We propose an application layer algorithm for content-aware adaptive video frame scheduling on bandwidth varying channels. The proposed approach includes an iterative algorithm which sequentially uses the rate constraint and delay constraint for video frames to arrive at a decision to drop/ send video frames. In addition to our base algorithm, we also propose an explicit deadline adjustment (EDA) algorithm. The main idea behind EDA relates to the sender adjusting/ postponing the deadline of an important frame which is estimated to miss its deadline by actively dropping one (or more) less important next frame(s) and sending the deadline adjusted/ postponed frame to be displayed in place of the next dropped frame(s). The rate-distortion (R-D) performance of our proposed approach and its comparison with prior art method is shown.

In this paper, we present the design and development of a real-time interactive virtual classroom multimedia distance learning system at the University of Washington. There has been rapid progress in digital media compression research, and the delivery of media data on the public Internet is becoming widespread. A real-time interactive virtual classroom allows a remote participant to not only receive a live class feed, but also to interact in a live class by asking questions with audio, video in real-time using an Internet connection. Many instructors use electronically prepared slides during their class. The traditional video coding algorithms are not able to compress this slide data very well at low bit-rates. We propose a Web-based real-time presentation system for the electronic slides. Instructors also write text on a white board or a piece of paper during the class. At low bit-rates, conventional video encoding algorithms cannot encode this handwritten text video with enough fidelity, resulting in an illegible decoded video. We propose an extension of the well known bilevel image encoding algorithms to handle the handwritten text video. Our method results in decoded video frames which can be read very clearly when encoded at low bit-rates. We have developed a set of tools which allows recording the live classroom session and automatic creation of a synchronized multimedia integration language (SMIL) presentation, which can be used for a later viewing.

We present the design and the development of a real-time interactive virtual classroom. There has been rapid progress in digital media compression research and the delivery of media data on the public Internet is becoming widespread. A real-time interactive virtual classroom allows a remote participant not only to receive a live class feed but also to interact in a live class by asking questions. Many instructors use electronically prepared slides during their class. The traditional video coding algorithms are not able to compress this slide data very well at low bit rate. We propose a Web-based real-time presentation system for the electronic slides. Instructors also write text on a white board or a piece of paper during the class. At low bit rate, the conventional video encoding algorithms cannot encode this handwritten text video with enough fidelity, resulting in an illegible decoded video. We propose an extension of the well known bi-level image encoding algorithms to handle the handwritten text video. Our method results in decoded video frames which can be read very clearly when encoded at low bit rate.

We present a new fast motion estimation method useful for high speed video encoding. Most of the motion estimation methods for video coding can be classified as block matching (BM) methods or pel recursive (PR) methods. The majority of the current fast motion estimation methods belong to block matching category. These methods try to reduce the number of search locations. Our proposed method is based on the pel recursive formulation. However, in order to achieve fast estimation, we operate on a block of pixels using a total least squares (TLS) based estimation scheme which tries to estimate the true motion vector for each block. The major advantages of the proposed method include very fast estimation, almost constant time for motion estimation for all the video sequences, fractional pel accuracy, and better performance for noisy sequences. We present extensive simulation results to illustrate the performance of the proposed method.

The rapid evolution of communication technologies, contributed by the advanced data networks, which enable the integration of multimedia information processing and have greatly impacted our approach to distance learning. Several new multimedia features are developed and reported in this paper. These features allow students to browse the lecture contents directly on digital video sequences while also providing access to multimedia information like lecture captions, databases or handbooks with additional information or another video sequence to explain the current contents. Using these multimedia features, students can learn the course more effectively as compared to learning from conventional analog media in the distance learning environments.

The rapid evolution of communication technologies, contributed by the advanced data networks and the integration of multimedia information processing, has greatly impacted our approach to distance learning. Most existing research work emphasizes the communication aspects of multimedia roles in distance learning [3, 4]. On the other hand, we are initiating a new multimedia research activity which emphasises the development of tools for creating constructive multimedia features for course-on-demand in distance learning. In this research, we investigated the development of a course-on-demand system which allows students to access a multimedia database containing recorded video courses over various mechanisms, such as TCP/IP LANs, PSTN, and ISDN. The system is based on a client-server model. The recorded courses are stored in the server which allows multiple clients to simultaneously access the multimedia database over the networks. Students can access these pre-recorded sequences through Web browsers (e.g., Netscape, Mosaic, and Microsoft Internet Explorer) by clicking on the specific course numbers (e.g., EE440, EE505, etc) or on the specific contents (e.g., Z-transform, FIR Filters, etc). To help course instructors to create this multimedia features we have developed a hyper video editor tool. This tool allows instructor to mark various portions of the class video and create the corresponding hyper links and multimedia features by editing on line forms.