DSPack ability to move to the middle of a video

Question

I have built a mediaplayer application based on the PlayWin demo that comes with DSPack. I have built this in Delphi 10.4 Sydney. The primary file type I am focussing on is *.mp4. All this is working fine.

I would like to provide the capability to move to the middle of the currently plying video and continue playing to the end of the video.

I have searched extensively on StackOverflow and attempted any solutions that appear correct. Nothing has worked.

My current attempt is:

procedure TMediaPlayer.btnMoveToMidVideoClick(Sender: TObject);
Var
  sgBefore: String;
  sgAfter: String;
  MediaSeeking: IMediaSeeking;
  Start: Int64;
  Stop: Int64;
begin
  FilterGraph.Active := true;
  VideoWindow.FilterGraph:= FilterGraph;
  FilterGraph.RenderFile('S:\iTube Studio Downloaded\6.5 HP Greyhound Engine\6_5HP_Best Way To Clean a Honda Style Carburetor - Vide0.mp4');
  FilterGraph.QueryInterface(IMediaSeeking, MediaSeeking);

  Start := 1200519 div 2;
  Stop := 1200519;

  MediaSeeking.SetPositions(Start, AM_SEEKING_AbsolutePositioning, Stop, AM_SEEKING_AbsolutePositioning);

  FilterGraph.Play;
end;

I HAVE NO IDEA WHERE TO GET THE START AND STOP VALUES FROM.

Can anyone figure out how to move to the middle of a currently playing video?

Dick Maley

Thank you in advance.

Answer 1

I thank you all for your ideas.

It can be done, Here is the code that achieved it.

Procedure TMediaPlayer.actVideoHalfWayExecute(Sender: TObject);
Var
  inThumbX: Integer;
  inThumbY: Integer;
  R: TRect;
Begin
  FillChar(R, 0, Sizeof(R));
  tbDSTrackBar.Perform(TBM_GETTHUMBRECT, 0, lparam(@r));
  inThumbX := (r.Left + r.Right) Div 2;
  inThumbY := (r.Top + r.Bottom) Div 2;
  tbDSTrackBar.MouseDown(mbLeft, [], inThumbX, inThumbY);
  tbDSTrackBar.Position := tbDSTrackBar.max Div 2;
  Application.processmessages();
  inThumbX := tbDSTrackBar.Width Div 2;
  tbDSTrackBar.MouseUp(mbLeft, [], inThumbX, inThumbY);
  Application.processmessages();
End;

However, I cheated. I modified TDSTrackBar in DSPack.pas from

  protected
    {@exclude}
    procedure Notification(AComponent: TComponent; Operation: TOperation); override;
    {@exclude}
    procedure MouseUp(Button: TMouseButton; Shift: TShiftState;
      X, Y: Integer); override;
    {@exclude}
    procedure MouseDown(Button: TMouseButton; Shift: TShiftState;
      X, Y: Integer); override;
    {@exclude}
    procedure Timer; dynamic;

To

  public
    {@exclude}
    procedure Notification(AComponent: TComponent; Operation: TOperation); override;
    {@exclude}
    procedure MouseUp(Button: TMouseButton; Shift: TShiftState;
      X, Y: Integer); override;
    {@exclude}
    procedure MouseDown(Button: TMouseButton; Shift: TShiftState;
      X, Y: Integer); override;
    {@exclude}
    procedure Timer; dynamic;

My objective was to move to the halfway point in the video and trackbar, however this code can be used to move any anywhere in the video and trackbar.

Thank you

Dick Maley