\usetikzlibrary{arrows,matrix}
\usetikzlibrary{fit}
\usetikzlibrary{intersections}

\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}
\pgfsetlayers{background,main,foreground}


\def\scale{1}


\begin{tikzpicture}[
  font=\scriptsize,
  auto,
  node distance=1cm,
  scale=\scale,
  every node/.style={scale=\scale},
  template/.style={thick, text centered},
  block/.style={template, rectangle, text width=1.3cm, ,inner sep=3, minimum height=.6cm},
  arrow/.style={template, draw, -latex},
  point/.style={template, draw, fill=black, circle,inner sep=0, minimum size=3}
]

% Define extra block styles
\tikzstyle{sumBlock}        = [template, draw, circle, inner sep=0cm, minimum size=0.3cm]
\tikzstyle{refBlockNoDraw}  = [block, fill=TikZColorFill]
\tikzstyle{refBlock}        = [refBlockNoDraw, draw]
\tikzstyle{propBlockNoDraw} = [block, fill=TikZColorFillProp]
\tikzstyle{propBlock}       = [propBlockNoDraw,draw]


\tikzstyle{MainArrow}       = [arrow]
\tikzstyle{SignallArrow}    = [arrow, dashed]


%% Encoder/Decoder
\node [refBlock, text width=1.6cm, minimum height=1cm] (Encoder) at (0,0) {Reference \\ Encoder};

%% RPS
\node [propBlockNoDraw, text width=2.6cm, minimum height=1cm, right=.3 of Encoder, yshift=1.3cm] (EXP) {Reference Selection \\ Transcoding};
\node [refBlockNoDraw, text width=2.6cm, above=-0.03 of EXP.north west, anchor=south west] (RPSDec) {Decoder};
\path[MainArrow,-] (EXP.south west) |- (RPSDec.north east) |- (EXP.south west);
\path[MainArrow,-,densely dotted] (EXP.north west) -- (EXP.north east); % Draw inside lines
\path[MainArrow] (Encoder -| EXP) node[point] {} -- (EXP);



%% NALU Loss and EC optimisation
\node [propBlock, above=.8 of RPSDec, text width=2.6cm, minimum height=2cm] (ConcOpt) {Loss simulation \\ \& \\ Saliency-weighted EC Optimisation};
\path[MainArrow] (RPSDec) -- (ConcOpt);

\node [propBlock, right=of ConcOpt.north east, anchor=north west, text width=1.6cm] (Scalable0) {EL Encoder \\(20\%)};
\node [propBlock, right=of ConcOpt.south east, anchor=south west, text width=1.6cm] (Scalable1) {EL Encoder \\(10\%)};

\path[MainArrow] (ConcOpt.east |- Scalable0) -- (Scalable0);
\path[MainArrow] (ConcOpt.east |- Scalable1) -- (Scalable1);


\node [propBlock, minimum height=.8cm, text width=2cm, right=2 of Encoder, yshift=-1cm] (StreamParser) {Stream Parser};
\path[MainArrow] (Encoder -| StreamParser) node[point] {} -- (StreamParser);

\node [propBlock, minimum height=.8cm, text width=2cm, below=.3 of StreamParser] (VideoParser) {Video analyser};

\node[text width=.7cm, text centered] (Input) at (-2,5) {Input video};


\path[MainArrow] (Input |- Encoder) node[point] {} |- (VideoParser);
\path[MainArrow] (Input) |-  (Encoder);
\path[MainArrow] (Input |- EXP) node[point] {} |-  (EXP);
\path[MainArrow] (Input |- ConcOpt) node[point] {} --  (ConcOpt);


% Mux and output
\path (Encoder.south) -- (Encoder |- ConcOpt.north) node[midway] (middleRef) {}; % Find middle ref
\node [propBlock, right=9 of middleRef, text width=5.5cm, rotate=-90, anchor=center, minimum height=1.1cm] (Mux) {Optimal stream selection};
\node [right of=Mux, node distance=2.8cm, coordinate] (Out) {};

\tikzstyle{OutputLabels}  = [pos=1, anchor=south east, text width=2cm, align=right]

\path[MainArrow] (Encoder)               --    (Mux.south |- Encoder)      node[OutputLabels] {\SMEC};
\path[MainArrow] (EXP)                   --    (Mux.south |- EXP)          node[OutputLabels] {\SMEXP};
\path[MainArrow] (Scalable1)             --    (Mux.south |- Scalable1)    node[OutputLabels] {\SMEXPELTEN};
\path[MainArrow] (Scalable0)             --    (Mux.south |- Scalable0)    node[OutputLabels] {\SMEXPELTWEN};
\path[MainArrow] (Mux)                   --    (Out)                       node[above, midway, text width=2cm, text centered] {Optimal \\ Robust Steam};

\node [text centered, text width=1.5cm, minimum height=1cm, below=.3 of Mux.east, xshift=1.9cm] (Channel) {Channel Conditions};


\path[SignallArrow] (StreamParser)  -| (Mux.-6) node (b1)                [pos=.3, anchor=center] {\footnotesize /} node[right=-.2 of b1, yshift=-6, inner sep=0] {\footnotesize 3};
\path[SignallArrow] (VideoParser)   -| (Mux.0)  node (b2) at( b1 |- VideoParser) [anchor=center] {\footnotesize /} node[right=-.2 of b2, yshift=-6, inner sep=0] {\footnotesize 2};
\path[SignallArrow] (Channel)       -| (Mux.6);

\end{tikzpicture}