Annotated interactive non-linear videos normally demand a two-stage authoring process. The structure of the video is defined in the first step, where video scenes are arranged in a scene graph. Additional information (annotations) are added to the scenes in a second step. Therefore a timeline-based editor has to be opened which enables the author to add images, videos, audio files, or text to a selected scene. User tests showed that users do not find the entry point to the annotation editor currently placed as a button on a scene in the scenegraph. This work proposes solutions for a better and more intuitive workflow in the tool to add annotations to scenes.
INTRODUCTION Annotated interactive non-linear videos consist of video scenes which are linked with each other in a scene graph. Each scene or the whole video can be extended with annotations (text, images, audio, or videos) which may add additional information to the video contents. These videos are for example very well suited for sports or physiotherapy training videos. They can furthermore be used for e-learning or tours through cities. The creation of this type of video comprises a series of steps in the authoring process. First, scenes need to be created and linked with each other in a scene graph. Then the annotations have to be linked either to single scenes (local annotation) or to the whole annotated interactive non-linear video (global annotation). Global annotations are shown during the whole playback while local annotations are faded in and out during single scenes. This affords a two-stage authoring process, whereby the navigational structure of the annotated interactive non-linear video is created first. In the second step, annotations are added.
RELATED WORK
Annotated interactive non-linear videos can be seen as a
subset of hypervideos (for an example definition see Chambel et
al. [
USER EVALUATION
Based on the knowledge that the button to add an
annotation to a scene in the scene graph is rarely found, we
conducted a user test combined with think-aloud protocols ([
Group A eventually found the entries to open the editor for the global annotations in the menu or the toolbar and was able to add the annotation to the whole video. Based on the knowledge that annotations can be added this way, they tried adding the local annotation the same way. Nine out of ten users were not able to open the annotation editor for local annotations, because they did not find the button on the scene in the scene graph. Group B also started searching in the menu or the toolbar even without the knowledge of where to add a global annotation. In this group eight out of ten users did not find the button.
Taking a look at the search areas, two groups of users could be recognized: those who did understand the connection between scenes and local annotations, and those who did not. Some users tried more than one way of opening the editor. Thereby we counted each attempt. Nine users did not realize the connection between scenes and local annotations and wanted to open the editor via the menu. Six users searched for a button in the toolbar. Seven users recognized that a local annotation has to be added to a scene and tried a right-click on the scene and started searching in the appearing menu. Five users tried a double-click on the scene. Only three users were able to open the editor without help.
TOWARDS A SOLUTION
The user test showed us the areas where users are searching
for the button to add a local annotation to a scene. If the
editor should be startable from the menu, a second step where
the scene is selected is needed. Based on the results of the
user test described in the previous section, we created a
questionnaire [
Open a pop-up with a drop-down box to select a scene.
Except selecting the scene in the annotation editor, each of the ways to select the scene to be edited can be combined with each of the ways to place the button to open the annotation editor:
Entry in the right-click menu of a scene (see Figure 2). Different questions including control questions were asked for each of the six solutions. Furthermore, pairs out of the three solutions for each problem were opposed and the preference for one solution was asked for each pair. As a result for the selection of the scene to which the annotation should be added, the pop-up with the drop-down box was not considered as useful. Marking a scene with the mouse or selecting the scene after opening the annotation editor was regarded useful. Regarding the placement of the button, the entry in the menu was not regarded useful. In contrast, using the a rightclick menu of the scene was considered useful compared to each other placement of the button.
CONCLUSION Based on the two-stage authoring process of interactive nonlinear videos, we faced the problem that authors were able to create a scene graph in the SIVA Producer, but did not find the entry point for opening the editor to add annotations to a single scene. In this work, we have proposed three methods of selecting a scene to which an annotation should be added as well as three placements of the button which opens the annotation editor. The most suitable solution according to the conducted questionnaire was an entry in the right-click menu of the scene to which the annotation should be added. Our future work includes the implementation of the proposed solution as well as further user tests to confirm the results of the questionnaire.