\usetikzlibrary{calc,trees,positioning,arrows,chains,shapes.geometric,%
decorations.pathreplacing,decorations.pathmorphing,shapes,%
matrix,shapes.symbols,plotmarks,decorations.markings,shadows,backgrounds}

\def\MVE{\mbox{MVE}}
\def\MVBASE{\mbox{BASE\_MC}}
\def\INTERVIEW{\mbox{INTERVIEW\_COPY}}
\def\COMBMC{\mbox{COMB\_MC}}
\def\COMBMCDISP{\mbox{COMB\_MC\_Disp}}

\newcommand{\scale}{0.4}

% Define block styles
% \tikzstyle{simple_block} = 	[rectangle,	text width=1.4cm, 	text centered, 	minimum height=1cm,node distance = 1.7cm]
% \tikzstyle{block} = 	[simple_block,draw,fill=gray!10]
% \tikzstyle{node_circle} = 	[circle, draw, 	text centered]
%
% \tikzstyle{decision} = 	[diamond, 	draw,	text centered, 	node distance=3cm]
% \tikzstyle{line} = 		[draw, -latex', thick]


\def\scale{1}




\begin{tikzpicture}[
  font=\footnotesize,
  auto,
  every node/.style={scale=\scale},
  template/.style={thick, text centered},
  block/.style={template, draw,fill=TikZColorFill, rectangle, text width=2.2cm, text centered, minimum height=.9cm, node distance=1cm},
  labels/.style={template, scale=1.2},
  line/.style={template, draw, -latex', thick},
  point/.style={template, draw, fill=black, circle,inner sep=0, minimum size=3}
]

\tikzset{
    between/.style args={#1 and #2}{
         at = ($(#1)!0.5!(#2)$)
    }
}


\node [block]                 (BMVE) {Block-based \\ MVE};
\node [block, right=of BMVE]  (PMVE) {Pixel-based \\ MVE};
\node [block, right=of PMVE]  (MVE)  {MVE};
\node [block, right=of MVE]   (MC)   {MC};

\node[coordinate, yshift=1cm, between=BMVE and PMVE] (p1) {};
\node[coordinate, yshift=1cm, between=MVE and MC] (p2) {};

\node [block, above=.6cm of p1, text width=3.7cm] (MotionEst) {Optical flow estimation};
\path [line] (MotionEst) |- (BMVE |- p1) -- (BMVE);
\path [line] (MotionEst) |- (PMVE |- p1) -- (PMVE);


\node [block, text width=2cm] at (MotionEst -| p2) (MotionExtraction) {MV parser};
\path [line] (MotionExtraction)  |- (MVE |- p2)  -- (MVE);
\path [line] (MotionExtraction) |- (MC |- p2) -- (MC);

\node[above=0cm of p2, xshift=.3cm] {$v_{-1}$};

\node[coordinate, between=PMVE and MVE] (p3) {};
\node[labels,above=3.4 of p3] (FTM1) {$f_{-1}$};
\node[labels] at (FTM1 -| MotionEst.140) (FTM2) {$f_{-2}$};


\path [line] (FTM2) -- (MotionEst.140);
\path [line] (FTM1) -- ($(FTM1 |- MotionExtraction)+(0,1)$) -| (MotionEst.40);
\path [line] (FTM1) -- ($(FTM1 |- MotionExtraction)+(0,1)$) -| (MotionExtraction.north);



\newcommand{\MDistance}{.6cm}
\node [below=\MDistance of BMVE] (M1) {M1};
\path [line] (BMVE) -- (M1);
\node [below=\MDistance of PMVE] (M2) {M2};
\path [line] (PMVE) -- (M2);
\node [below=\MDistance of MVE] (M3) {M3};
\path [line] (MVE) -- (M3);
\node [below=\MDistance of MC] (M4) {M4};
\path [line] (MC) -- (M4);



% 	\path   (BMVE.west) -- (MC.east)  node[pos=0.5] (p2) {};
%  	\node [block,  below of=p2, text width=7.5cm,node distance=1.8cm] (Select) {Concealment method selection and signalling};

% 	\path[line] (BMVE.south) -- (Select.north -| BMVE);
% 	\path[line] (PMVE.south) -- (Select.north -| PMVE);
% 	\path[line] (MVE.south) -- (Select.north -| MVE);
% 	\path[line] (MC.south) -- (Select.north -| MC);


\end{tikzpicture}