IdTCPServer1: TIdTCPServer;
    IdTCPClient1: TIdTCPClient;

procedure TForm2.IdTCPServer1Connect(AContext: TIdContext);
begin
  AContext.Connection.IOHandler.WriteFile('D:\test.avi');
  AContext.Connection.Disconnect;
end;

procedure TForm2.Button1Click(Sender: TObject);
Var
  LStream : TStream;
  sStream : TIdStreamVCL;
begin
  if not IdTCPClient1.Connected then
    IdTCPClient1.Connect;
  try
    LStream := TFileStream.Create('C:\Test_2.tst', fmCreate);
    try
      sStream := TIdStreamVCL.Create(LStream, True);
      IdTCPClient1.IOHandler.ReadStream(sStream,-1,True);
    finally
      FreeAndNil(sStream);
    end;
    Memo1.Lines.Add('Client READ');
  except
    Memo1.Lines.Add('Client error');
  end;

end;