Fix figures and add intro figure

010_Introduction/Introduction.tex

@@ -22,17 +22,6 @@ Similar to its predecessor, \ac{hevc} is a block-based hybrid video codec using
 The coding flexibility and efficiency of \ac{hevc}, results from the use of new coding tools and block structures, which enables new block partitions\cite{HEVCBlock2012}, improved prediction modes \cite{IntraCodingHEVC2012,AMPCodingHEVCJun2012} and new high-level  features~\cite{HEVCHighLevelReferenceDez2012}, such as explicit reference picture management and new parameter sets. 
 However, it is known that higher coding efficiency leads to lower robustness to transmission errors and data loss.
 Therefore, the new coding tools in \ac{hevc} bring not only high compression efficiency~\cite{HEVCComparisonDec2012}, but also some other disadvantages, such as increased complexity~\cite{PerformanceComplexityDez2012} and inherent reduction in error robustness.
-
-\begin{figure}[tb]
-\centering
-%\includegraphics[width=0.5\columnwidth]{./010_Introduction/HEVCTransmissionStack}
-%\includegraphics[width=0.7\columnwidth]{./010_Introduction/HEVCTransmissionStackOverview}
-%\caption{System layer stack compatible with \ac{hevc}  video transmission~\cite{HEVCLayerIntegrationDez2012}.}
-\input{./010_Introduction/RobustVideoSystem.tikz}
-\caption{Generalised diagram of a robust video transmission system.}
-\label{fig:HEVCStack}
-\end{figure}
-
 %\cite{StudyHEVCErrorsDez2012}
 Earlier studies about the error robustness characteristics of \ac{hevc} have shown that in general the use of high efficiency coding tools results in poor error resilience performance, in comparison with previous standards.
 Thus, when \ac{hevc} streams incur in transmission losses, this leads to significant degradation of both objective and subjective quality~\cite{QoEHEVCMay2014,SubjectiveEvalSep2013}.
@@ -62,9 +51,15 @@ the overall error robustness of video transmission may also benefit from the inc
 %follows.
 
 
-
+\begin{figure}[tb]
+    \centering
+    \input{./010_Introduction/RobustVideoSystem.tikz}
+    \caption{Generalised diagram of a robust video transmission system.}
+    \label{FIG1:RobustVideoTransmission}
+\end{figure}
 
 In summary, increasing the error robustness of the highly compressed video streams is a relevant research problem whose solutions will be useful to increase the adaptability for transmission diverse network conditions and to achieve robust communications in order to provide acceptable levels of \ac{qoe} to the end users at all times.
+In general, increased error robustness in video transmission can be jointly achieved at three different stages: (i) using robust video encoding, by selecting robust coding modes, (ii) after encoding, by adding robust features to the compressed streams as side-information and (iii) using robust video decoding techniques, e.g., efficient \ac{ec}. This is exemplified in Figure~\ref{FIG1:RobustVideoTransmission} where at the encoder different layer are used to increase the error robustness, which results in a video stream composed by a \ac{vcl} and \ac{sei} layers. Finally, at the decoder two processing layers are used to achieve robust video decoding.
 The \ac{hevc} reference codec is continuously being improved and extended  development by multiple proponents from around the world, also addressing the problem of error resilience and robust delivered transmission
 Although the \ac{ec} methods have been developed during the past years for \ac{h264}~\cite{2DRecursiveRefinement2010} and recently for \ac{hevc}~\cite{HEVCMCBlockAug2013}, a combined and optimised approach between encoder and decoder is yet to be developed, which would improve the users’ \ac{qoe} by exploiting shared information between the encoder and the decoder sides.