WO1998033317A2

WO1998033317A2 - System and method for video/audio conferencing

Info

Publication number: WO1998033317A2
Application number: PCT/US1998/001163
Authority: WO
Inventors: Dennis M. Diresta
Original assignee: Diresta Dennis M
Priority date: 1997-01-24
Filing date: 1998-01-22
Publication date: 1998-07-30
Also published as: WO1998033317A3; AU6034798A

Abstract

A video conferencing system (11) and method is disclosed for providing real-time audio/visual communications and data transfer between at least two device/system users over conventional POTS copper-wire based telephone lines, or T1/E1 telephone lines (39). The video conferencing system includes: a personal computer (13), a combination video and audio encoding and decoding circuit, a combination video display and audio input/output circuit, a sound sensing device, a digitizing circuit for transforming detected sound into digital audio, a continuous display camera (20) in electronic communication with the input/output circuit including an overlay feature for transforming detected visual images into a digital video signal, and a two way coder/decoder (CODEC) for combining the transformed digital audio and digital video signals into high-speed digital audio/visual signals.

Description

SYSTEM AND METHOD FOR VIDEO/AUDIO CONFERENCING

FIELD OF THE INVENTION

The present invention relates to telecommunications devices and systems, and more particularly, to digital audio/video communication networks, devices and systems capable of operating at speeds up to 768 kilobits per second (Kbps) in each direction of communication via any one of a number of different transmission medias, such as high-bit-rate digital subscriber line (HDSL), Ethernet, satellite, TCP/IP Internet, token ring, or Tl/El telephone lines.

BACKGROUND OF THE INVENTION

Other devices and systems have been proposed in the prior art for audio-video conferencing. Examples of such devices can be found in he following U.S. Letters Patent: No. 5,038,224 to Martulli, et al.; No. 5,034,916 to Ordish; No. 5,027.198 to Yoshioka; No. 5,018,186 to Kumara, et al.; No. 4,931,872 to Stoddard, et al.; No. 4,928,301 to Smoot; No. 4.890,314 to Judd, et al.; No. 4,882,743 to Mahmoud; and No. 4,215,252 to Onufry. Jr. While these devices may be suitable for a particular purpose to which they address, it will be apparent to those skilled in the art that said devices would not be as suitable for the purposes of the present invention. Although these and other such devices now in the prior art have attempted to address the need for video conferencing type communication between a plurality of remote sites, they have failed to address the need for such communication to be performed at a cost which is not prohibitive. Indeed, most of such prior art teleconferencing systems fall into one of the following three categories of such systems:

1 ) Large, expensive conference room systems where the participants gather at central locations;

2) In-house, specially-wired network based systems, such as Digital Equipment Corporation's DEC SPIN; or 3) Single user products not having the capability of simultaneously communicating between more than two sites with real-time video at more than 2-3 frames per second. The expense and limitations related to such devices have prevented a more extensive use of such devices.

SUMMARY OF THE INVENTION In view of the foregoing disadvantages inherent in the known types of video conferencing devices now present in the art, the invention disclosed herein provides a PC-based video conferencing device and system for performing point-to-point or multi-user video conferencing over conventional POTS (plain old telephone service) copper-wire based lines, or Tl/El telephone lines. The video conferencing device of the present invention includes a personal computer, a combination video and audio encoding and decoding circuit, a combination video display and audio input/output circuit for combining the digital audio and digital video signals into a high speed digital audio/video signal, a channel service unit (CSU) for converting the high-speed digital audio/video signal into a Tl/El signal, and a high-bit-rate digital subscriber line (HDSL) modem for transmitting the Tl/El signal over a conventional copper- wire based telephone line. Upon a closer review of the more detailed description herein, those skilled in the art will recognize the concepts of the present invention easily overcomes the problems described about which have been heretofore commonly associated with video conferencing devices and systems. As such the general purpose of the present invention is to provide a new and improved video conferencing device and system which has all the advantages of the prior art and none of the disadvantages.

It is a further object of the present invention to provide a new and improved video conferencing device and system which can provide real-time audio/video communication over conventional copper-wire based telephone lines, or minimally enhanced fractional/full Tl/El telephone lines.

It is a further object of the present invention to provide a new and improved video conferencing device and system which can provide simultaneous real-time audio video communication between four or more remote user sites, without the use of a Multipoint Control Unit (MCU).

It is a further object of the present invention to provide a new and improved video conferencing device and system which can provide simultaneous real-time audio/video communication between a plurality of remote user sites, said communication including the ability of each site to view simultaneously on one video screen real-time motion video being transmitted from each of the other sites with which the communication is occurring. It is a further object of the present invention to provide a new and improved video conferencing device and system which can provide simultaneous real-time audio/visual communication between a plurality of user sites, said communication being performed via Tl/El wire-based telephone network.

It is a further object of the present invention to provide a new and improved video conferencing device and system which can provide real-time whiteboard data transfer simultaneous with real-time audio/visual communications, such as movies. It is a further object of the present invention to provide a new and improved video conferencing device which provides to each user a cable television network connection simultaneously for performing tasks, such as communicating or computing, with a terminal of the cable system.

It is a further object of the present invention to provide a new and improved video conferencing device which includes a means for recording selected portions of various audio/visual communications received or transmitted from the device, such that said selected portions can be viewed or retransmitted at a later time. It is a further object of the present invention to provide a new and improved video conferencing device including functionality for focusing automatically image(s) selected by the user for transmitting.

It is a further object of the present invention to provide a new and improved video conferencing device and system which meets all federal, state, local and other private standards, guidelines, regulations and recommendations with respect to safety, environmental friendliness, energy conservation, etc.

It is a further object of the present invention to provide a new and improved video conferencing device and system which can be manufactured at a low cost with regard to both materials and labor, and which accordingly is then susceptible to low prices for sale to the consuming public. Thereby, the video conferencing system of the present invention is economically available to the buying public. These, together with other objects of the invention, along with the various features of novelty which characterize the video conferencing device and system of the present invention, are pointed out with particularity in the claims appended hereto and forming part of this disclosure. The more important objects of the present invention have been outlined rather broadly in order that the detailed description which follows may be better understood, and in order that the present contribution to the art may be better appreciated. For a better understanding of the instant invention, its operational advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated various embodiments of the invention.

Those versed in the art will readily ascertain, however that the present invention is capable of other embodiments and of being practiced and carried out in various other ways. In this respect, the details of construction disclosed herein, including the component materials and the arrangements of the components set forth in the following description and appended drawings, are for illustrative purposes only, and are not intended to be limiting in scope. Those skilled in the art will appreciate, as well, that the conception upon which this disclosure is founded, may be readily utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. Said other structures may include, but are not limited to, those which are aesthetic in nature, or those which include the substitution of other materials as they become available, and which substantially perform the same function in substantially the same manner with substantially the same result as the present invention. It is important, therefore, that the claims appended hereto be regarded as including such equivalent materials, structures, constructions, methods, and systems insofar as these do not depart from the spirit and scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following drawings in conjunction with the detailed description. Further, like reference numerals designate corresponding parts throughout the several views. FIG. 1 is a block diagram of an embodiment of a video teleconferencing system according to the present invention;

FIG. 2 is a block diagram of another embodiment of a video conferencing system according to the present invention; and FIG. 3 is a block diagram of the present-invention configured with a video dial tone network.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention comprises an improved video conferencing device and system for providing real-time audio/visual communications and data transfer between at least two device/system users over conventional POTS copper-wire based telephone lines, or Tl/El telephone lines. The video conferencing device of the present invention includes: a personal computer, a combination video and audio encoding and decoding circuit in electronic communication with the personal computer, a combination video display and audio input/output circuit in electronic communication with the personal computer, a sound sensing device, such as a microphone, in electronic communication with said input/output circuit, a digitizing circuit for transforming detected sound into a digital audio signal, a continuous display camera in electronic communication with said input/output circuit including an overlay feature for transforming detected visual images into a digital video signal, and a two way coder/decoder (CODEC) for combining the transformed digital audio and digital video signals into a high-speed digital audio/visual signal. Embodiments of the video conferencing system may also include a channel service unit (CSU) for converting (i.e., inverting) the high-speed digital signals to a Tl/El signal for transmission to a high-bit-rate digital subscriber line (HDSL) modem which places the signal on conventional POTS copper-wire based telephone lines. Various embodiments of the invention are illustrated in the appended drawings and described in greater detail below.

FIG. 1 is a block diagram illustrating the electronic circuitry of an embodiment of a video conferencing system 1 1 according to the present invention. The system 11 is based on a personal computer 13, which includes various devices which are normally associated with personal computer devices of the prior art, including a central processing and control circuit, a random-access-memory storage device, readonly-memory storage device, a data input device, a video display device, and a audio output device. It is preferred that the personal computer 13 can perform normal personal computing tasks either simultaneously with a video conferencing session, or when the system 1 1 is not in video conferencing mode. In electronic communication with the personal computer 13 is a combination video/audio encoding and decoding circuit 15, for decoding electronic transmission received from other communications devices as discussed hereafter. In the instant embodiment, it is preferred that the combination video and audio encoding and decoding circuit 15 comprises a CODEC circuit board based on the AT&T Microelectronics AVPIOOO Video Codec chip set which supports Px64 type compression and decompression algorithms for full motion video. The AVP 1000 chip set includes an AVP1300E video encoder 17 that is in electronic communication with a video camera 20 and includes a video digitizing circuit (not shown) for transforming the visual images detected by the camera 20 into a digital video signal. The video encoder 17 contains a motion estimator processor that performs an exhaustive motion search for transmitting changes from the previous frame, referred to as video overlay. The video encoder 17 also provides the flexibility to adjust picture quality, encoding delay, and output frame rate. The video encoder 17 still further provides for conversion of a camera RGB signal output to the digital pixel YCbCr 4:2:2 and storage in a 1 megabits per second (Mbps) external 70 nano-second (ns) digital random access memory (DRAM).

Further included in the preferred encoding and decoding circuit 15 is an AVP1400C system controller 19, which acts as the coordinator for the AVPIOOO chip set. The system controller 19 moves pixel data from a video decoder 23 to a video overlay board 25, and further controls all the required formatting and controlling functions. The video decoder 23 is for accepting encoded data and delivering decoded YCbCr 4:2:2 pixels to the video overlay board 25 in order to drive the video input of a video display device 26, such as a color monitor. It is preferred that the video display device 26 be either a digital high resolution type monitor (i.e., 1068 x 800 pixels or 800 x 600 pixels), for providing maximum visual clarity, or a National Television Standards Committee (NTSC) or phase alternating line (PAL) compatible television monitor. Features of the decoder 23 include on-chip color conversion, 4 Kilobits per second (Kbps) buffering for storage of compressed data, 1 Mbps of 70-ns DRAM, and a direct interfacing with the controller 19. The video overlay board comprises an external frame buffer 27 and a video display driver 29. The frame buffer is preferably a 4 Mbps DRAM frame buffer with associated video controller circuitry. Such a large frame buffer is desired for simultaneously displaying multiple independent windows on the monitor. As the pixel data moves from the decoder 23 to the frame buffer 27, the video display driver 29 constantly refreshes and updates the display of the color monitor 27. Still further included in the AVPIOOO chip set of the encoding and decoding circuit 15 is an audio CODEC circuit 30 and a host microprocessor (not shown). The audio CODEC circuit 30 is for decoding and delivering audio data to the speakers 31 , and for digitizing and encoding audio signals which are detected by a microphone 33. The host microprocessor initializes and communicates with the controller 19 by reading and writing to its configuration and control registers. The encoded bit rate for the AVPIOOO chip set is selectable from 40 Kbps to 40 Mbps. A broad range of bit- rate capability, such as from 56 Kbps to 2.048 Mbps, is necessary to maintain good picture quality when transmitting over channels such as Switched 56, ISDN (integrated services digital network), Tl and the European El . A TI access controller 35 is connected to the encoding and decoding circuit 15 via a 24-pair cable 37 and is provided for switching calls to and from the encoding and decoding circuit 15 under software control. The Tl access controller 35 also converts the digital audio and digital video signals from the combination video and audio encoding and decoding circuit 15 into a high-speed digital audio/visual signal for transmission over a Tl carrier facility 39 . The Tl access controller 35 allows a plurality of calls to be displayed simultaneously and places any calls above which can be displayed simultaneously on queue for later accessing. Such an in-queue electronic bridge (similar to call waiting in that it alerts the user when another call is on the line) also allows standard audio calls to be patched into an on-going video conference. The system 11 is further capable of transmitting, receiving and displaying in a real-time mode whiteboard type data, such as spreadsheets data-bases, movies, or broadcast television. Illustrated in FIG. 2 is another embodiment of a video conferencing system 11 1 according to the present invention, which is substantially similar to the system 1 1, except as described hereafter. Like the system 11 , the system 111 is based on a personal computer 113, which includes various devices which are normally associated with personal computer devices of the prior art, including a central processing and control circuit, a random-access-memory storage device, a read-only-memory storage device, a data input device, a video-display device and an audio output device. It is preferred that the personal computer 113 include a high speed microprocessing circuit, such as the Pentium® processor by Intel Corporation, Santa Clara, CA, U.S.A.. It is also preferred that the personal computer 113 is capable of performing normal personal computing tasks in a multitasking environment either simultaneously with a video conferencing session, or when the system 1 11 is not in video conferencing mode. In electronic communication with the personal computer 113 is a combination video and audio board comprising a video/audio encoding and decoding circuit 115, for decoding electronic transmission received from other communication devices, and for encoding signals for sending to other communications devices. In the instant embodiment, it is preferred that the combination video and audio encoding and decoding circuit 115, comprise a suitable CODEC circuit board, such as Model VS1000 by Mentec, Inc., Lowell, MA, U.S.A., which uses motion estimation and echo cancellation. Such a CODEC enables the system 11 1 to provide 30 frames per second because the CODEC maintains a 640 X 480 pixels regardless of the number of conference participants.

In electronic communication with the encoding and decoding circuit 1 16 is a combination audio/video input/output circuit 121 , which is in electronic communication with a suitable combination audio/video detection unit 122, such as Model PCS-V2 by Sony Corporation of America, New York, NY, U.S.A. The input/output circuit 121 digitizes the visual and sound signals from the audio/video detection unit 122. and relays the signals to the encoding and decoding circuit 1 15. The audio/video input/output circuit 121 further includes circuitry for decoding data to the speakers 131, and for driving a video display device 126, such as an SVGA color monitor, an NTSC television monitor, or a PAL television monitor. A suitable network interface board 135, such as the V.l 1 board by Mentec, Inc.. is provided for converting the digitized audio and visual signals from the encoding and decoding circuit 1 15 into a high-speed digital audio/visual signal for transmission to a signal conversion device 139 over a 24-pair cable 137. V.l 1 is a recommended standard of electrical characteristics for balanced double-current interchange circuits for general use with integrated circuit equipment in the field of data communications, as defined by the International Telecommunications Union- Telecommunications Standard (ITU-TSS), formerly the Consultative Committee on International Telegraphy & Telephony (CCITT). It is preferred that this high speed audio/visual signal is an RS-449 signal, as defined in the publicly available standard documentation of the Electronics Industries Association (EIA). The interface board 135 allows a plurality of calls to be displayed simultaneously, and places any calls above which can be displayed simultaneously on queue for later accessing. Such an in-queue electronic bridge also allows standard audio calls to be patched into an on- going video conference,. A suitable signal conversion device 139, such as the DataSmart® channel service unit (CSU) by ADC Kentrox, is also provided for converting the RS-449 signal from the interface board 135 to a Tl/El type signal. For transmitting over conventional POTS copper- wire based telephone lines 140 connected to the PSTN, it is preferred that the signal conversion device 139 be further connected to the POTS lines 140 via a suitable high-speed modern 142 that use Carrierless Amplitude and Phase Modulation (CAP) and Discrete Multitone (DMT), such as high-bit-rate digital subscriber line (HDSL) protocol. A suitable modem 142 that utilizes HDSL is the COPPER ACCEL™ by Performance Telecom, Rochester, NY, U.S.A. It is noted that modems utilizing digital subscriber line technology typically allow POTS services to be provided over lines 140 simultaneously with the transmissions of system 1 1 1.

As with system 11, system 111 is further capable of transmitting, receiving and displaying in a real-time mode, whiteboard type data, such as spreadsheets and data bases. Worth noting at this point are several slight modifications to the system 11 that can be made to provide additional functionality. First, the encoding and decoding circuit 115, network interface board 135, and the signal conversion device 139 can be incorporated into a set-top box rather than a personal computer so that the video display unit is a television set. Such a configuration can operated with various transmission media such as coax Ethernet. Internet, or 38 gigahertz (GHz) wireless. The encoding and decoding circuits 15 and 1 15 noted in FIGs. 1 and 2 are a variable rate CODEC capable of encoding and decoding data at rates from 56 Kbps to 2.048 Mbps. This allows the systems 1 1 and 1 1 1 to communicate with any system using 56 or 64 Kbps increments up to full Tl/El line speeds, i.e., 1.544 Mbps.

The video overlay boards 25 and 125 have several functions. They act as a SVGA board for full 24-bit color capability, and allows for multiple signals to be placed into "windows", and allows the user to customize the widow size. The Video Overlay Boards also have 4 Mbps buffer for storage.

The access controller 35 and the network interface boards 135 allow for system flexibility. The systems 1 1 and 1 11 are operating on any protocol such LAN WAN V.l 1, ISDN, Switched 56/T1/T3/E1, Dial-up switched 384 service, Frame Relay, ATM, Ethernet/extended LAN/routed LAN, Satellite, Token Ring, to name a few.

Illustrated in FIG. 3 is the system 1 1 1 in conjunction with a local central office configured as a video dial tone network (i.e., POP) 148 for providing high bandwidth services to the customer premise via the present invention. At the customer premise is a handset telephone 149 for providing POTS, a television set which can function as a video display device 128, the computer 113 which can merely comprise a central processing unit on a single circuit board, and a HDSL unit 142. The HDSL unit 142 is connected to the video dial tone network via two pair copper lines.

At the video dial tone network, the two pair copper lines terminate at a Telco box 150. The Telco box 150 multiplexes or demultiplexes the signals between a voice switch 152 and HDSL bay 154 and the HDSL unit. The voice switch provides switching functionality for POTS calls, as well know. The HDSL bay comprises a plurality of HDSL modems, each of which has a dedicated pair at a customer premise. The HDSL bay 154 is connected to a DS1 cross-connect 156 for cross-connecting the incoming copper lines to fiber lines. The DS1 cross-connect 156 is connected via the fiber lines to a digital /analog converter (DAC) 158 that converts the analog signal from the customer premise into a digital signal and visa versa. The DAC 158 is connected to the POP long distance carriers 160, a video server 162, and a master processor 164.

The POP long distance carriers 160 can be connected to any one of the available long distance carriers, such as MCI, ITT or AT&T. The video server 162 allows the customer to dial up one of a variety of video services, a few of which are illustrated. The video server is a multiprocessor-based system with that is controlled by software that uses a customer data base to allow the customer to select a service and be provided with that service in real time. Examples of possible service include a video game library 166, a laser disk library 168, and a video mailbox for storing video messages much like leaving a voice message in a voice mailbox. Further, a digital tape device 170 is provide as a network back-up.

The master processor 164 controls the operations of the video server, billing via billing system 174, call setup and customer service. The billing system 174 provides billing services using a routing table and 6 second billing intervals for you telephone bill. This essentially comprises monitoring to what location the call was placed and how long the call lasted, as is common in the industry.

The inventor has given a non-limiting description of several embodiments of the present invention, to which many changes may be made without deviating from the spirit of the inherent inventive concept. While this invention has been described with reference to such illustrative embodiments, this description s not intended to be construed in a limiting sense Various modifications and combinations of the various embodiments as well as other embodiments of this invention will be apparent to a person skilled in the art upon reference to this description. It is therefore contemplated that the appended claims cover any such modifications and/or embodiments that fall within the true scope of the presefit invention.

Claims

CLAIMSWherefore, the following is claimed:

1. A video conferencing system, comprising: audio input means for receiving audio signals and converting said audio signals into a digital audio signal; video input means for receiving video signals and converting said video signals into a digital video signal; encoding/decoding means for encoding/decoding said digital audio signal and said digital video signal into a single digital bit stream; network interface means for demultiplexing said single digital bit stream into a plurality of audio/visual signals on parallel circuits; conversion means for converting said audio/visual signals into a Tl/El signal; modem means for transmitting said Tl/El second signal over two-pair copper wires of the local exchange company using carrierless amplitude and phase modulation.

2. The system of claim 1, wherein said encoding/decoding means comprises a CODEC having a 640 X 480 pixels resolution.

3. The system of claim 1, wherein network interface means comprises a V.l 1 interface board that outputs an RS-449 signal.

4. The system of claim 1, wherein said conversion means comprises a channel service unit.

5. The system of claim 1, wherein said modem means utilizes high-bit- rate digital subscriber line (HDSL) protocol.

6. The system of claim 1, further including a video overlay board connected to said video input means for motion estimation of said video signal.

7. A method for video conferencing, comprising the steps of: receiving audio signals from an. audio input device and converting said audio signals into a digital audio signal; receiving video signals from a video input device and converting said video signals into a digital video signal; encoding/decoding said digital audio signal and said digital video signal into a single digital bit stream; demultiplexing said single digital bit stream into a plurality of audio/visual signals; converting said audio/visual signals into a Tl/El signal; transmitting said Tl/El signal over two-pair copper wires of the local exchange company using carrierless amplitude and phase modulation.

8. The method of claim 7, wherein said step of transmitting includes utilizing high-bit-rate digital subscriber line (HDSL) protocol.

9. The method of claim 7, wherein said step of multiplexing results in an RS-449 signal.

10. The method of claim 7, wherein said step of encoding/decoding is performed by a CODEC having a 640 X 480 pixels resolution.

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