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


\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}
\pgfdeclarelayer{L0}
\pgfdeclarelayer{L1}
\pgfdeclarelayer{L2}
\pgfdeclarelayer{L3}
\pgfsetlayers{background,L0,L1,L2,L3,main,foreground}

\def\NodesSpacing{-1.6}
\newcommand{\scale}{.8}

\begin{tikzpicture}[scale=\scale,on grid, ->,>=stealth']

\tikzstyle{TextStyle}=[scale=.7,text centered]

\begin{scope}[scale=0.4]

  \definecolor{LCUFill}{rgb}{0,0.5,1}
  \definecolor{DrawColor}{rgb}{0,0,0.5}
  \definecolor{LCUFill}{rgb}{1,1,1}
  \definecolor{DrawColor}{rgb}{0,0,0}

  \tikzstyle{CTU}=[draw=DrawColor, fill=LCUFill, very thick]
  \tikzstyle{CU}=[draw=DrawColor, thin]
  \tikzstyle{PU}=[draw=DrawColor, thin, densely dashed]

  \node[TextStyle] at (8,16.5) {CTU - $64\times64$};
  \draw[CTU] (0,0) rectangle ++(16,16);  	% 64x64

  %% 32x32
  \draw[CU]  (0,0) rectangle ++(8,8);			% 32x32
  \draw[CU]  (8,8) rectangle ++(8,8);			% 32x32

  %% Q1
  \draw[CU]  (0,8) rectangle ++(4,4);			% 16x16
  \draw[CU]  (4,12) rectangle ++(4,4);	  % 16x16
  \draw[CU]  (4,12) rectangle ++(2,2);			% 8x8
  \draw[CU]  (6,14) rectangle ++(2,2);			% 8x8

  %% Q3
  \draw[CU]  (0,0) rectangle ++(4,4);			% 16x16
  \draw[CU]  (4,4) rectangle ++(4,4);			% 16x16
  \draw[CU]  (4,4) rectangle ++(2,2);			% 8x8
  \draw[CU]  (6,6) rectangle ++(2,2);			% 8x8

  \draw[PU]  (4,4) rectangle ++(1,1);			% 4x4
  \draw[PU]  (5,5) rectangle ++(1,1);			% 4x4

  \node[TextStyle] at (12,12) {$32\times32$};
  \node[TextStyle] at (2,14) {$16\times16$};
  \node[TextStyle,scale=.9] at (5,13) {$8\times8$};

  \node[TextStyle] (CULabel) at (9.5,6) {CU};
  \draw[black, -latex] (CULabel) to (7,7);

  \node[TextStyle] (PULabel) at (2.5,5.5) {PU};
  \draw[black, -latex] (PULabel) to (4.5,4.5);
\end{scope}

% 	%H.264
% 	\node[TextStyle] (PULabel) at (10.5,4.5) {\textcolor{red}{MB}};
% 	\draw[black, -latex] (PULabel) to (13,3);
% 	\draw[CU, draw=red]  (12,0) rectangle ++(4,4);			% 16x16
% 	\draw[CU, draw=red]  (14,0) rectangle ++(2,2);								% 8x8
% 	\draw[CU, draw=red]  (12,2) rectangle ++(2,2);								% 8x8
% 	\draw[CU, draw=red]  (15,0) rectangle ++(1,1);								% 4x4
% 	\draw[CU, draw=red]  (14,1) rectangle ++(1,1);								% 4x4

\tikzset{
  level 1/.style={level distance = 1.6cm, sibling distance=1.6cm},
  level 2/.style={level distance = 1.6cm, sibling distance=.7cm},
  level 3/.style={level distance = 1.6cm, sibling distance=.65cm},
  treenode/.style = {align=center, inner sep=0pt, text centered, font=\sffamily},
  node_split/.style = {treenode, circle,inner sep=1pt, white, font=\sffamily\bfseries, draw=black, fill=black},
  node_cu/.style = {treenode, circle, draw, thick, font=\sffamily\bfseries\scriptsize, text width=.95em}
}
\begin{scope}[xshift=12cm,yshift=15*.4cm]
  \node [node_split,scale=1/\scale]  (CUD0) at (0,0) {}
  child{ node [node_split] {}
    child{ node [node_cu] {1} }
    child{ node [node_split] {}
      child{ node [node_cu] {2} }
      child{ node [node_cu] {3} }
      child{ node [node_cu] {4} }
      child{ node [node_cu] {5} }
    }
    child{ node [node_cu] {6} }
    child{ node [node_cu] {7} }
  }
  child{ node [node_cu] {8} }
  child{ node [node_split] {}
    child{ node [node_cu] {9} }
    child{ node [node_split] {}
      child{ node [node_cu] {10} }
      child{ node [node_cu] {11} }
      child{ node [node_cu] {12} }
      child{ node [node_cu] (CUD3) {13} }
    }
    child{ node [node_cu] {14} }
    child{ node [node_cu] (CUD2) {15} }
  }
  child{ node [node_cu] (CUD1) {16} }
  ;


  \node[TextStyle, right=3.5 of CUD0] (D0) {Depth 0};
  \node[TextStyle] (D1) at (D0 |- CUD1) {Depth 1};
  \node[TextStyle] (D2) at (D0 |- CUD2) {Depth 2};
  \node[TextStyle] (D3) at (D0 |- CUD3) {Depth 3};

  \foreach \name / \y in {0,...,3}
    \node[coordinate, left=1 of D\name] (P-\name) {};
  \foreach \name / \y in {0,...,3}
    \path[draw, -] (D\name) -- (P-\name);



\end{scope}
\end{tikzpicture}