The decaying sound field in rooms is typically described by energy decay functions (EDFs). Late reverberation can deviate considerably from the ideal diffuse field, for example, in multiple connected rooms or non-uniform absorption material distributions. This paper proposes the common-slope model of late reverberation. The model describes spatial and directional late reverberation as linear combinations of exponential decays called common slopes. Its fundamental idea is that common slopes have decay times that are invariant across space and direction, while their amplitudes vary across both. We explore different approaches for determining the common slopes for large EDF sets describing different source-receiver configurations of the same environment. Among the presented approaches, the k-means clustering of decay times is the most general. Our evaluation shows that the common-slope model introduces only a small error between the modeled and the true EDF, while being considerably more compact than the traditional multi-exponential model. The amplitude variations of the common slopes yield interpretable room acoustic analyses. The common-slope model has potential applications in all fields relying on late reverberation models, such as source separation, dereverberation, echo cancellation, and parametric spatial audio rendering.

In this paper, we describe two interface designs for mobile video browsing on pen-based handheld devices. Both feature different interaction types, such as speed- and position-based navigation which enable users to interactively skim a video's content along the timeline at different granularity levels. The feasibility and usefulness of the proposed designs is demonstrated in a comparative user study.

Small screen sizes and limited interaction possibilities appear to be the main challenges when developing video browsing interfaces for mobile devices, such as smartphones and PDAs. In this demo, we present several pen-based designs for interactive video browsing on a PDA. Each implementation enables users to skim a video along the timeline at different speeds and granularity levels. Using the whole touch-sensitive screen as input area, different pen movements are mapped to different browsing behaviors, offering more functionality and creating a better user experience.

We present an interface for interactive video browsing on pen-based handheld devices. Our solution enables users to navigate through a video along the timeline at different granularity levels. In addition, one can skim a file's content by continuous modification of replay speed. Both interaction concepts are smoothly integrated into a single interface that takes full advantage of the limited screen space being available.

Today, videos can be replayed on modern handheld devices, such as multimedia cellphones and personal digital assistants (PDAs), due to significant improvements in their processing power. However, screen size remains a limiting resource making it hard, if not impossible to adapt common approaches for video browsing to such mobile devices. In this paper we propose a new interface for the pen-based navigation of videos on PDAs and multimedia cellphones. Our solution - called the MobileZoomSlider - enables users to intuitively skim a video along the timeline on different granularity levels. In addition, it allows for continuous manipulation of replay speed for browsing purposes. Both interaction concepts are seamlessly integrated into the overall interface, thus taking optimum advantage of the limited screen space. Our claims are verified with a first evaluation which proves the suitability of the overall concept.

In This work we introduce new approaches for visual information seeking in video documents. We argue that a discrete visualization of continuous media streams via static keyframes is not sufficient to fulfill all information needs and therefore additional, more interactive techniques are required. We extend the concept of elastic interfaces, which has been used successfully with discrete documents, by applying it to continuous data streams. In addition, we propose a different integration of the elastic browsing functionality called "elastic panning". A first usability test is presented in order to prove its feasibility and to highlight its main advantages, namely the ability to access any position within a file independent of its length, and the smoother visual feedback during navigation compared to a standard slider interface.

In this demonstration we present three interface designs which enable users to visually browse video data by moving a slider thumb along the timeline. In such a case, scrolling granularity is usually limited because of the fixed length of the corresponding slider. In contrast, our interaction designs enable users to skim the data at different granularity levels by providing the possibility to continuously change the slider's scale, by using a nonlinear scale, and by enabling interactive manipulation of the scrolling speed, respectively.

Today's interfaces for time-scaled audio replay have limitations especially regarding highly interactive tasks such as skimming and searching, which require quick temporary speed changes. Motivated by this shortcoming, we introduce a new interaction technique for speech skimming based on the so called rubber-band metaphor. We propose an "elastic" audio slider which is especially useful for temporary manipulation of replay speed and which integrates seamlessly into standard interface designs. The feasibility of this concept is proven by an initial user study.