Naohisa Ohta

Basic characteristics of variable rate video coding in ATM environment

Basic characteristics of variable-rate video coders applied to asynchronous transfer mode (ATM) transmission are described. Burstiness of video information is evaluated for conference-type scenes using various coding algorithms. Three measures (distribution, autocorrelation, and coefficient of variation) are introduced to evaluate burstiness. Video sources are modeled and characterized by the autoregressive process and coefficient of variation. Video quality improvement achieved with variable rate transmission is evaluated using signal-to-noise ratio (SNR) and subjective ratings. An improvement of 5-10 dB in temporal SNR and 1 rank in mean opinion score are reported. >

All-digital super high definition images

Abstract In this paper, we will present a survey of the all-digital super high definition (SHD) image specifications currently under development by the authors to support this type of media integration. We will discuss specification requirements, encoding and support technologies, and present a survey of signal processing systems. Especially, we will focus on the NOVI-II experimental system which was created to develop signal processing architectures for all-digital SHD image processing, as well as to evaluate compression schemes for SHD images. Of course, any discussion of media integration cannot fail to touch on hypermedia, so we will also examine the relationship of hypermedia to super high definition images.

Packet video transmission through ATM networks

The basic aspects of packet video transmission technology are described, and some new results are presented. The advantages of packet video transmission through ATM (asynchronous transfer mode) networks and items to be solved are discussed from both the network and the user sides. Modeling methods, including burstiness measures are described. Examples of modeling based on the Markov modified Poisson process are shown. Packet loss protection and recovery methods are discussed, and the effects of a layered coding scheme are described. Subjective picture quality based on variable rate video transmission is demonstrated.<<ETX>>

Real time switching and streaming transmission of uncompressed 4K motion pictures

In this paper we describe the worlds first Trans-Pacific and Trans-Atlantic real-time switching and streaming transmission of uncompressed 4K motion pictures. This demonstration, of an advanced networked media application, conveyed the 23rd Kyoto Prize events, held on Nov. 10 and 11, 2007, from Kyoto, Japan to Stockholm, Sweden in real-time with life-like image quality. Multiple live 4K streams from different cameras were switched over the network into a single uncompressed stream at the directors request, and transmitted to Stockholm via 10 Gbit Ethernet connections over 21,000 km using the Global Lambda Integrated Facility (GLIF). We introduce several new technologies, including an uncompressed 4K video streaming system using Internet Protocol (IP) transmission and a shared line approach to gap-less video switching control. The Kyoto Prize 2007 demonstration proves the feasibility of using the IP infrastructure for next generation video switching and distribution networks, even at very high speeds across great distances.

Variable rate video coding using motion-compensated DCT for asynchronous transfer mode networks

Variable-rate video-coding using a motion-compensated discrete cosine transform (DCT) and its characteristics are discussed, focusing on quality improvement and application aspects. An objective measure is proposed for quality estimation of variable-rate video coding. Subjective evaluation results, including the relationship between subjective and objective ratings, are also shown. Important points are considered with respect to the application of the coder to asynchronous transfer mode systems.<<ETX>>

Layered coding for ATM based video distribution systems

Abstract This paper discusses packet loss and its protection in an asynchronous transfer mode (ATM) based video distribution system. Packet losses in ATM based networks have such a great impact on the design of coding algorithms and network architectures that they should be exhaustively discussed and resolved. In this paper, first basic configuration of the ATM based video transmission system and its packet-loss protection schemes are discussed. The DCT based layered coding scheme with packet priority classification is proposed as an effective packet-loss protection scheme. Burstiness characteristics of the broadcast video sources are evaluated and modeled to clarify statistical multiplexing performance and packet-loss properties. The quality degradation caused by the packet losses is also evaluated by the SNR, and the superior performance of the proposed layered coding scheme is verified.

A load balancing technique for video signal processing on a multicomputer type DSP

To extract full performance from a multicomputer digital signal processing (DSP) system, the development of a viable load balancing technique is considered indispensable. The authors describe a task allocation and control methodology for image signal processing, such as is used in a low-bit rate (e.g. 64-kb/s) motion picture coding system. On a massive homogeneous multicomputer-type DSP system, the following approaches increase system performance substantially: (1) task scheduling with interframe prediction; (2) layered large-grain data flow; and (3) predefined local reassignment of processing. The effects of these various methods are examined in the context of a low bit rate motion picture codec with motion compensation and vector quantization application.<<ETX>>

Architecture and performance of a multicomputer type digital signal processing system 'NOVI'

The authors introduce a parallel DSP (digital signal processing) system called NOVI, consisting of 36 processor nodes. NOVI has a multicomputer architecture, which provides high programmability and effective scheduling capability. Its program-development-assist system facilitates powerful debugging functions to observe all states of NOVI and to control its execution. Each processor node comprises a transputer, a floating-point ALU (arithmetic logic unit), and 1 Mbyte of local memory, which can deal with even rather large tasks within a single node. An interconnection board allows easy reconfiguration into various network topologies.<<ETX>>

4K applications beyond digital cinema

4K that became a digital cinema standard in 2005 is now recognized as the next high quality image technology of HD in the market. This paper describes what 4K is, the status of 4K, and 4K applications other than digital cinema. We introduces three 4K applications, 4K alternative content with live transmission, 4K usage in dome theaters, and 4K video conference with our proof-of-concept experiments over the world.

Performance improvement technique for synchronous circuits realized as LUT-based FPGAs

This paper presents a new technique for improving the performance of a synchronous circuit configured as a look-up table based FPGA without changing the initial circuit configuration; only the register location is altered. It improves clock speed and data throughput at the expense of latency. One of the most significant benefits realized by this approach is that the time-consuming and user-uncontrollable reconfiguration processes, i.e., remapping, replacement, and rerouting, are unnecessary when improving circuit performance. After applying our technique to some benchmark circuits, the average performance improvement was 33% for six combinational circuits, and 25% for 18 sequential circuits. >