Peripheral video conferencing system

IS 2 201 117 T3

DESCRIPTION

Peripheral videoconference system.

Field of the invention

The present invention relates generally to video conferencing systems, and more specifically, to a peripheral video conferencing system adapted for autonomous use and operation with a separate central computer system.

Background of the invention

Video teleconferencing systems are known which employ custom audio and video processing components and proprietary signal processing techniques to conduct video teleconferences over a dedicated network link. Previous custom video teleconferencing systems, such as the one illustrated in Fig. 1, typically employ a local video processing system 20 and a remote video processing system 30 that exchange audio and video information over a dedicated or specialized network link 26. Manufacturers of such prior art video processing systems typically use custom audio and video components in the design and manufacture of custom video encoder-decoder (CODEC) assemblies that generally communicate only with produced CODEC assemblies. by the same manufacturer. The use of custom CODEC sets typically requires the use of custom communication interfaces 24 and 30 to connect the custom video processing systems 20 and 30 to the dedicated network link 26.

The use of custom audio / video CODEC sets and signal processing techniques generally results in the manufacture of high-cost, low-volume systems that are typically only affordable to government agencies and large companies. Early custom video processing systems 20 and 30 sold for more than $ 100,000 per individual system, with operating costs often exceeding $ 200 per hour to communicate over a dedicated network link 26.

Recent advances in video teleconferencing technology have resulted in reduced production and purchasing costs for video teleconferencing systems. In 1993, two emerging leaders in the video teleconferencing systems market, PictureTel and Vtel, were selling systems that had an acquisition price of approximately $ 40,000. However, these and other prior art video teleconferencing systems continue to employ custom audio and video components and signal processing techniques. The high costs involved in acquiring and operating prior art video teleconferencing systems and, in particular, the lack of compatibility between heterogeneous systems, severely limits the effectiveness of video teleconferencing as a communication tool for businesses and individuals.

Desktop video conferencing systems have recently been developed to take advantage of the relatively low cost processing power of today's personal computer systems. Manufacturers of such desktop video conference systems generally produce and market a set of video conference computer cards which, together with the computer system in which the cards are installed, provide a desktop video conference of limited quality and functionality. A set of video teleconferencing cards adapted for use in a central computer system typically comprises three individual computer cards, each of which must be installed in a corresponding card slot within the computer system chassis. A conventional personal computer system 40 is illustrated in FIG. 2 with its frame removed. A typical personal computer system generally includes a power supply 42, one or more hard disk drives and floppy disk 44, internal random access memory, and up to eight card slots, all of which are generally connected to a motherboard 51 and communicated to through it.

Typically, the user of a prior art desktop video conference system must disassemble the computer system chassis to gain access to the internal components, install the three video conference cards in the three card slots 46, 48, and 50, modify the settings of various configuration switches on the motherboard 51, reassemble the cage cover and the computer system base, and then reconfiguring the operating system software of computer system 40 to recognize and communicate with the newly installed set of video teleconferencing cards. Although the cost of the prior art desktop video teleconferencing systems is comparatively less than that of the video processing systems 20 and 30 discussed above, the cost of such desktop systems continues to be prohibitive for many businesses and the consumer. particular. More significant is the fact that a potential purchaser of a prior art video conference system may not be able or unwilling to dedicate up to three internal card slots 46, 48 and 50 for the installation of the video conference cards. Furthermore, the typically complex task of reconfiguring both the hardware and software of the personal computer system after the installation of the video teleconferencing card assembly to facilitate desktop video teleconferencing can discourage a user from investing in such a cumbersome system. .

Conventional video teleconferencing systems illustrated in Figs. 1 and 2 fail to provide a high degree of ease of transportation from one conference site to another. The system shown in Fig. 1

ES 2 201 117 T3 is typically permanently installed in local and remote dedicated conference rooms, where parties must meet in order to participate in a video conference call. Access to the dedicated network link 26 is generally only available at permanent conference sites, thus preventing the ability to relocate the video teleconferencing systems 20 and 30 to other desired conference sites.

Transporting the prior art desktop video teleconferencing system illustrated in Fig. 2 to a new conference site is equally impractical. The desktop computer system 40, keyboard, monitor, cables, and any other connected peripheral devices must be disconnected, transported, and then reconnected at the new conference site. Although a prior art desktop video teleconferencing system 40 and associated hardware can be transported with great effort, such systems generally require a dedicated network link that is generally not available at other desirable conferencing sites. Furthermore, the use of custom audio / video components and signal processing techniques continues to severely limit the portability of prior art desktop video teleconferencing systems.

There is a desire among manufacturers and users of video teleconferencing systems to minimize the complexity of installing, configuring, and operating a video teleconferencing system. Furthermore, there is a desire to increase the portability of a video teleconferencing system to facilitate convenient transportation of the system to a plurality of conference sites.

In addition, there continues to be a compelling need in the community of video teleconferencing equipment manufacturers to provide full-motion, full-color video teleconferencing systems that can communicate in accordance with internationally recognized communication standards, and that can be purchased from relatively low cost. The present invention meets these and other needs.

Summary of the invention

The present invention is an audiovisual communication peripheral system that communicates with analog and digital communication channels to transmit video, audio, and other information, acquired from a local conference site, and receive audio and video information from a site. conference call. The invention further comprises a high speed interface for communicating with a separate central computer system and includes the visual conferencing computer application to enhance the functionality of the audiovisual communication system.

Brief description of the drawings

Fig. 1 is a block diagram of prior art video processing systems incorporating custom audio and video components and custom communication interfaces for transmitting and receiving information over a dedicated network link;

FIG. 2 is a generalized plan view of a prior art personal computer system with the chassis cover removed and three prior art video teleconference cards installed in the computer system.

Fig. 3 is an illustration of a video conferencing system employing a novel peripheral audiovisual communication system;

Fig. 4 is an illustration of various boards of a novel audiovisual communication system;

Fig. 5 is a block diagram of a novel audiovisual communication system connected to a communication channel;

Fig. 6 is an illustration of various connectors, plugs, and transceivers, which comprise the interfaces of the output, input and communications channels of a novel audiovisual communication system;

Fig. 7 is a schematic illustration of a video conferencing system employing the novel audiovisual communication systems that provide video conferencing between local and remote conference sites over a communication channel;

Fig. 8 is a block diagram of a video processing board suitable for processing local or remote video signals communicated to a novel audiovisual communication peripheral system;

Fig. 9 is a functional diagram of an audio processing board suitable for processing local and remote video signals communicated to a novel audiovisual communication peripheral system;

Fig. 10 is a generalized illustration of various information fields comprising a read or write coordination instruction produced by a central computer system and the visual conferencing computer application that accompanies and operates therein, and is transmitted through of a high-speed interface connecting the separate central computer system and a novel audiovisual communication system.

IS 2 201 117 T3

Fig. 11 is a schematic illustration of the configuration of a video conferencing system that employs two novel audiovisual communication peripheral systems, the related central computer systems being connected thereto, communicating cooperatively to provide window sharing and document collaboration between a local and a remote conference site;

Fig. 12 is a generalized flow chart illustrating various processing steps related to window sharing and document collaboration functions, coordinated by visual conferencing computer application operating on a central computer system in cooperation with a peripheral system. audiovisual communication;

Fig. 13 is a generalized flow chart illustrating various processing steps related to coordinating enhanced visual conferencing functions organized by visual conferencing computer application operating on a central computer system in cooperation with a peripheral communication system. audiovisual;

FIG. 14 is an illustration of one embodiment of a peripheral cage configuration for a novel audiovisual conferencing peripheral system; Y

FIG. 15 is an illustration of a rear panel of a peripheral cage configured with a plurality of input and output connectors, pins, and transceivers for a novel audiovisual conferencing peripheral system.

Detailed description of the preferred embodiments

Referring now to the figures, and more specifically to Fig. 3, a videoconferencing system is shown that includes a novel peripheral audiovisual communication system 70 adapted to communicate audio and video signals 80 and 78 through a communication channel. 82, and receiving remote audio and video signals transmitted over communication channel 82 from a remote conference site. In one embodiment, the audiovisual communication peripheral system 70 is configured to transmit to an external monitor 76 remote video image signals received from a remote conference site via communication channel 82, and remote audio signals to a internal speaker 90. In another embodiment, the audiovisual communication system 70 is configured to communicate with a separate central computer system 72 through the output interface 140 of a high-speed central computer system. Video images received from a remote conference site can be viewed through a display device 74 connected to central computer system 72, and the remote audio signal can be transmitted through internal speaker 90.

In comparing the novel audiovisual communication system 70 shown in Fig. 3, with the prior art video teleconferencing systems discussed above with respect to Figs. 1 and 2, it will become immediately apparent that the autonomous audiovisual communication peripheral system 70 makes possible a considerable reduction in the cost and complexity of conducting a video conference. More obviously, the audiovisual communication peripheral system 70 provides full-motion, full-color video conferencing between local and remote conference sites simply by connecting the audiovisual communication system 70 to a communication channel 82, for example a standard telephone line, a source of video signals 78 such as a video camera, and an external monitor 76 such as a television monitor for displaying remote video images. The built-in microphone 91 is adapted to receive local audio signals for communication with a remote conference site, and an internal speaker 90 is provided to transmit the remote received audio signal. It is noted that the audiovisual communication system 70, being a compact, self-contained peripheral, is well suited for easy transportation to any one of a plurality of desired conference sites.

An important advantage of the novel audiovisual communication system 70 is the effective disconnection or separation of the various audio and video processing sets necessary to conduct a video conference from a central computer system 72. As illustrated in Fig. 4, all the video and audio processing boards and components that make up the audiovisual communication system 70 are housed in a peripheral cage 115 completely separate from the central computer system 72. Consequently, the user of the audiovisual communication peripheral system 70 does not need to install any other cards in the central computer system 72, nor does he need to reconfigure the hardware or software of the operating system of the central computer system 72 to conduct a high-quality video conference. and with all the benefits. The user only needs to connect the novel audiovisual communication peripheral system 70 to a central computer system 72 using a standard connection interface.

As further shown in Fig. 4, a frame cover 114 is removably secured to a frame base 116, together with which it forms a peripheral frame 115, within which are housed the components of the audiovisual communication system 70. An input / output board 112 preferably includes means for communicating, between a motherboard 100 and various connectors, pins, and transducers mounted on a rear panel 123 of the chassis for peripherals 115, audio and video signals that communicate between a communication site. local conference and one remote conference. A video card 104 processes remote video signals received from communication channel 82, and transmits a source of processed video signals 78, acquired from a local conference site through communication channel 82. Audio card 102 processes remote audio signals

ES 2 201 117 T3 received from communication channel 82, and processes audio signal sources 80, for transmission through communication channel 82.

In Figs. 14 and 15 another possible configuration of the peripheral frame 115 is illustrated. The configuration of the frame case 117 is generally rectangular in configuration with open end portions adapted to respectively receive a front frame bezel 119 and a rear panel 123. front frame bezel 119 preferably holds a built-in speaker 90 and a built-in microphone 91. A plurality of video, audio, communication channel and power connectors and adapters are mounted on the rear panel 123. A light 121, preferably mounted in the cage box 117, alerts the user of the audiovisual communication system 70 when the visual conference session is being held. It is noted that light 121 can include an incandescent, fluorescent, light-emitting diode, or any other known light source.

Transmission and reception of local and remote audio and video signals over communication channel 82 is preferably facilitated by a communication board 106 that is provided within peripheral cage 115. Communication board 106, being connected to motherboard 100 and rear panel mounted communication channel transceivers 12, communicates with audio board 102 and video board 104 to respectively transmit and receive local and remote audio and video channels over communication channel 82. It is noted that communication channel 82 is generally connected to a domestic or international communication network 84. It is further observed that the communications channel 82 has a conventional analog telephone service configuration (Basic Telephone Network or RTB), or a digital communications channel, such as an ISDN digital communications channel (Integrated Services Digital Network). Communications board 106 preferably includes a high speed modem for transmitting audio, video, or other information signals over an analog communications channel. The power for the AV system 70 is provided by a power supply 108 connected to the motherboard 100. The power supply 108 is preferably a universal switching AC power supply capable of supplying a wide range of supply voltages preferably between 85 and 264 volts and at frequencies ranging from 47 to 63 Hertz for operation in both domestic and international power supply systems.

An important feature of the novel audiovisual communication system 70 concerns the high speed output interface board 110 adapted to communicate with a separate central computer system 72. In one embodiment, the local and remote video signals are communicated to the separate central computer system 72 via a SCSI (Small Computer Systems Interface) bus or interface. In another embodiment, the output interface board 110 comprises a PCMCIA (Personal Computer Memory Card Industry Association) bus or interface to provide high-speed communications between the audiovisual communication system 70 and various types of devices. central computer systems 72, including portable computer systems.

Referring now to FIG. 6, an input / output panel 120 is shown comprising an output interface panel 122, an input interface panel 150, and a communication channel interface panel 170. The input / output panel 120 is preferably configured and mounted as a rear panel 123 at the rear of the frame for peripherals 115, and provides means for connecting the internal video, audio and data processing assemblies of the audiovisual communication system. 70 to the audio and video signal sources 80 and 78, to the communications channel 82, to the central computer system 72, to the external speaker 220 and to the monitor 76. The input interface panel 150 preferably includes a main video input jack 154 for receiving NTSC (National Television Standards Committee) or PAL (Line Altered Line) 78 video signal sources. Generally a camcorder is connected to the video input jack 152, whereas a VCR is normally connected to the auxiliary video input jack, although a second camcorder can be used in place of a VCR. Video input panel 151 further includes main and auxiliary S-video input jacks 156 and 158 for receiving video signals from an S-video source 78.

Audio input panel 160 preferably includes a main audio input jack 162 and an auxiliary audio input jack 164, with both audio inputs 162 and 164 preferably being 2.0 volt line level compatible inputs. The main audio input jack 162 is generally connected to the audio output of a camcorder, where the audio output signal produced by the built-in microphone of the camcorder is received by the audio input jack 162. The jack Auxiliary Audio In 164 is normally connected to a VCR, but another option may be to connect it to the audio output of a second camcorder. An external microphone jack 168 is provided for receiving audio input signals from an external microphone, and, when used, preferably inhibits the built-in microphone 91 in the peripheral cage 115.

The output interface panel 122 preferably includes a video output panel 125, an audio output panel 127, and an interface panel 140 of a central computer system. Remote video signals received through communication channel 82 can be displayed on an external monitor 76 by connecting external monitor 76 to the video output jack 124. The video output signal that is provided at the video output jack 124 preferably conforms to one of the NTSC or PAL composite video signal standards. An S-video output jack is provided to allow connectivity to an S-video device.

The audio out panel 127 preferably includes a local audio out jack 128 and a remote audio out jack 130. The local audio out jack 128 is adapted to communicate audio signals

ES 2 201 117 T3 produced at the local conference site, while the remote audio output plug 130 is adapted to communicate audio signals produced at a remote conference site. The local and remote audio output jacks 128 and 130 are normally connected to the left and right audio audio inputs of a stereo VCR. An external speaker jack 132 provides a means to transmit remote audio signals through an external speaker 220. It is noted that remote audio signals are preferably routed to an internal speaker 90 unless an external speaker 220 is connected to the external speaker jack 132, where the internal speaker 90 is preferably inhibited.

In one embodiment, as discussed above, the audiovisual communication system 70 provides standalone video conferencing capability simply by connecting the audio and video signal source devices 80 and 78 to the audio and video input jacks 162 and 152 on the input interface panel 150, connecting an external monitor 76 to the video output jack, and connecting a standard or digital telephone line to the communication channel interface panel 170. In this configuration, the audiovisual communication system 70 provides full-motion, full-color video conferencing over a communication channel 82, displayed on the monitor 76 the remote video images and the remote audio signals being transmitted through the internal speaker 90.

The functionality of the video conferencing system illustrated in Fig. 3 is generally increased by connecting the peripheral audiovisual communication system 70 to a separate central computer system 72, and operating the computer video conferencing application preferably configured to operate in and in collaboration with the computer. central computer system 72. The central computer system 72, and the accompanying visual conferencing computer application, cooperates with the audiovisual communication system 70 to coordinate the presentation of local and remote video images on a display device 74 connected to the central computer system 72, and to generally increase the functionality of the audiovisual communication system 70. The visual conferencing software package can preferably be operated on both Windows-based^® as on Macintosh^®.

The output interface panel 122 includes a central computer system interface or interface panel 140 preferably comprising an interface connector and SCSI output 142 and / or a PCMCIA interface and output connector 148. A second SCSI or PCMCIA output and interface connector 144 is preferably available to daisy chain AV system 70 to other SCSI or PCMCIA peripheral devices. An identification (ID) switch 146 is provided to uniquely identify the audiovisual communication system 70 among other peripheral devices communicating over a common SCSI bus 113. When the central computer system 72 is connected to the central computer interface panel 140, it communicates with the audiovisual communication system 70 by preferably giving one or more coordination instructions to configure and coordinate the operation of the audiovisual communication system 70.

The connectivity between the audiovisual communication system 70 and the communication channel 82 is preferably provided by a communication channel interface panel 170. Communication via an ISDN digital communication line or a standard RTB communication line, the selectively provide an ISDN transceiver 172 and an RTB transceiver 174. Video conferencing over a standard RTB analog line is facilitated by an internal modem that can be operated at a transmission speed of up to 28,800 kilobits per second (kbit). The ISDN transducer 172 is preferably connected to an ISDN Basic Access (BRI) digital communication channel 82 that provides two 64 kbit data channels, one 16 kbit voice channel, and one 64 kbit signaling channel. The communications channel interface panel 170 may further include an optional channel transceiver 176 for communicating over a Primary Access ISDN (PRI) communications channel, a T1 line, a Switch-56 line, and various communication networks. local area and wide area.

Referring now to Fig. 5, there is shown a generalized functional diagram of a video conferencing system comprising an audiovisual communication peripheral system 70 and a separate central computer system 72. An input interface panel 150, comprising pins and appropriate input connectors, receives the 80 and 78 audio and video signal sources. The input interface panel 150 is preferably configured to receive sources of video signals 78 provided by at least two video sources, including, for example, a camcorder and a VCR, or alternatively, two camcorders. The source of audio signals 80, received from a built-in microphone 91 or an external microphone, is preferably transmitted to the local video processor 186 of the audio card 104.

The local audio processor 182 receives the audio signal source 80 preferably from the audio input panel 160, and transmits the audio signal source 80 to a central controller 200. A communication channel interface panel 170 receives the source of audio signals 80 transmitted from the central controller 200, and, in turn, transmits the source of audio signals 80 to the communication channel 82. In one embodiment, local audio processor 182 converts audio signal source 80 to the corresponding compressed audio signal in a predetermined compression format for efficient transmission over communication channel 82.

The video signal source 78, received by the video input panel 151, is transmitted to a local video processor 186 which is provided on the video card 104. The local video processor 186 processes the video signal source. 78 for transmission to the central controller 200, which, in turn, transmits the video signal source 78 to the communications channel interface panel 170 for transmission through the communications channel.

IS 2 201 117 T3

82. In one embodiment, the local video processor converts the source of video signals 78 received from the video input panel 151 into its corresponding compressed video signal in a predetermined digital compression format for efficient transmission over the channel. communications 82. It is noted that the video signal source 78 and the related audio signal 80 are generally transmitted together as a combined audio / video signal over the communications channel 82. The central controller 200 preferably synchronizes the signals from audio / video 80 and 78 when producing a combined audio / video signal.

Still referring to FIG. 5, a remote audio signal transmitted over communication channel 82 is preferably received by communication channel interface panel 170 and communicated to central controller 200. Central controller 200 transmits the signal. remote audio signal to remote audio processor 184 that is provided on audio board 102. Remote audio processor 184 includes means for converting a remote audio signal to its corresponding decoded remote audio signal. The decoded remote audio signal is preferably transmitted to an internal speaker 90 that is provided in the peripheral cage 115. The decoded remote audio signal is also transmitted to the output interface panel 122 and specifically to the jack for the external speaker 127. Connecting an external speaker 220 to the external speaker jack 127 to transmit the decoded remote audio signal preferably inhibits the internal speaker 90.

The communication channel interface panel 170 further receives remote video signals from the communication channel 82, and transmits the remote video signals to the central controller 200 for processing by a remote video processor 188 that is provided on the board. video 104. Remote video processor 188 typically receives from central controller 200 a compressed remote video signal that is preferably converted by remote video processor 188 into its corresponding decoded remote video signal. The video card 104 preferably transmits the decoded remote video signal to both the host computer interface panel and the video output panel 125. An external monitor 76 may be connected to the video output panel 125 to display a video image related to the decoded remote video signal thereon. The decoded remote video signal received by host computer interface panel 140 is preferably transmitted to SCSI interface 142 or PCMCIA interface 148 for communication to a separate host computer system 72 connected to host computer system 70. The central computer system 72 preferably coordinates the display of a video image related to the decoded remote video signal on a display device 74 connected to the central computer system 72.

In one embodiment, the video card 104 transmits the source of video signals 78 along with the remote decoded video signal to the host computer interface panel 140. A combined video signal that corresponds to the combination of the source of video signals and the decoded remote video signal, is preferably transmitted to central computer system 72 for simultaneous presentation on display device 74. Video images related to source and remote decoded video signals can be displayed respectively as side-by-side images, picture-in-picture, or any other desired combination of video images. remote and source on display device 74. The formatting and presentation of the remote and source video images are controlled by the central computer system 72, and more typically, through the cooperation of the central computer system 72 and the visual conferencing computer application operating therein.

The audio and video processors 182, 184, 186 and 188 of the audio and video cards 102 and 104 preferably comprise compression and decompression chips, also called CODEC chips, which encode and decode audio and video signals according to a standard internationally recognized videoconferencing facility. A suitable video conferencing standard is the CCITT H.320 standard promulgated by the International Telegraphy and Telephony Consultative Committee, a body of the International Telegraph Union (ITU) established by the United Nations. The CCITT H.320 video conferencing standard includes several sub-standards, including an H.261 video compression standard, an H.221 channel coding standard, and the G.711, G. 722 and G.728.

In accordance with another embodiment, the audiovisual communication system 70 includes a data channel or a high speed data transfer capability for transferring data files through the communication channel 82. A data file residing in the Central computer system 72, for example, is preferably transmitted to a data file processor 202 through the central computer interface panel 140. The central controller 200 then receives the transmitted data file from the data file processor 202, and, in turn, transmits the data file to the communication channel interface panel 170. The channel interface panel Communications station 170 transmits the data file through an ISDN transceiver 172 when audiovisual communication system 70 communicates through an ISDN digital communications channel 82. A high speed modem (not shown), preferably provided on communication board 106, receives the data file from central controller 200 before transmitting the data file through interface panel RTB 174 transceiver communication channel 170. The data file processor 202 preferably comprises data compression means for converting a standard data file to a compressed data file in a predetermined compression format for high speed transmission over communication channel 82.

A remote data file may be received by the communication channel interface panel 170, transmitted to the central controller 200, and then communicated to the data file processor 202. The data processor

ES 2 201 117 T3 data files 202 preferably converts a compressed remote data file to a standard remote data file, and is transmitted to the central computer system 72 through the central computer interface panel 140. Thus, the data file processor 202 of the audiovisual communication system 70 facilitates a high speed data file transfer link between a local central computer system 72 and a remote central computer system (not shown).

Data file processor 202 preferably provides high speed bi-directional data communication between two central computer systems communicating via communication channel 82. The data file processor 202, working in conjunction with two central computer systems communicating over the communication channel 82, provides various conference enhancement features including: data transfer, screen sharing, document collaboration, and more. data exchange features. Coordination of the data transfer procedure is simple and reliable. Central computing system 72, for example, preferably transfers blocks of data over communication channel 82 each time TRUE is assigned to a local SEND state, thus indicating that the remote central computing system is available to receive the data blocks. The local SEND state is set to TRUE initially, and then set to FALSE (false) after transmitting a first set of data blocks. The remote central computer system, after receiving the first set of data blocks from the communication channel 82, preferably transmits an OK SEND status signal to the local central computer system 72, but only after receiving the first set of local data blocks. without errors. The local central computer system 72 may then transmit other data blocks to the remote central computer system.

The RECEIVE status signal indicates that the incoming data blocks have been received from a remote conference site and are waiting to be processed at the local conference site. The local host computer 72 will transmit an OK SEND status signal to the remote conference site after processing the incoming data blocks. If a data block is not properly communicated between a local central computing system 72 and a remote central computing system, the data block will be automatically retransmitted. Consequently, the overload state or data loss is prevented. The data file processor 202 preferably handles all handshake and error detection / correction procedures. The data file processor 202 preferably further comprises dual buffer means to ensure optimal utilization of the transmission bandwidth of the communication channel 82. The dual buffer allows the local central computer system 72, for example, to transmit a second set of data blocks to the data file processor 202 while a first set of data blocks is being transmitted over the communication channel 82.

An important feature provided by the data channel or high speed data transfer capability of the audiovisual communication system 72 is the ability to view and modify a document that is simultaneously being viewed at a local and remote conference site. Referring now to Figs. eleven and 12, the novel audiovisual conferencing edge system works in conjunction with a central computer system and visual conferencing computer application to provide document collaboration and window sharing functions, which can be initiated at a local or remote conferencing site. It is assumed that the local and remote central computer system operating systems 244 and 246 are capable of operating at least one computer application within one of a plurality of activatable windows of the computer application.

The user of the local central computer system 244, for example, preferably initiates window sharing and document collaboration by first opening one or more windows of the local application in step 624, using the application names or designations as input selections. of previously opened windows just before the user displays the local window menu 600 in the foreground of the local display device 248. The applications related to each of the windows are preferably presented in alphabetical order to be selected in menu 600.

The user, in step 628, then selects a local active application window 602 from the menu to share with a remote conference site. The local central computer system 244, in step 630, preferably allocates an appropriate amount of system memory to accommodate an off-screen window local buffer 606. A copy of the pixels or pixel data defining the local active window 602 is transferred to the local off-screen window buffer in step 632. The local active window selected from the window menu 600 is then brought to the first drawing of the local display device 248 in step 634. All the pixels that make up the video image within the local active window 602 that is displayed in the foreground of the local display device 248 are then copied to the off-screen local buffer 604 at step 636.

The visual conferencing software application detects whether a local draw command has been given in step 638, typically detecting activity from a mouse or keyboard that forms the local user interface 246, for example. In response to the local draw command, the pixels in the local active window 602 affected by the local draw command are modified or updated in step 642. Modified pixel data from within local active window 602 is recorded or updated in local pixel update table 606 at step 640, typically in the form of pixel characteristics and position data. The updated pixel data is then copied to the local off-screen window buffer 601 in step 636, thus resulting in a replica of the local active window 602 that is held in the local off-screen window buffer. 604. In practice, the data

ES 2 201 117 T3 of original pixels residing in certain memory locations in the off-screen window buffer 604 are generally overwritten or replaced by the modified pixel data corresponding to the same memory locations.

At an appropriate time, the pixel data residing in the local off-screen window buffer 604 is transferred to the local audiovisual communication system 242 for transmission over the communication channel 82 in step 644. It is noted that the transmission of local pixel data via data or communication channel 82 in step 644 may continue subsequently or simultaneously with processing steps 638, 642, 640 and 636 related to modifications made to the pixels of the local active window.

A remote central computer system 264 preferably operates the visual conferencing computer application in a manner substantially similar to that which operates in the local central computer system 244 to enhance video conferencing between the remote and local conference sites. After establishing a communication link between the remote and local central computer systems 244 and 246, initially a full update of the pixel data related to the video image of the entire local active window 602 is transmitted as reflected in the buffer. local off-screen window 604, via communication channel 82 and is received by remote audiovisual communication system 262 at step 650. Pixel data related to the entire local active window 602 is first copied into the remote off-screen window buffer 610 in step 652, and subsequently transferred, in step 654, to the remote active window 608 which is displayed. in the foreground of the remote display device 268.

The modified pixel data transmitted in step 644 through data channel 82 is received at the remote conference site in step 650, then copied to the remote off-screen window buffer 610 in step 652, and they are subsequently transferred to remote active window 608 in step 654 to update the video image displayed therein. It is noted that a conferencing party at the remote conferencing site can also make changes to the document or application that is currently being shared within the local and remote active windows 602 and 608. Remote central computer system 264 preferably cooperates with visual conferencing computer application to coordinate window sharing, modification, and updating in a manner similar to that discussed above with respect to local central computer system 244.

During window sharing and document collaboration procedures, a full update or transfer of all pixel data related to one of the active, remote or local windows 602 and 608 is generally performed when a conferencing party resizes of an active window, or after a predetermined amount of time has elapsed, programmed into an automatic timer, in order to periodically refresh the local and remote active windows 602 and 608. It is observed that the incremental update of the pixel information is carried out mainly to optimize the use of the available transmission bandwidth of a communications channel 82 with limited bandwidth. Other optimization procedures, such as converting pixel data into a compressed format using one of several standard compression procedures, can be employed to increase the efficiency of pixel data transfer between a local and remote conference site. when performing window sharing and document collaboration functions.

An important advantage of the novel audiovisual communication system 72 has to do with its ability to work with various central computer systems 70 and related operating systems. The ability to communicate with virtually all popular central computer system platforms greatly increases the portability of the AV Communication System 70, and makes full-featured video conferencing available to most commercial, government, and personal uses. Cross-platform and multi-platform video conferencing (operation between two computers running different operating systems) is preferably facilitated by the visual conferencing computer application, which can be operated on the central and / or remote computer systems.

In general, the manner in which a given central computer system 72 processes video data varies from one computer system manufacturer to another. Since no single video processing standard has been adopted for exclusive use among manufacturers of central computer systems, the novel audiovisual communication system 70 preferably performs almost all important video processing tasks before transferring the data. video through an output interface 140 to a central computer system 72 connected for presentation on a display device 74. Virtually all popular host computer systems are generally configured to communicate over one of a limited number of standard output interfaces, such as a SCSI 142 or PCMCIA 148 interface, for example. The AV communication system 70 provides compatibility with virtually all popular core computer systems 72 regardless of processor, by formatting the video data into a form that can be transmitted through the standard output interface 140 and processed by a Specific central computer system 72 connected to audiovisual communication system 70.

A central computer system 72, in conjunction with the visual conferencing computer application operating therein, preferably gives various coordination instructions to audiovisual communication system 70 to facilitate video conferencing between a remote and a local conference site. The central computer system 72 coordinates

ES 2 201 117 T3 preferably transferring the video image data between the audiovisual communication system 70 and the central computer system 72.

The central computer system 72 preferably gives read and write request instructions to the audiovisual communication system 70 to coordinate the transfer of video data therefrom in a similar manner to when communicating with other peripheral devices, such as a drive unit assembly. disk, for example. In response to the read and write request instructions, the audiovisual communication system 70 transfers the requested number of video images and other configuration parameters between the central computer system 72 and the audiovisual communication system 70. According to this embodiment, the audiovisual communication system 70 functions as a slave to the central computer system 72, whereby all coordination instructions are produced by the central computer system 72, and answered by the audiovisual communication system 70.

In one embodiment, the output interface 140 comprises a SCSI interface 142, in which the communication between the central computer system 72 and audiovisual communication system 70 conforms to one of several standard SCSI communication protocols, such as the SCSI-I and SCSI-II protocols. The central computer system 72 preferably gives coordination commands or instructions in the form of parameter blocks. Each parameter block typically includes a field for an operation code (opcode) that specifies the particular operation to be executed, and also includes data and related configuration parameters that are used to perform the operation. The opcode field is generally included at the beginning of the parameter block followed by the data and configuration parameters unique to that particular opcode. The configuration parameters typically specify the type of video data and the manner in which the video data transferred from the audiovisual communication system 72 is presented on the display device 74.

For example, as illustrated in FIG. 10, a generalized diagram of typical information contained in a read or write coordination instruction 500 suitable for coordinating communications between the central computer system 72 and the audiovisual communication system is shown. 70 through SCSI output interface 142. It should be understood that peripheral communication protocols other than those conforming to the SCSI standard may be employed to effect communications between the central computer system 72 and the audiovisual communication system 70 without departing from the scope of the present invention. By way of example, a PCMCIA interface 148 and the communication protocol related thereto may be employed.

By way of illustration and not limitation, the coordination instruction 500 shown in FIG. 10 comprises an ID field 508, a logical unit number field 506, and a data block field 502 that includes a data field field. first data byte 504. Both the read and write request instructions are preferably structured to include the information fields illustrated in FIG. 10. The ID field 508 provides an identification to distinguish the AV communication system 70 from other peripheral devices that communicate over the SCSI bus 113. The logical unit number field 506 preferably indicates the type of data being transferred when the central computer system 72 is reading or transferring the information from audiovisual communication system 70. The logical unit number field 506 is preferably involved only during a read transfer operation, and is typically set to zero during write transfer operations.

The first byte data field 504 of the data block field 502 preferably indicates the type of data transferred during a transfer write operation. Specific information or data that is transferred during a read or write transfer operation is contained within data block field 502. The number of bytes that make up the data block field 502 preferably depends on the specific type of read or write request instruction generated by the central computer system 72. For example, if the central computer system 72 gives a read request instruction to transfer video information from the audiovisual communication system 70 to the central computer system 72, a fixed predetermined number of bytes of video data is transferred in the field of data block 502. When the central computer system 72 gives a read status request instruction, for example, in the data block field 502 a fixed predetermined number of bytes of data related to the status information is transferred. Continuing with the example, when the central computer system 72 writes a data block to the audiovisual communication system 70, the size of the data block 502 that is being transferred is obtained from reading the first data byte field 504 of the data block. data 502. Accordingly, each specific type of coordination instruction 500 is assigned a predefined size for the data block field 502.

Continuing with reference to Fig. 10, the video data contained in data block field 502 is shown organized in an RGB (Red, Green, and Blue) format for a pixel matrix, in which Each pixel corresponds to a single point on a monitor or color television screen. Each pixel 512, in turn, consists of red, green, and blue color components. The format of the pixel data of the data block 502 preferably depends on the particular CPU (Central Processing Unit) of the central computer system 72. The red, green and blue color components are preferably quantized into three 5-bit fields 516, 518 and 520 for Macintosh-based computer systems^®/ Motorola^®. In practice, each individual pixel 512 is preferably associated with 16 bits, or two 8-bit bytes, of color component data. Thus, the extra most significant bit 514 is set to zero. For core computing systems 72 employing a Windows-based architecture^®/ Intel^®, the color components of each pixel 532 are preferably quantized in the following sequence

ES 2 201 117 T3 of 530 fields: a 3-bit green field 536, a 5-bit blue field 538, a 1-bit unused field 540, a 5-bit red field 542 and a green field of 2 bits 544. It can be seen that the quantization of the three color components for each pixel configuration 512 and 532 according to these preferred formats provides up to 32,678 (2¹⁵ ) color combinations. It should be understood that other central processors or CPUs may be employed in the central computing system 72 other than those discussed above, and that the audiovisual communication system 70 may accommodate such other processors by formatting the pixel data related to local video signals. and remote in a form capable of being transmitted through the output interface 140 and processed by the particular central computer system 72.

It is noted that the video data block field 502 generally consists of a repeating sequence of red, green, and blue data fields (not necessarily in this order), and the maximum amount of pixel data comprises a single block field. data 502 that is limited by the size of the predefined data block 502 imposed by the specific read or write video transfer coordination instruction that the central computer system 72 is executing. The following computer code in C language represents, for example, a typical coordination instruction related to a block of parameters of the superimposed image display command:

OSErr VBoxHostPIP (long width, long height, long croppedX, long cropped Y, long top, long left, RGBColor borderColor, short borderWidth)

OSErr err;

S HOST_PIP; // parameter block op.opcode-OP_HOST_PIP; // parameters specific to op.sizex = width // opcode (opcode) op.sizey = height op.cropx = croppedX; op.cropy = croppedY; op.posx = top; op.posy = left; op.color = 0;

op.color = borderColor.red >> ll; op.color << = 5;

op.color + = borderColor.green>> 11; op.color << = 5;

op.color + = borderColor.blue>> 11; op.width = borderWidth;

gHeader [0] = kSCSIWrite; // SCSI command block header gHeader [1] = 0 gHeader [2] = sizeof (S_HOST_PIP) >> 16; gHeader [3] = sizeof (S_HOST_PIP) >> 8; gHeader [4] = sizeof (S_HOST_PIP);

ES 2 201 117 T3 gHeader [5] = 0;

gBlock [0] .scOpcode = scNoInc; // SCSI command gBlock [0] .scParaml = (long) & op;

gBlock [0] .scParam2 = sizeof (S_HOST_PIP);

gBlock [1] .scOpcode = scStop;

gBlock [1] .scParaml = 0;

gBlock [1] .scParam2 = 0;

er = VboxWaitBusu ();

if (err == no Err) return (SendWriteCommandToSCSl (& gHeader, gBlock)); else return err;

The computer code for other coordination instructions structured in the form of parameter blocks is preferably similar to that presented above by way of illustration for an overlay display instruction.

Coordination instructions related to the transfer of data file information over communication channel 82, to facilitate window sharing and document collaboration, are preferably structured in a parameter block command format similar to that illustrated. in Fig. 10. The first two parameters of a data transfer coordination instruction are typically an opcode and a block length code. These two parameters preferably define the structure and content of the entire data transfer parameter block command. The opcode for a display or drawing coordination instruction, for example, will typically include a display opcode, a block length code that defines the total number of bytes that make up the parameter block command, and a plurality of pixel data indicating the position on the screen and the characteristics of each pixel.

To facilitate data transfer between different host computer platforms, the pixel data can include added data in the form of embedded commands that instruct a particular CPU to process the pixel data in a particular way. When two similar CPUs communicate data over communication channel 82, the embedded command can be ignored or preferably not included in the pixel data. When cross-platform data transfer is desired, the receiving CPU preferably extracts the embedded commands and processes the pixel data related thereto according to the instructions. An embedded command, for example, may instruct the receiving CPU to swap the position of specific color bits of the pixel data block as discussed above with respect to Fig. 10.

In another embodiment, as illustrated in Fig. 7, a local audiovisual communication system 242 and a remote audiovisual communication system 262 are shown communicating through a communication channel 82. The local audiovisual communication system and the remote 242 and 262 preferably operate in accordance with an industry recognized international communications standard, such as the CCITT H.320 standard. The local audiovisual communication system 242 receives and processes local source audio and video signals 252 and 254 from a local conference site 240. The signals from local source audio and video sources 252 and 254 are then transmitted to a broadcast channel. communications 82. Local source audio and video signals 252 and 254 transmitted through a communication channel 82 are received and processed by remote audiovisual communication system 262 located at a remote conference site 260.

Remote source audio and video signals 272 and 274 are received and processed by remote audiovisual communication system 262, transmitted through communication channel 82, and received and processed by local audiovisual communication system 242. Connectable a local monitor 281 to the local audiovisual communication system 242 to display remote video images received from the remote conference site 260. Similarly, a remote monitor 283 can be connected to the remote audiovisual communication system 262 to display local video images at the remote conference site 260. According to this embodiment, the local and remote audiovisual communication systems 242 and 262 connected respectively to the local and remote monitors 281 and 283, and to the communication channel 82, provide full-motion, full-color, autonomous videoconferencing.

IS 2 201 117 T3

According to another embodiment, each of the local and remote audiovisual communication systems 242 and 262 is connected respectively to local and central computer systems 244 and 264 via local and remote output interfaces 250 and 270. The local and central computer systems 244 and 264 respectively coordinate the transfer of video information between the local and remote audiovisual communication systems 242 and 262 for display on the local and remote displays 248 and 268. In addition, the local and central computer systems 244 and 264 preferably configure, adjust and modify various operating parameters of the local and remote audiovisual communication systems 242 and 262, such as the color, contrast and brightness characteristics of the processed video signals, the volume settings of the internal or external speakers 90 and 220, and the connection to a communications channel 82 ISDN or RTB, for example.

In accordance with the system configuration illustrated in FIG. 7, a visual conferencing computer application package may preferably be operated on each of the local and central computer systems 244 and 264. The visual conferencing software package preferably enhances and enhances the functionality of the local and remote audiovisual communication systems 242 and 262 in the manner discussed above and to be discussed further below. The local central computer 244, for example, preferably gives one or more coordination instructions to the local audiovisual communication system 242 for organizing the transfer of video data received from the communication channel 82 by the local audiovisual communication system 242 for its transfer. presentation on local display device 248. In addition, the local host computer 244, in conjunction with the visual conferencing computer application operating on the local host computer 244, preferably gives one or more coordination instructions for effecting the transfer of data files between the local audiovisual communication system 242 and the remote audiovisual communication system 262 and the remote central computer system 264. It should be understood that the characteristics and functions set forth in reference to the local audiovisual communication system 242 are equally applicable to the remote audiovisual communication system 262.

Another important feature provided by the cooperation of the local host computer 244 and the visual conferencing software application package operating therein includes the ability to adjust or modify the effective transmission bandwidth of the communication channel 82 to increase or decrease the communications. transmission rates of audio, video and information data transmitted through the communications channel 82. In one embodiment, the communications channel 82 frequency bandwidth allocated between video, audio, and information data files sources may be modified by the central computer system 72 running a visual conferencing computer application. The transmission bandwidth of the communication channel 82 is preferably adjustable in finite increments in accordance with the specification of the CCITT H.320 standard.Any of the video, audio, and data file sources can be reduced or eliminated in order to increase the relative performance of the other sources. The adjustment of the transmission bandwidth of the communications channel 82 allocated for the transmission of audio, video and data file signals is preferably carried out within the limits imposed by the CCITT H.320 communication standard, or another internationally recognized standard. , to ensure the maintenance of the videoconference in full motion.

Another important feature, obtained through the cooperation of the local audiovisual communication system 242 and the local central computer system 242 and the visual conferencing computer application, is the ability to simultaneously display on any of the local and remote display devices. 248 and 268 the video images transmitted from the local and remote conference sites 240 and 260. The local audiovisual communication system 242, as will be discussed in detail with reference to FIG. 8, receives and maintains in the buffer both the local source of video signals 254 and the remote source of video signals 274, and produces a video signal representative of local and remote video signals. The local host computer 244 then transmits the local and remote video signals for display on the local display device.

In fig. 13 provides a generalized flow chart illustrating some of the more important coordination functions performed by the visual conferencing software application. The visual conferencing computer application is preferably operated on both the local and remote central computer system 244 and 264 to advantageously improve the operation of the local and remote audiovisual communication systems 242 and 262. A conferencing party begins the videoconference typically by running the visual conferencing computer application at step 702. The user is preferably presented with various options by presenting a main menu at step 704, including options for configuring the system, starting the conference. visual, and to conclude the visual conference session.

A conferencing party, in step 706, has the option of modifying various parameters that affect the configuration and operation of the local audiovisual communication system 242 and the local central computer system 244. In step 708, the user can select and modify various parameters that affect communication between the local audiovisual communication system 242 and the communication channel 82. The user, for example, can specify whether the visual conference will be established over a standard analog (RTB) or digital (ISDN) communications channel 82. An automated telephone book database can be established and accessed to assist a user when establishing a communication link with a conferencing party. Other communication characteristics can be controlled in step 708, such as the call log, which results in the recording of data related to incoming, outgoing and all kinds of communications between the local audiovisual communication system 242 and the communications channel 82.

IS 2 201 117 T3

A conferencing party, in step 710, can select and modify various video features and settings that affect both the local monitor 281, connected to the local audiovisual communication system 242, and the local display device 248, connected to the local central computer system. 244. A user may, for example, selectively decide to display video images related to a local source of video signals 254 received from a main or auxiliary video source 152 or 154. The superimposed image display mode can be enabled or disabled as required. want. The color, brightness, contrast and hue characteristics of the local source of video signals 254 can be adjusted preferably through on-screen controls adjustable by a conferencing party via a local user interface 246. In addition, the user can configure the local audiovisual communication system 242 at step 710 to display video images acquired from the local conference site, the remote conference site, or both conference sites. In step 712, various configuration parameters affecting local and remote audio can be modified. A conferencing party can modify, for example, the gain of the audio input of a main camera or an auxiliary camera. You can also control the volume level of an internal or external speaker 90 and 220.

A user can modify the operational characteristics of the data channel 82 and the data transfer capability of the local audiovisual communication system 242 in step 714. Data transfer via the communication channel 82 can be given a high priority. relative to the transmission of video and audio data, giving rise to the continuous transfer of the data bytes that make up the data files through the communications channel 82. Alternatively, the data file transfer procedure can be given a lower priority, resulting in selective transmission of data bytes in the background to ensure optimal transmission of video and audio data over communication channel 82. A conferencing party can start the visual conference from the main menu in steps 704 and 716, and establish a communication link between the local conference site 240 and the remote conference site 260 in step 718, typically by placing a call to via communications channel 82 to remote conference site 260. During the visual conference, the user has the option to modify the system configuration in step 722 and, in step 728, can modify various operational and configuration parameters discussed above with respect to the system configuration option in step 706 . The user can also modify the way the data files are transmitted over data channel 82 in step 726, which includes, for example, options to modify the priority of the data file transmission relative to the transmission of video and audio signals, and to encrypt and / or compress the data file prior to transmission. Visual conferencing between two conference sites 240 and 260 can continue until a conferencing party decides to end the video conference session, typically exiting the visual conferencing software application in step 720 or from the main menu in step 704.

During a video conferencing session between a local and a remote conference site 240 and 260, a conferencing party may wish to begin window sharing or document collaboration at step 724. An option to share a window presented in color is preferably provided. or in black and white to ensure continuous and reliable window sharing and / or document collaboration over a limited bandwidth communication channel 82. Conferencing parties, for example, may initially share a window presented in color, and subsequently switch to a black and white presentation in step 730 if degradation in image quality is observed, typically caused by a reduction in speed. data transmission over a data channel 82. The user can select a particular window to share, or can choose to stop or start window sharing or document collaboration as desired in step 730. The features and functions discussed above in connection with the visual conferencing computer application operating in conjunction with a central computer system are provided solely for the purpose of illustrating and exemplifying the enhanced functionality of a local and remote audiovisual communication system 240 and 262 when used. connect to the local and remote central computer systems respectively 244 and 264.

Another important feature concerns a novel video conferencing computer routine or application that can be operated on one or both of the local and remote central computer systems 244 and 264 to monitor incoming communications received through communication channel 82. Inbound communication detection application software, operable on local host computer 244, for example, preferably monitors signal flow through local outbound interface 250. The detection computer routine preferably operates independently of any other computer application that is running on the local host computer 244, and is preferably inaccessible and unnoticeable by the user of the local host computer 244. Thus, the detection computer routine operates in the background. and continuously monitors incoming communications by polling local outbound interface 250 regularly, once per second, for example. Upon detecting an incoming communication, the detection routine preferably initiates or executes an alerting routine software or computer application that preferably alerts the user of the local audiovisual communication system 242 of the incoming communication received through the communication channel 82.

The alert computer routine preferably interrupts the current operation of the visual conferencing computer application or any other computer application currently running on the local host computer 244, and presents the user with a plurality of options, including the option of respond to or ignore incoming communication. The local host computer 244, in response to a user's decision to respond to the incoming communication, gives a response coordination instruction to the local audiovisual communication system 242, and executes a visual conferencing computer application routine to receive and respond to incoming communication.

IS 2 201 117 T3

The user of the local audiovisual communication system 242 interacts with the local central computer 244 through a local user interface 246 connected to the local central computer system 244. The local user interface 246 is preferably a graphical user interface which, together with a mouse and keyboard connected to the local central computer system 244, provides the user with the means to communicate coordination instructions between the local central computer system 244 and the system. of local audiovisual communication 242. It is observed that graphical user interfaces, such as those created for computer systems based on Windows^® and Macintosh^®, are typically used to control or operate a central computer system. Those skilled in the art can create new graphical user interface programs, or modify existing ones, to include the function of controlling the operation of the local central computer 244 and, together with the visual conferencing software application, the local audiovisual communication system. 242.

Figs. 8 and 9 illustrate in functional diagram form the various audio and video components that make up the audio and video boards 102 and 104 illustrated in Figs. 4 and 5. An important advantage of the video card 104 comprising the audiovisual communication system 72 concerns the automatic detection and processing of video signals produced by an NTSC or PAL video source. The functional diagram of the video processing 300 shown in Fig. 8 includes a central controller 200 that coordinates the transmission and reception of video signals communicated through the communication channel 82. The main video input jack 152 and / or the auxiliary video input jack preferably receives the local video signals produced. at the local conference site 240 by an NTSC or PAL camcorder.

The NTSC standard sets a video frame rate of thirty video frames per second, while the PAL standard specifies a video frame rate of 25 video frames per second, to keep the video in full motion. A single moving video image typically comprises an even field and an odd field. The NTSC / PAL decoder 302 preferably converts a local NTSC or PAL video signal into its corresponding video image or decoded local pixel data at the output of the NTSC / PAL decoder 302. The NTSC / PAL decoder 302 performs automatically detecting and determining the format of the video signal while processing the header information and other data constituting an NTSC and a PAL video signal.

Decoded local pixel data is typically in RGB (red, green, blue) or YUV (luminance Y and color difference U and V signals) format. The NTSC / PAL decoder 302 preferably decodes the local NTSC video signals to obtain the corresponding CIF240 resolution image data (352 x 244), and the local PAL video signals to obtain the corresponding CIF resolution image data (352 x 288). A CIF240 resolution image is recognized as a standard image format for home video display devices, while a CIF (and QCIF) resolution image is recognized as an international image format standard.

When an even field of a local NTSC or PAL video image is processed, the NTSC / PAL decoder 302 preferably transmits to the local video encoder 304 local image data of CIF or CIF240 resolution depending on whether the local video source device it is a NTSC or PAL camera. Local video encoder 304 preferably includes scaling circuitry that scales a CIF240 resolution image to an appropriate CIF resolution image. When processing an odd field of a local NTSC or PAL video image, the NTSC / PAL decoder 302 preferably transmits the previously decoded even field CIF pixel or image data to the local image buffer 306 while simultaneously decoding the next odd field of local video image. This decoding procedure is preferably repeated for subsequent NTSC or PAL local video images received by the NTSC / PAL decoder 302. The local video encoder 304 preferably comprises circuitry for converting the decoded local video image data, typically in YUV format. , into the corresponding compressed local video image data. A suitable local video encoder 304 is model A4310A manufactured by AT&T, and a suitable NTSC / PAL decoder is model SAA7194 manufactured by Philips.

The image buffer 306 preferably comprises enough DRAM (dynamic random access memory) memory to temporarily or buffer the 256,000 local pixel data, which is sufficient to buffer two local CIF images. Thus, the local image buffer 306 provides a double buffering of the local CIF video image data, which, together with the online buffer 314 arranged between the local video encoder 304 and the video buffer local image 306. The reconstructed local CIF image data stored in the local image buffer 306 can then be routed to one or both of the output interfaces 140 and / or the video output pin 124 as decoded local video signals. Decoded local video image data processed by NTSC / PAL decoder 302 and video encoder 304 is also preferably transmitted to central controller 200 for communication over communication channel 82.

The remote video image signals transmitted through the communications channel 82 are preferably received by the central controller 200 and transferred to a remote video decoder 318. The remote video signals are converted by the video decoder 318 into corresponding decoded remote video image data. The reconstructed image data is stored in an online buffer 324 and temporarily stored in a remote online buffer 320. In a manner similar to that described above with respect to the NTSC / PAL decoder 302 and the local video encoder 304 , the odd and even fields of

ES 2 201 117 T3 remote video image data is successively decoded and reconstructed into decoded remote video image data, and buffered by cooperative processing between remote video decoder 318 and video buffer. remote image 320. The remote decoded video image data is then routed to one or both of the output interfaces 140 and / or the video output pin 124 as remote decoded video signals.

Another important advantage provided by the audiovisual communication system 70 concerns the simultaneous display of local and remote decoded video images on a video monitor 76 or a display device 74 connected to a separate host computer 72. In an embodiment that illustrated in Fig. 8, an output multiplexer 308 receives local and remote decoded video image data respectively from the local image buffer 306 and from the remote image buffer 320. The combined local and remote decoded video image data is stored in an online buffer 310 for output to the separate host computer 72 through the host computer output interface 140. Online buffer 310 is preferably provided to enhance transmission of local and remote decoded video image data between output multiplexer 308 and host computer output interface 140.

The combined local and remote decoded video image data is displayed as various combinations of the local and remote video images related thereto, on the display device 74 connected to the central computer system 72. The host computer system 72 preferably gives one or more coordination instructions to control the routing of the local and remote decoded video image data between the host computer output interface 140 and the video output pin 124. The output multiplexer 308 may preferably be commanded, for example, to transmit only the remote video image data to the host computer 140 output interface, rather than the local video image data or the host image data. local and remote video combined.

The combined local and remote decoded video image data may also be routed to the video output pin 124 through the display device multiplexer 330. The display device multiplexer 330 preferably controls the video image data transmitted to the NTSC / PAL encoder 332 and video output jack 124. Local, remote or combined video image data can be transmitted to the NTSC / PAL encoder 332 through the multiplexer of the display device 330. The video image data transmitted by the multiplexer of the display device 330 is converted to the format NTSC or PAL via the NTSC / PAL encoder 332 for communication to the video output jack 124 to finally be displayed on a NTSC or PAL monitor 76 connected thereto.

The NTSC / PAL encoder 332 is preferably configured to receive 704 pixels from the display device multiplexer 330 corresponding to a CIF video image respectively residing in each of the local and remote image buffers 306 and 320 (352 pixels local and 352 remote pixels provide 704 total pixels). If it is desired to display only the local and remote video images on the monitor 76 connected to the video output jack 124, the display device multiplexer 330 preferably performs 1 to 2 scaling (352 x 2) by stopping and holding local or remote pixels before being transferred to the NTSC / PAL 332 encoder. If the simultaneous presentation of the local and remote video image is desired, the display device multiplexer 330 transfers all 352 pixels of each of the local and remote image buffers 306 and 320 respectively to the NTSC / PAL encoder 332. A suitable display device multiplexer 330 is model XC3030 manufactured by Xilink, and a suitable NTSC / PAL encoder is model SAA179 manufactured by Philips.

Referring to Fig. 9, a functional diagram of the various components of the system 400 that processes the local audio signals acquired from a local conference site and the remote audio signals received through the communications channel 82 is shown. The signals Local audio is preferably input to an audio processor 406 from a plurality of audio sources. The main and auxiliary input jacks 164 and 162 are respectively provided in the peripheral cage 115 of the audiovisual communication system 70 to receive local audio signals typically from the audio outputs of a camcorder. The audio processor 406 can also receive local audio signals from an internal microphone 91, and an external microphone connected to the external microphone jack 168, or from a standard telephone microphone 440 connected to the converter 410 which converts the telephone audio signal. into an appropriate analog audio signal. In one configuration, an input multiplexer 408, with its output connected to audio processor 406, provides means for combining local audio signals produced by microphone 91 and telephone 440. Audio processor 406 preferably includes an analog-to-analog converter. digital to convert local analog audio signals to their corresponding local digital audio signals.

Local audio signals received by audio processor 406 are transmitted to and processed by audio encoder 404. The audio encoder preferably comprises audio coding circuitry for converting local digital audio signals into local compressed audio signals. The local digital or compressed audio signals are then transmitted to the central controller 200 which coordinates the transmission of local audio signals through communication channel 82. A suitable audio encoder 404 is the model DSP3210 manufactured by AT&T.

IS 2 201 117 T3

Remote audio signals transmitted through communications channel 82 are preferably received by central controller 200 and transmitted to an audio decoder 402. Remote audio signals are typically serially compressed audio signals according to one of several industry standard compression formats. The audio decoder 402 preferably converts the compressed remote audio signals into corresponding remote digital audio signals. In addition, the audio decoder 402 preferably comprises echo cancellation circuitry for filtering a local audio signal that is transmitted from a local conference site, and then transmitted back to the local conference site and received again by audio decoder 402.

The audio processor 406, which preferably includes an analog-to-digital converter, converts the remote digital audio signals into corresponding remote analog audio signals for transmission to a plurality of audio outputs, including a jack plug. local audio output 128, a remote audio output jack 130, an external speaker jack 132, and an amplifier 414 connected to an internal speaker 90. A suitable audio decoder is the DSP3210 model manufactured by AT&T. It is observed that the central controller 200 cooperates with the audio and video processing components 400 and 300 and the communication channel 82 to maintain the optimal operation of the audiovisual communication system 70.

Of course, it will be understood that various modifications and additions can be made to the preferred embodiments set forth above without departing from the scope of the present invention. Accordingly, the scope of the present invention should not be limited by the particular embodiments set forth above, but should be defined solely by the claims set forth below and their equivalents.