The Continuous Media (CM) Player is a tcl/tk application that supports playback of live digital audio and video on a Unix workstation. The current implementation uses a Parallax Xvideo framebuffer [1] with JPEG image decompression hardware [2]. The recorded video and audio (CM data) is stored on a file server and delivered to the application using a protocol based on UDP [3]. In keeping with the tcl/tk philosophy, the system takes a “toolkit” approach: it is designed to allow other media types, such as animation and scientific visualization, to be added into the system. This abstract describes the CM Player and the modifications we made to the Tcl/tk toolkit to implement it.

An id server can be built using Tcl-DP. The Tcl code shown in Figure 1a initializes the id server. The MakeRPCServer call of Figure 1a creates a socket on port 4545 that will accept client connections. A socket is an endpoint of network communication in UNIX [5]. The Tcl code for client processes is shown in Figure 1b. The MakeRPCClient call of Figure 1b connects to the id server and returns a handle to represent a socket. In line 2 of Figure 1b, theRPC call retrieves an unique id from the id server, by remotely invoking theGetId procedure defined in line 3 of Figure 1a.

The Daedalus experiment seeks to evaluate neutrino scattering effects that go beyond the standard model. Modular accelerators are employed to produce 800 MeV proton beams at the megawatt power level directed toward a target, producing neutrinos. The Superconducting Ring Cyclotron (SRC) consists of identical sectors (currently 6) of superconducting dipole magnets with iron return frames. The Daedalus Collaboration has produced a conceptual design for the magnet, which, after several iterations, is the current best design that achieves the physics requirements of the experiment. The Technology and Engineering Division (T ED) of the MIT Plasma Science and Fusion Center was awarded with a contract by the Daedalus team to further develop the magnet conceptual design. The resulting Engineering Study is reported here.

PICASSO is a graphical user interface development system that includes an interface toolkit and an application framework. The application framework provides high-level abstractions including modal dialog boxes and non-modal frames and panels that simplify the development of GUI applications. These abstractions can be used to define objects that are similar to conventional programming language procedures and co-routines. A library system is provided to support the development and reuse of framework objects. The framework also has a constraint system that is used to bind program variables to widgets, to implement triggered behaviors, and to implement multiple views of data. The system is implemented in Common Lisp using the Common Lisp Object System and the CLX interface to the X Window System.

This article reprises the description of the Berkeley software-only MPEG-1 video decoder originally published in the proceedings of the 1st International ACM Conference on Multimedia in 1993. The software subsequently became widely used in a variety of research systems and commercial products. Its main impact was to provide a platform for experimenting with streaming compressed video and to expose the strengths and weaknesses of software-only video decoding using general purpose computing architectures. This article compares the original performance results with experiments run on a modern processor to demonstrate the gains of processing power in the past ten years relative to this specific application and discusses the history of MPEG-1 video software decoding and the Berkeley MPEG research group.

The design and implementation of a continuous media player for Unix workstations is described. The player can play synchronized digital video and audio read from a file server. The system architecture and results of preliminary performance experiments are presented.

The Levitated Dipole Experiment (LDX) is an Innovative approach to explore the magnetic confinement of fusion plasmas. A superconducting solenoid (floating coil) Is magnetically levitated for up to 8 hours in the center of a 5-meter diameter vacuum vessel. This foil is supported by a Levitating Coil (L-Coil) on top of the vacuum vessel. In the initial machine design, this Levitating Coil was a water-cooled copper solenoid, and was the experiment's single largest load on the available water system. The main benefit of using a high temperature superconducting coil is the ability to apply more auxiliary heating power to the plasma. However, this coil will also be the first high temperature superconducting coil to be used in a US fusion program experiment. The high temperature superconducting L-Coil is a solenoid, using a two-in-hand winding of a commercially available 0.17 mm x 3.1 mm tape by American Superconductor Corporation with a critical current of 62 A st 77 K and sell-field. The L-Coil will be operated at 0.9 T and 20 K. The L-Coil has a protection circuit that not only protects it against overheating in the event of quench, but also against F-Coil collision in the event of a control failure.

The charging coil (C-coil) for the joint Columbia University/MIT Levitated Dipole Experiment (LDX) is under development jointly by MIT and the Efremov Institute. The NbTi superconducting C-coil serves to charge/discharge inductively the floating superconducting magnet to/from 2277 A when it is resting in the charging port at the bottom of the LDX vacuum vessel. The C-coil is designed for 3200 charge-discharge cycles. The solenoid magnet is installed in a low heat leak liquid helium cryostat with a warm bore of more than 1 m. The magnet protection system has an external dump resistor, which dissipates most of the 12 MJ stored during a quench.

The Maglifter is an electromagnetic catapult being considered by NASA to reduce the cost of lifting a payload into space. The system would accelerate a vehicle of up to 590 tonnes to a final velocity of 268 m/s at an acceleration of 2 g. Superconducting coils are considered for levitation because they permit track-to-vehicle clearances of more than 95 mm. The high clearances reduce tolerances and maintenance costs, and allow a system with permanently deployed wheels for take- off and emergency landing. Cable-in-conduit conductors (CICC) were selected because of their high electrical and mechanical strength, as well as high energy margin for stability. The selected coil shape is a pair of racetrack coils forming a module with four modules on a sled. The superconducting levitation modules weigh about 4% of the gross lift off weight and are capable of achieving lift off at about 20 m/s. The maximum magnetic drag power is negligible compared to the power required for acceleration.

Treating the network as a processor that can perform computation has several benefits. Processing at strategic locations in the network may reduce bandwidth requirements. Low-powered devices that are connected to the Internet can be off-loaded as well. In this paper we present Degas, a programmable media gateway system. Degas allows users to upload small programs, called deglets, into a Degas gateway to filter, transform or mix video streams from a multicast session. We describe a declarative, event-driven programming model for writing deglets. We also discuss a simple mechanism used by gateways to optimize and execute the operations specified in the deglets. Finally, a method for selecting a suitable gateway to run deglets is outlined.

This paper describes MiddleMan, a collection of cooperating proxy servers connected by a local area network (LAN). MiddleMan differs from existing proxy research in that it concentrates exclusively on video. Other approaches are optimized for HTML documents and images. MiddleMan offers several advantages. By caching videos near clients, MiddleMan reduces start-up delays and the possibility of adverse Internet conditions disrupting video play-back. Additionally, MiddleMan reduces server load by intercepting a large fraction of server accesses and can be easily extended to provide other services such as transcod-ing.

The Levitated Dipole Experiment (LDX) is a new, innovative magnetic confinement fusion experiment being designed and installed in collaboration with Columbia University at the Massachusetts Institute of Technology (MIT). The primary objective of the experiment is to investigate the possibility of steady-state, high-beta plasma confinement with near classical transport. The main component of the experiment is a levitated cryostat with a 5.7 T Nb/sub 3/Sn superconducting magnet, housed in an Inconel high pressure helium vessel. The pressure vessel is surrounded by a large thermal mass radiation shield and an outer vacuum shell, all of which are magnetically levitated inside a much larger vacuum chamber. The cryostat, now under construction is described in this paper. The cryostat keeps the magnet temperature between 5 and 10 K during 8 hours of levitated operation.

In the Levitated Dipole Experiment (LDX), a hot plasma is formed about a levitating superconducting dipole magnet in the center of a 5 m diameter vacuum vessel. The levitated magnet is suspended magnetically during an eight hour experimental run, then lowered and recooled overnight. The floating F-coil magnet consists of a layer-wound magnet with 4 sections, designed to wrap flux lines closely about the outside of the levitated cryostat. The conductor is a niobium-tin Rutherford cable, with enough stabilizer to permit passive quench protection. Lead strips are used as thermal capacitors to slow coil heating. An optimized system of bumpers and cold-mass supports reduces heat leak into the helium vessel. Airbags catch the floating coil on quenches and faults, preventing collision with the vacuum vessel.

An implantable integrated stimulator and telemetry system has been developed. The system is capable of fulfilling the stimulus and telemetry needs of advanced functional neuromuscular stimulation (FNS) applications requiring multiple channels of stimulation and multiple channels of sensor or biopotential sensing. This system provides a command control structure, an inductive radio frequency link providing power to the implant device as well as two-way transcutaneous communication, an ASIC for decoding the command and for providing functional control within the implant, and modular circuitry providing the application specific implant functions. Biocompatible hermetic packaging, lead systems, and in-line connectors suitable for long-term implantation, provide encapsulation for the circuitry and access to the electrodes and sensors used in the application. The first implant configuration realized from this modular system is targeted for clinical implementation in persons with tetraplegia at the C6 level for restoration of hand function, using wrist position as the command control source. The implant device realized has ten channels of stimulation and telemetry used to control and sense a joint angle transducer implanted in the radio-carpal joint of the wrist. A prototype device has been fabricated and is undergoing testing in an animal.

Current video compression formats optimize for either compression or editing. For example, motion-JPEG (MJPEG) provides excellent random access and moderate overall compression, while MPEG optimizes for compression at the expense of random access. Converting from one format to another, a process called transcoding, is often desirable over the life of a video segment. This paper shows how to transcode MPEG-1 video to motion-JPEG without fully decompressing the MPEG-1 source. The described technique for compressed domain transcoding differs from previous work because it uses a new approximation approach that is optimized for software implementations. This new approach is 1.5 to 3 times faster than spatial domain transcoders and offers an additional degree of freedom: higher transcoding speeds can be obtained at the price of lower picture quality. This speed/quality trade-off is useful in many real-time applications such as off-line editing and video gateways.

This paper presents a new approach for constructing libraries for building processing-intensive multimedia software. Such software is currently constructed either “from scratch” or by using high-level libraries. We have found that the second approach produces inefficient code, while the first approach is time-consuming. We therefore designed and implemented Dali, a set of reusable, high-performance primitives and abstractions that are at an intermediate point in this design space. By decomposing common multimedia data types and operations into thin abstractions and primitives, programs written using Ball are shorter and more reusable than hand-tuned C code, yet achieve competitive performance. This paper describes the design and implementation of Dali

including the Berkeley MPEG player [6], TclProp, a data Conducting research on continuous media applications is hard, in part because it is necessary to have a complete multimedia system running to be able to evaluate changes to any component such as synchronization, network protocols, or encoding. The Berkeley Continuous Media Toolkit provides customizable support for an entire multimedia pipeline. This demonstration will illustrate several applications and research projects build using CMT while showing how CMT is used to build applications and experiment with innovative multimedia systems research.

We present a new technique for morphing two video sequences. Our approach extends still image metamorphosis techniques to video by performing motion tracking on the objects. Besides reducing the amount of user input required to morph two sequences by an order of magnitude, the additional motion information helps us to segment the image into foreground and background parts. By morphing these parts independently and overlaying the results, output quality is improved. We compare our approach to conventional motion image morphing techniques in terms of the quality of the output image and the human input required.

Jacl, Java Command Language, is a version of the Tcl [1] scripting language for the Java [2] environment. Jacl is designed to be a universal scripting language for Java: the Jacl interpreter is written completely in Java and can run on any Java Virtual Machine. Jacl can be used to create Web content or to control Java applications.This paper explains the need for Jacl as a scripting language for Java and discusses the implications of Jacl for both the Java and Tcl programming communities. It then describes how to use Jacl. It also explains the implementation of the Jacl interpreter and how to write Tcl extensions in Java.