Merge branch 'axel'

src/bib.bib

@@ -722,3 +722,12 @@
   year={2019},
   organization={ACM}
 }
+
+@inproceedings{ozcinar2017viewport,
+  title={Viewport-aware adaptive 360 video streaming using tiles for virtual reality},
+  author={Ozcinar, Cagri and De Abreu, Ana and Smolic, Aljosa},
+  booktitle={2017 IEEE International Conference on Image Processing (ICIP)},
+  pages={2174--2178},
+  year={2017},
+  organization={IEEE}
+}

src/state-of-the-art/video.tex

@@ -40,7 +40,7 @@ In fact, a representation of the images of a chapter of a movie is still a long
 
 Segments are used to prevent this issue.
 They typically encode files that contain two to ten seconds of video, and give the software a greater ability to dynamically adapt to the system.
-If a user wants to seek somewhere else in the video, only one segment of data can be lost, and only one segment of data needs to be downloaded for the playback to resume. The impact of the segment duration has been investigated in many work, including \citep{sideris2015mpeg, stohr2017sweet}. For example, \citep{stohr2017sweet} discuss how the segment duration affects the streaming: short segments lower the initial delay and provide the best stalling Quality of Experience, but make the total downloading time of the video longer because of overhead.
+If a user wants to seek somewhere else in the video, only one segment of data is potentially lost, and only one segment of data needs to be downloaded for the playback to resume. The impact of the segment duration has been investigated in many work, including \citep{sideris2015mpeg, stohr2017sweet}. For example, \citep{stohr2017sweet} discuss how the segment duration affects the streaming: short segments lower the initial delay and provide the best stalling Quality of Experience, but make the total downloading time of the video longer because of overhead.
 
 \subsubsection{Content preparation and server}
 
@@ -56,8 +56,8 @@ A client typically starts by downloading the MPD file, and then proceeds on down
 The most important part of any implementation of a DASH client is called the adaptation logic. This component takes into account a set of parameters, such as network conditions (bandwidth, throughput, for example), buffer states or segments size to derive a decision on which segments should be downloaded next. Most of the industrial actors have of course their own adaptation logic, and many more have been proposed in the literature. A thorough review is beyond the scope of this state-of-the-art, but examples include \citep{chiariotti2016online} who formulate the problem in a reinforcement learning framework, \citep{yadav2017quetra} who formulate the problem using Queuing theory, or \citep{huang2019hindsight} who use a formulation derived from the Knapsack problem. 
 
 \subsection{DASH-SRD}
-DASH has already been adopted in the setting of video streaming.
-DASH-SRD (Spatial Relationship Description,~\citep{dash-srd}) is a feature that extends the DASH standard to allow streaming only a spatial subpart of a video to a device.
+Being now widely adopted in the context of video streaming, DASH has been adapted to various other contexts.
+DASH-SRD (Spatial Relationship Description,~\citep{dash-srd}) is a feature that extends the DASH standard to allow streaming only a spatial subpart of a video to a device. 
 It works by encoding a video at multiple resolutions, and tiling the highest resolutions as shown in Figure~\ref{sota:srd-png}.
 That way, a client can choose to download either the low resolution of the whole video or higher resolutions of a subpart of the video.
 
@@ -93,7 +93,7 @@ An example of such a property is given in Listing~\ref{sota:srd-xml}.
     ]{assets/state-of-the-art/video/srd.xml}
 \end{figure}
 
-Essentially, this feature is a way of achieving view-dependent streaming, since the client only displays a part of the video and can avoid downloading content that will not be displayed.
+Essentially, this feature is a way of achieving view-dependent streaming, since the client only displays a part of the video and can avoid downloading content that will not be displayed. While Figure~\ref{sota:srd-png} illustrates how DASH-SRD can be used in the context of zoomable video streaming, the ideas developed in DASH-SRD have proven particularly useful in the context of 360 video streaming (see for example \citep{ozcinar2017viewport}).  
 This is especially interesting in the context of 3D streaming since we have this same pattern of a user viewing only a part of a content.
 
 % \subsection{Prefetching in video streaming}