TForm21
Left = 0
Top = 0
Caption = 'Form21'
ClientHeight = 441
ClientWidth = 644
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
OnCloseQuery = FormCloseQuery
PixelsPerInch = 96
TextHeight = 13
object Panel1: TPanel
Left = 0
Top = 0
Width = 644
Height = 384
Align = alClient
Caption = 'Panel1'
TabOrder = 0
object VideoWindow1: TVideoWindow
Left = 1
Top = 1
Width = 642
Height = 382
Mode = vmVMR
FilterGraph = FilterGraph1
VMROptions.Mode = vmrWindowed
Color = clWhite
Align = alClient
end
end
object Panel2: TPanel
Left = 0
Top = 384
Width = 644
Height = 57
Align = alBottom
Caption = 'Panel2'
TabOrder = 1
object Button1: TButton
Left = 24
Top = 16
Width = 75
Height = 25
Caption = 'Play'
TabOrder = 0
OnClick = Button1Click
end
object Button2: TButton
Left = 128
Top = 16
Width = 75
Height = 25
Caption = 'Stop'
TabOrder = 1
OnClick = Button2Click
end
end
object FilterGraph1: TFilterGraph
GraphEdit = True
LinearVolume = True
Left = 424
Top = 144
end
object OpenDialog1: TOpenDialog
Left = 344
Top = 128
end
end

Answer 1

There is no built in support for seamless looping. Yes you certainly can receive completion event, seek playback to the beginning and run the graph again, however this would inevitably have a restart delay and possibly flickering.
To implement seamless looping you either a multigraph solution, to restart upstream graph while presentation graph is on a short pause and does not flicker. Or otherwise add custom filters into the pipeline to restart streaming internally and present it as continuous stream.