SLECTABLE AUDIO/VIDEO (A/V) DISTRIBUTION USING MULTI-MEDIA WORKSTATIONS, MULTI-CHANNEL A/V NETWORK, AND DIGITAL DATA NETWORK

Abstract: A number of multi-media workstations having network and audio/visual (A/V) software are provided to a master control and a number of user stations, and these multi-media workstations are coupled to a number of A/V sources and each other via a multi-channel A/V network and digital data network. Each of the multi-media workstations is equipped with a multi-channel analog A/V signal receiver, a digital data network interface, a high performance processor, A/V digitization and rendering circuitry, a high pixel density display, and speakers. The multi-media workstations are further equipped with an operating system having integrated network and A/V services, an A/V command handler module, an audio distribution module, an A/V command control module, and a number of A/V applications. The multi-media workstation provided to the master control station is further equipped with a master A/V control module. Together, these elements cooperate to allow A/V materials to be selectably distributed to the multi-media workstations.

Description: SELECTABLE AUDIO/VIDEO (A/V) DISTRIBUTION USING MULTI-MEDIA WORKSTATIONS. MULTI-CHANNEL A/V NETWORK. AND DIGITAL DATA NETWORK BACKGROUND OF THE INVENTION Field of the Invention: The present invention relates to the fields of computer systems, audio/video (A/V) devices, and networking. More specifically, the present invention relates to selectable A/V distribution to a number of local and/or remote stations. 2. Glossary of Terms: For the purpose of this disclosure, the intended meanings of certain key terms are as follows: a) a personal computer is intended to mean a microprocessor based computer equipped to handle traditional text and graphics data; b) a multi-media computer is intended to mean an enhanced personal computer equipped to handle digitized video and sound data as well as traditional text and graphics data, the digitized video and sound data being received from a digital A V player, such as a CD-ROM, playing an A/V title stored on a digital media, such as a CD, in digitized form; c) a multi-media workstation is intended to mean an enhanced multi-media computer equipped to digitize analog A/V signals into digital video and sound data, as well as being able to handle them. 3. Background: Today, many business or education applications desire selectable A/V distribution to local and/or remote stations in a cost effective manner. Since very often these local or remote stations also desire computing capability, it is more cost effective to have both desires satisfied with common equipment. In one educational system adapted for classroom usage known in the art, A/V materials are selectably distributed from one of a number of A/V sources to a number of teacher and student personal computers in a classroom under the control of the teacher's personal computer. The selectable A/V distribution is accomplished using three independent networks, a "peer to peer" digital data communication network, a star type analog video distribution network, and a star type analog audio and keystroke distribution network. In addition to standard personal computer equipment such as color graphics monitor, each personal computer is equipped with a "peer to peer" digital data communication network interface and a custom analog video input/output (I/O) interface. Additionally, each student personal computer is provided with a custom complementary analog audio and keystroke I/O unit. Furthermore, the system is provided with a custom analog video distribution unit, and a customer analog audio and keystroke distribution unit. Beside the disadvantages that the system requires three independent networks and costly custom equipment to accomplish the desired selectable distribution, the system also has the following disadvantages: a) the students cannot control the A/V sources; b) without adding expensive redundant circuitry in the analog A/V distribution unit, the prior art system cannot concurrently distribute multiple A/V materials to different combinations of student personal computers; c) the student personal computers are turned into passive "TV monitors" when A/V materials are distributed to them, making the student personal computers unavailable for other concurrent usages; d) the A/V materials are not capturable on the student personal computers as video and sound data inputs to other processing for learning purpose. The last disadvantage is particularly undesirable in view of the fact that the desired computer aided educational systems of the future are those that allow students to learn through active participation. Education experts have come to recognize that students learn best when they can construct their own knowledge to represent their understanding of a subject matter, using video, sound, as well as text. In U.S. Patent 4,920,432, a business system adapted for hotel and hospital usage is disclosed. A/V materials are selectably distributed from a number of A/V players/sources in an A/V library to a number of remote user terminals under the control of a system supervisor computer and the supervision of a master user terminal. The selectable A/V distribution is accomplished using two independent networks, a digital data communication network, and a multi-frequency analog A/V distribution network. In addition to standard personal computer equipment such as color graphics monitor, a typical user terminal is further equipped with a digital data communication network interface and a tuner. The master user terminal and the system supervisor computer are similarly constituted as the user terminals, except that they are not provided with tuners. Additionally, the master user terminal is provided with monitoring software such as accounting, and the system supervisor computer is provided with a control interface to the A/V equipment in the A/V library as well as control software for controlling the A/V equipment. Furthermore, the system is provided with an A V filer, an A/V device controller, and an analog A/V signal combiner. While the system requires one less independent network and less costly custom equipment to accomplish the desired distribution, the system still has the following disadvantages: a) the users still cannot control the A/V sources; b) the user personal computers are still essentially turned into passive "TV monitors" when A/V materials are distributed to them, although superimposing of messages is possible, making the personal computers substantially unavailable for other more interactive concurrent usages; c) the A/V materials are still not capturable by the users as video and sound data inputs to other processing. d) screen images cannot be shared between a "control" station and a user personal computer, nor can keystrokes be provided from the "control" station to a user personal computer. With the advent of multi-media computers, the industry trend is to provide systems with multi-media computers and digital A/V servers coupled to each other on a single digital data communication network. A/V materials are stored on the digital A/V servers in digitized form, and distributed through the digital data communication network. While these systems would overcome the disadvantages discussed above, these systems have the disadvantages of requiring the A/V materials to be available, stored, and distributed in digitized form, which typically also requires data compression and decompression at the transmission and receiving ends. Notwithstanding data compression, the volume of digital video and sound data that have to be transmitted would put a heavy burden on the digital data communication network. Most of all, these systems are relatively expensive today. As will be disclosed in more detail below, the present invention provides a cost effective approach to selectable A/V distribution to local and remote stations that advantageously achieves the above described and other desired results. SUMMARY OF THE INVENTION The desirable results are advantageously achieved by equipping a master control station as well as a number of local and/or remote stations with multi-media workstations having networking interfaces, multi-frequency analog video signal receivers, and various A/V software, and coupling these multi-media workstations to a number of A/V sources and each other via a multi-channel A/V network and a digital data network. Preferably, the multi-channel A/V network is a cable television (CATV) network. For an embodiment adapted for local area usage, such as a classroom or a cluster of close by offices, preferably the digital data network is an Ethernet network. In one embodiment, except for an modulated A/V source, each of the unmodulated A/V sources comprises an A/V device and a corresponding networkable modulator, coupled to each other. Additionally, the networkable modulators are serially coupled to each other with the last networkable modulator coupled to the head of the CATV network, and individually to the Ethernet network. In an alternate embodiment, standard modulators in conjunction with an A/V signal combiner and an A/V device controller are used instead. The modulated A/V sources and the standard modulators are connected to the A/V signal combiner which in turn is coupled to the head of the CATV network. The A/V devices are connected through corresponding interfaces to the A/V device controller which in turn is coupled to the master control multi-media workstation. For either embodiments, each of the stations is provided with a multi-media workstation having a high performance processor, A/V digitization and rendering circuitry, a high pixel density display, and speakers. Each of the multi-media workstations is also equipped with a CATV tuner and an Ethernet interface. Additionally, each of the multi¬ media workstations is equipped with an operating system having integrated network and A/V services, an A/V command handler module, and an A/V control module. Lastly, the multi-media workstation for the master control station is further equipped with a master A/V control module. Both the A/V control module and the master A/V control module include end-user interfaces for interacting with users of the multi¬ media workstations. Additionally, the A/V control module further includes a programming interface for interacting remotely with the master A/V control module, when the A/V control module is running on a multi-media workstation at a user station. During operation, the user at the multi-media workstation with the master A/V control module selectably controls the A/V devices remotely through the end-user interface of the A/V control module. In response, the A/V devices generate A/V outputs, which in turn are modulated as analog A/V signals onto the different channels of the CATV network. The CATV network delivers the analog A/V signals to the multi-media workstations. The user at the multi-media workstation with the master A/V control module further selectably controls the A/V rendering control selections to be used by the A/V control modules on the other multi-media workstation remotely, through the end-user interface of the master A/V control module. Accordingly, the A/V control modules on the other multi-media workstations control the A/V signal receptions by the analog video signal receivers, and A/V signal digitization and rendering on the displays and speakers by the A/V digitization and rendering circuitry on their respective multi-media workstations. Additionally, the user at the multi-media workstation with the master A/V control module may further selectably grant or revoke authorizations to access the A/V sources by users at the other multi-media workstations through the end-user interface of the master A/V control module. The users with granted authorization to access may further selectably control the A/V devices remotely through the end-user interfaces of the A/V control modules running on their respective multi-media workstations. Furthermore, the users at the other multi-media workstations may selectably control the A/V signals reception, digitization, and rendering at their respective multi-media workstations through the end-user interfaces of the A/V control modules on their respective multi-media workstations, provided the local control selections do not conflict with the remote control selections. In the event of conflicts, the remote control selections take precedent over the local control selections. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1a & 1b illustrate two embodiments of the network of A/V devices and multi-media workstations of the present invention. Figure 2 illustrates the relevant portions of the architecture of one embodiment of one of the multi-media workstations of Figures 1a & 1 b. Figure 3 illustrates the relevant software components on the multi-media workstations of Figures 1a & 1b. Figure 4 illustrates an exemplary screen image rendered on the display of Figure 2. Figure 5 illustrates some of the elements of one embodiment of the end user interface of the A/V control module of Figure 3. Figure 6 illustrates one of the elements of one embodiment of the end user interface of the master A/V control module of Figure 3. Figure 7 illustrates the method steps for selectable A/V distribution from the A/V devices to the multi-media workstations of Figures 1a & 1b. DETAILED DESCRIPTION In the following description for purposes of explanation, specific numbers, materials and configurations are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without the specific details. In other instances, well known systems are shown in diagrammatic or block diagram form in order not to obscure the present invention unnecessarily. Referring now to Figures 1a - 1b, two block diagrams illustrating two embodiments of the network of A/V devices and multi-media workstations of the present invention are shown. As illustrated, the network 10 comprises a number of multi-media workstations 12 and 14, and a number of A/V sources 16. The multi-media workstations 12 and 14 are coupled to the A/V sources 16 and each other via a multi-channel A/V network 18, and a digital data network 20. Optionally, the network 10 may further comprise a number of other A/V presentation stations 22, which are also coupled to the multi-channel A/V network 18 and the digital data network 20. It is contemplated that the multi-media workstations 12 and 14 are provided to a master control station and a number of local or remote individual user stations, whereas the optional A/V presentation stations 22 are provided to multi-user stations. For some applications, such as computer aided classroom instruction, the multi-media workstations 12 and 14 are provided to a teacher and a number of individual student stations, and together with the A/V sources 16 and the optional A/V presentation stations 22 all located close to each other in the same or adjacent classrooms. On the other hand, for other applications, such as a business research and development facility, the multi-media workstations 12 and 14 are provided to a control station and a number of engineering/programming stations, and including the A/V sources 16 as well as the optional A/V presentation stations 22 all dispersed in remote offices and/or conference rooms throughout the facility. Users perform computing and selectably receive A/V materials using their multi-media workstations 12 and 14. As will be described in further detail below, each of the multi-media workstations 12 and 14 is equipped to selectably control the generation of the A/V materials by the A/V sources 16, as well as selectably control the reception and rendering of the A/V materials on the workstation itself. The multi-media workstation 12 provided to the master control station is further equipped to selectably control the reception and rendering of A V materials on the multi¬ media workstations 14 and the optional A/V presentation stations 22. The digital data network 20 delivers data including commands from the multi-media workstations 12 and 14 to the A/V sources 16, between the multi-media workstations 12 and 14, and from the master control station's multi-media workstation 12 to the optional presentation stations 22. In an embodiment adapted to local area application, preferably the digital data network 20 is an Ethernet network. The A/V sources 16 responsive to the controls of the multi¬ media workstations 12 and 14 generate and modulate the A/V materials as analog A/V signals onto the different channels of the multi-channel A/V network 18. Depending on the implementation, the channel onto which an A/V source 16 is to modulate its generated analog A/V signals may be predetermined or under remote control from the multi-media workstations 12 and 14. As illustrated in the presently preferred embodiment in Figure 1a, the A/V sources 16 comprise a number of A/V device 24, and a number of corresponding networkable modulators 26. Optionally, the A/V sources 16 may further comprise a modulated A/V source 25 and a corresponding filter amplifier combination 27. Each A/V device 24 is coupled to its corresponding networkable modulator 26. The networkable modulators 26 are serially coupled to each other with the last of the networkable modulators 26 coupled to the head of the multi-channel network 18. The networkable modulators 26 are also individually coupled to the digital data network 20. The optional filter amplifier combination 27 is coupled to the first of the networkable modulators 26. Preferably, each A/V device 24 is coupled to provide the corresponding networkable modula.or 26 with its analog A/V output- as well as to receive commands originated from the multi-media workstations 1 ? and 14 from its netwo r kable modulator 26. An A/V device 24 not coupled to receive commands from its networkable modulator 26 may be operated manually. In addition to the analog A/V outputs received from its corresponding A/V device 24, the first networkable modulator 26 also receives the modulated analog A/V signals on various frequencies from the modulated A/V source 25. The first networkable modulator 26 modulates the analog A/V outputs received from its corresponding A/V device 24 onto a predetermined or remotely instructed unused frequency and combining them with the other modulated analog A/V signals before outputting them. Similarly, each subsequent networkable modulator 26 receives the analog A/V outputs from its corresponding A/V device 24, and modulated analog A/V signals on various frequencies from its predecessor networkable modulator 26. In like manner, each subsequent networkable modulator 26 modulates the analog A/V output received from its corresponding A/V device 24 onto a predetermined or remotely instructed unused frequency and combine • them with the other modulate- analog A/V signals before outputting them. Thus, the analog A/V signals on the various frequencies are placed onto the multi-frequency network 18. Particular examples of A/V devices 24 include but not limited to video cameras, video cassette recorders (VCRs), and video disc players (VDP) known in the art, modified with an interface to accept commands from the networkable modulators 26. The networkable modulators 26 may be implemented with modulators known in the art, modified to incorporate a digital data network interface for connection to the digital data network 20 and an interface for connecting to the A/V device 24. Particular examples of a modulated A/V source 25 includes but not limited to a television (TV) antenna, a satellite TV dish, and a cable TV provider. Particular examples of an A V presentation station 22 include but not limited to an A/V projector. As illustrated in the alternate embodiment in Figure 1 b, standard modulators 28 in conjunction with an A/V signal combiner 30 and an A/V device controller 32 may be used in lieu of networkable modulators 26. The modulated A/V source 27 and the standard modulators 28 are connected to the A/V signal combiner 30 which in turn is coupled to the multi-channel network 18. Additionally, the A/V devices 24 are preferably connected through corresponding interfaces to the A/V device controller 32 which in turn is coupled to the master control station's multi-media workstation 12. A particular example of the standard modulators 28 is the A/V modulator, model #VM2552, manufactured by R.L Drake Co., Miamisburg, Ohio. A particular example of the A/V signal combiner 30 is the A/V signal combiner, model OC-12, manufactured by Olson Technology, Inc., Sierra Village, Ca. A particular example of the A/V device controller 32 is the A/V device controller ALIX, manufactured by VideoMedia, San Jose, Ca. The multi-channel A/V network 18 delivers the analog A/V signals from the A/V sources 16 to the multi-media workstation? 12 and 14, and the optional A V presentation stations 22. Preferably, t e multi¬ channel A/V network 18 is a CATV network. The embodiment illustrated in Figure 1a has more flexibility in that it allows users at the multi-media w r kstations 12 and 14 to dynamically change the frequencies on which the networkable modulators 26 modulate the outputs of the A/V devices 24. However, the embodiment illustrated in Figure 1b is probably less costly and simpler to implement. Additionally, while both embodiments illustrate the master control station as being also provided with a multi-media workstation, based on the descriptions to follow, it will be appreciated that the present invention may be practiced without the master control station being provided with the capability of digitizing analog A/V signals into digitized video and sound data. Referring now to Figure 2, a block diagram illustrating the relevant portions of the architecture of one embodiment of the teacher and student multi-media workstations 12 and 14 is shown. As illustrated, in this embodiment, each of the multi-media workstations 12 and 14 comprises a central processing unit (CPU) 100, A/V digitization circuitry 102, read only memory (ROM) 104, random access memory (RAM) 106, video memory (VRAM) 108, and a number of permanent storage devices 110. Additionally, each of the multi-media workstations 12 and 14 comprises a system bus 128, an A/D and D/A converter 130, a digital data network interface 116, a multi-channel analog A/V signal receiver 118, and a display controller 124. Furthermore, each of the multi-media workstations 12 and 14 comprises a keyboard 112, a cursor control device 114, a microphone 120, speakers 122, and a display 126. These elements 100 - 130 are coupled to each other as shown. The CPU 100 and the A/V digitization and rendering circuitry 102 are preferably high performance processor and circuitry complemented with memories 104 - 108 of sufficiently large capacity to support high performance and high volume processing of multi-media data for rendering of TV-like full motion picture image sequences on the display 126 and high quality sound on the speakers 122. The storage devices 120 preferably include a hard disk and a CD-ROM drive. For an embodiment adopted for local area application, the digital data network interface 116 is preferably an Ethernet interface. The multi-channel analog signal receiver 130 is preferably a CATV tuner. The speakers 122 preferably include a pair of stereo speakers and headphone connectors. The display 126 preferably is a high density pixel display, and the display controller 124 is complementarity adapted. The multi-channel analog signal receiver 130 receives analog A/V signals from one of the channels of the multi-channel network 18. The A/D and D/A converters 130 digitizes the received analog audio signals into digitized audio data, and stores the digitized audio data into the RAM 106. The A/V digitization and rendering circuitry 102 digitizes the received analog video signals into digitized video data, and stores the digitized video data into the VRAM 108. The stored digitized audio data are rendered as sound on the speakers 122 through the A/D and D/A converter 130 under program control. The stored digitized video data are rendered as TV-like full motion picture image sequence on the display 126 through the display controller 124 under program control. In the presently preferred embodiment, the digitized audio and video c . are stored into the RAM 106 and VRAM 108 cumulatively, and the stored audio and video data are rendered as sound on the speakers 122, and TV-like full motion picture image sequence on the display 126 real time. A particular example of a multi-media workstation comprising these elements 100 - 130 is the Quadra 660 A/V computer manufactured by Apple Computer, Inc. of Cupertino, Ca. (hereinafter as Apple), modified to include the multi-channel analog signal receiver 118. Alternatively, the multi-media workstation 12 or 14 may be implemented with a Macintosh LC computer, also manufactured by Apple, enhanced to include the speakers 122, the multi-channel analog A/V signal receiver 118, as well as a peripheral card having the A/V digitization circuitry 102. The multi-channel analog signal receiver 118 may be implemented with any number of multi-channel analog signal receivers known in the art, modified to complement the particular implementations of the multi-channel A/V network 18 and the other elements 100 - 130 of the multi-media workstations 12 and 14. Referring now to Figure 3, a block diagram illustrating the relevant software components on the multi-media workstations 12 and 14 is shown. As illustrated, each of the multi-media workstations 12 and 14 is equipped with an operating system having integrated network and A V services 200, an A/V command handler module 202 and an A/V control module 206. The master control station's multi-media workstation 12 is further equipped with a master A/V control module 210. As will be described in further detail below, both the A/V control module 206 and the master A/V control module 210 include end- user interfaces for interacting with users at the multi-media workstations 12 and 14. Additionally, the A/V control module 206 further comprises a programming interface for interacting remotely with the master A/V control module 210 when running on user stations' multi-media workstations 14. In addition to the A/V services necessary to control the A/V digitization circuitry 102, and the display control 124, preferably the operating system 200 includes A/V services for capturing digitized audio and video data as inputs for other processing, such as video editing, or creating a multi-media report. A particular example of an operating system having integrated network and A/V services is System 7 (including the Quicktime system extension) designed for the Macintosh computers developed by Apple. The A/V command handler module 202 takes the commands generated by the A/V control module 206 and the master A/V control module 210, formulates them into data packets adapted for transmission by the underlying operating system network services 200 over the digital data network 20, and calls the operating system network services 200 to transmit them. The generated commands may be directed to all or selected ones of the nodes of the network. A node may be a multi-media workstation 12 and 14, one of the A/V sources 16, or one of the optional A/V presentation stations 22. The A/V command handler module 202 may be implemented in any number of programming languages and techniques similar to many low level data communication handlers found in other applications. The implementation is dependent on the functions to be supported by the A/V command handler module 202, and the network services provided by the underlying operating system 200. For further information on network services supported by System 7, see Inside Macintosh, Vol I - VI, published by Addison Wesley, 1985 - 1991. The A/V control module 206 responsive to a user's interactions with its end user interface generates commands directing the multi-channel analog A/V signal receiver 118 on its multi-media workstation 12 and 14 to receive analog A/V signals from one of the channels of the multi-channel network 18. The A/V control module 206 responsive to the user's interactions with its end user interface further generates commands directing the A/D and D/A converter 130 and the A/V digitization circuitry 102 on its multi-media workstation 12 and 14 to digitize the received analog audio and video signals into digital audio data and digital video data with particular scaling, horizontal and vertical filtering respectively. Lastly, the A/V control module 206 responsive to the user's interactions with its end user interface further generates commands directing the A/D and D/A converter 130 and the display controller 124 to render the digitized audio data as sound on the speakers 122 having particular audio characteristics, and the digitized video data as TV-like full motion image sequence on the display 125 having particular video characteristics. The A/V control module 206 further performs the above described functions responsive to remote commands received from the master A/V control module over the digital data network 20 through the A/V command handler modules 202 and the operating systems 200 on the respective multi-media workstations 12 and 14. In the event that the remote commands conflict with the user interactions, the remote commands take precedence over the user interactions. Preferably, the A/V control module 206 responsive to remote commands further disables incompatible user control selections in its end user interface. Additionally, the A/V control module 206 responsive to the user's interactions with its end user interface further generates commands directing the remote A/V sources 16 to generate and modulate A/V - aterials as A/V analog signals on various frequencies on the multi-channel A/V network 18, when the A/V control module 206 is granted authorization to access the A/V sources 16, thereby allowing the users at the other multi-media workstations 14 to directly control the A/V sources 16. Preferably, the A/V control supported includes but not limited to starting, stopping, forwarding, rewinding an A/V title. The A/V control module 206 may be implemented in any number of programming languages and technique similar to many control modules found in other applications. Except for the programming interface, acceptance of remote commands through the programming interface, the prioritization of these remote commands over local user interactions, the dependency of the available user actions on the end user interface on the remote commands, and remotely controlling the A/V sources, the basic functions of the A/V control module 206 is known to have been implemented for at least the MacTV product manufactured by Apple. Implementation of the noted additional functionalities is well within the ability of those skilled in the art. Thus, except for the manner in which the A/V control module 206 cooperates with other elements under the teachings of the present invention, the A/V control module 206 will not be otherwise further described. The master A/V control module 210 responsive to a user's interactions with its end user interface generates commands directing the remote A/V sources 16 to generate and modulate A/V materials as A/V analog signals on various frequencies on the multi-channel A/V network 18. Preferably, the control supported includes but not limited to the starting, stopping, forwarding, and rewinding of an A/V title. The master A/V control module 210 responsive to the user's interactions with its end user interface further generates commands directing the A/V control modules 206 on other multi-media workstations 12 and 14 as to how to direct the multi-channel analog A/V signal receivers 118, the A/D and D/A converters 130, the A/V digitization crijitry 102, and the display controllers 124 on these multi-media workstations 12 and 14 to receive analog A/V signals from one of the channels of the multi-channel network 18, to digitize the received analog audio and video signals into digital audio data and digital video data, to render the digitized audio and video data as sound and TV- like full motion image sequence on the speakers 122 and the display 125. Preferably, the master A/V control module 210 responsive to the user's interactions with its end user interface further generates commands granting or revoking access to the A/V sources 16 to selected ones of the other multi-media workstations 14. The master A/V control module 210 may be implemented in any number of progr -ming languages and techniques similar to many remote control modules found in other applications. The ir ementation is dependent on the functions supported by the master A/V control module 210. Still referring to Figure 3, as illustrated, in this embodiment, in addition to the A/V services provided by the operating system 200, each of the multi-media workstations 12 and 14 is further provided with an audio distribution module 204, and a number of A/V applications 208. The audio distribution module 204, when running on the master control station's multi-media workstation 12, responsive to commands generated by the master A/V control module 210 generates commands for the audio services of the operating system 200, directing the network and audio services to establish channels of audio communications between the master control station's multi-media workstation 12 and selected ones of the other multi-media workstations 14. Additionally, the audio distribution module 204 on an audibly connected multi-media workstation 12 and 14 causes audio data digitized from analog audio inputs received from the microphone 120 to be packaged and transmitted to the appropriate ones of the other multi-media workstations 12 and 14 over the digital data network 20. Furthermore, the audio distribution module 204 on an audibly connected multi-media workstation 12 and 14 causes the digitized audio data received over the digital data network 20 to be rendered on the speakers 122. The audio distribution module 204 may be implemented in any number of programming languages and techniques similar to many low level sound handlers found in other applications. The implementation is dependent on the functions to be supported by the audio distribution module 204, and the audio services provided by the underlying operating system 200. For further information on audio services supported by System 7, see Inside Macintosh, Vol I - VI, published by Addison Wesley, 1985 - 1991. The A/V applications 208 include an A/V application for screen sharing, and one multi-media workstation 12 providing >ts keystroke and cursor control inputs to another multi-media workstation 14 over the digital data network 20 through the network services of the underlying operating system 200. A particular example of such an A/V ar tion is the Timbuktu product developed by Farallon Computing, Inc., oτ Aiameda, Ca. The master A/V control module 210 responsive to the user's interactions with its end user interface further generates commands for the audio distribution module 204 and the A/V applications 208, causing these module/application 204 and 208 to establish and effectuate audio communication with all or selected ones of the other multi-media workstations 14, to show the current screen content rendered on its multi¬ media workstation's display 126 on the displays 126 of selected ones of the other multi-media workstations 14, to show the screen images being rendered on the display 126 of a selected one of the other multi-media workstations 14 to be shown on its multi-media workstation's display 126, and to provide the input keystrokes and cursor controls from its multi-media workstation's keyboard 112 and cursor control 114 to selected ones of the other multi-media workstations 14. Additionally, the A/V control module 206 responsive to the user's interactions with its end user interface further generates commands for the video capturing services of the operating system 200 causing the digitized video data to be captured into a data file, which in turn can be used as inputs to a variety of other processing. Referring now to Figure 4, a diagram illustrating an exemplary screen image rendered on the display 124 of Figure 2 is shown. As illustrated, the screen image 300 comprises a number of resizable display windows 302 - 306 for displaying information for different programs. For the exemplary screen image 300 illustrated, one of the display window 302 is used to render the digitized video data as TV- like full motion image sequence. The other two display windows 304 and 306 are used to display information for the operating system 200. As illustrated by the display window 306, the user can continue to interact with an application or the operating system, while the digitized video data are being rendered as TV-like full motion image sequence. Thus, under the present invention, the multi-media workstations 12 and 14 remain active and useable when A/V materials are selectably distributed to them. Referring now to Figure 5, a diagram illustrating some of the elements of one embodiment of the end user interface of the A/V module 206 is shown. As illustrated, the end user interface 310 comprises a video control window 310 and an audio control window 312. Additionally, the end user interface 310 comprises the video displε /indow 302 illustrated in Figure 4. Furthermore, in this embodiment, the end user interface 310 comprises an A/V device control window 314 and an A/V capture control window 316. The windows 302, and 310 - 316 are selectively displayed depending on the received remote commands, and the local user interactions with the end user interface 308 of the A/V control module 206. The image display window 302 (see Fig. 4) is resizable and includes icons for a user to change channel and audio volume. As described earlier, responsive to interactions with these icons, the A/V control module 206 generates appropriate commands for the A/V digitization circuitry 102, the display controller 124, and the A/D and D/A converter 130. The video control window 310 includes icons for a user to select the video type, change the brightness, sharpness, and tint of the video images, etc. As described earlier, responsive to interactions with these icons, the A/V control module 206 generates appropriate commands for the display controller 124. The audio control window 312 includes icons for a user to select the audio type, change the balance, bass, and treble of the sound rendered, etc. As described earlier, responsive to interactions with these icons, the A/V control module 206 generates appropriate commands for the A/D and D/A converter 130. The A/V device control window 314 includes icons for a user to control an A/V source 16, such as playing an A/V title, stop playing an A V title, fast forwarding, etc. As described earlier, responsive to interactions with these icons the A/V control module 206 generates appropriate commands for the A/V command handler module 202 to format and forward to the A/V source 16 through the operating system 200 and the digital data network 20. The A/V capturing control window 314 includes icons for a user to control capturing of digitized video and sound data. As described earlier, responsive to interactions with the icons, the A/V control module 206 generates appropriate commands for the A/V capturing application 208. The end user interface 308 may be implemented with any number of programming languages and techniques. The implementation is dependent on the amount of control functions supported. As will be appreciated, in addition to the control functions illustrated, the end user interface 308 of the A/V control module 206 may support a variety of other control functions. For further information on implementing windowed graphical end user interface under System 7, see also Inside Macintosh, Vol I - VI, published by Addison Wesley, 1985 - 1991. Referring now to Figure 6, a diagram illustrating one of the eleme ts of one embodiment of the end user interface of the master A/V control module 210 is shown. As illustrated, the end user interface 320 comprises a base control window 322. The base control window 322 includes a "show video" icon and related dialog boxes (not shown) for a user to instruct all or selected ones of the other multi-media workstations 14 and the optional presentation stations 22 to receive analog video signals of an A/V materials off a particular channel of the multi-channel A/V network 18. As described earlier, responsive to interactions with the icon and its related dialog boxes, the master A/V control module 210 generates appropriate commands for the A/V command modules 206 at the selected multi-media workstations 14 through the A V command handler modules 202, the operating systems 200, and the digital data network 20. The base control window 322 further includes a "show screen" icon, a "control" icon, and their related dialog boxes (not shown) for a user to show his/her screen content, and provide his/her keystrokes/cursor controls to all or selected ones of the other multi-media workstations 14. As described earlier, responsive to interactions with these icons and their related dialog boxes, the master A/V control module 210 generates commands for one of the A/V application 208 on its multi-media workstation 12, which in turn cooperates with the A/V applications 208 on the selected multi-media workstations 12 to accomplish the desired results. The base control window 322 further includes an "observe" icon and its related dialog boxes (not shown) for a user to observe the screen content of a selected one of the other multi-media workstations 14. As described earlier, responsive to interactions with the icon and its related dialog boxes, the master A/V control module 210 generates commands for one of the A/V application 208 on its multi-media workstation 12, which in turn cooperates with the A/V applications 208 on the selected multi-media workstations 12 to accomplish the desired results. The base control window 322 further includes an "announce" icon, a "talk" icon, and their related dialog boxes (not shown) for a user to establish and conduct audio communication with all or selected ones of the other multi-media workstations 14. As described earlier, responsive to interactions with these icons and their related dialog boxes, the master A/V control module 210 generates commands for the A/V audio distribution module 204 on its multi-media workstation 12, which in turn cooperates with the A/V distribution module 204 on the selected multi-media workstations 12 to accomplish the desired results. Lastly, the base control window 322 further includes a "grant" icon (not shown) and related dialog boxes (also not shown) for a user to grant or revoke authorization to access particular A/V sources 16. . As described earlier, responsive to interactions with the icon and its related dialog boxes, the master A/V control module 210 generates appropriate commands for the A/V command modules 206 at the selected multi-media workstations 14 through the A/V command handler modules 202, the operating systems 200, and the digital data network 20. The end user interface 320 may be implemented with any number of programming languages and techniques. The implementation is dependent on the amount of control functions supported. As will be appreciated, in addition to the basic control functions illustrated, the end user interface 320 of the master A V control module 210 may support a variety of other control functions also. Referring now to Figure 7, a block diagram illustrating the method steps for selectable A/V distribution to local or remote station is shown. As illustrated, during operation, the users selectably control the A/V devices 24 remotely through the end-user interfaces 308 of the A/V control modules 206 running on their respective multi-media workstations 12 and 14, step 402. As described earlier, the users at the other multi¬ media workstations 14 may selectably control the A/V devices 24 if they are granted authorization to access these A/V devices 24 by the user at the multi-media workstation 12 provided to the master control station. Responsive to these user actions, the A/V control modules 206 generate A/V commands which are routed to the A/V devices 24 through the A/V command handler modules 202, the operating systems 200, and the digital data network 20. In response, the A/V devices 24 generate A/V outputs, which in turn are modulated onto the different channels of the multi-channel network 18, step 404. The multi-channel network 18 delivers the analog A/V signals to the multi-media workstations 12 and 14. The users control the A V signals reception, their digitization and rendering on their respective multi-media workstations 12 and 14 through the end-user interfaces 308 of the A/V control modules 206 running on their respective multi-media workstations 12 and 14, step 406. Additionally, the user at the multi-media workstation 12 provided to the master control station may further selectably override the A/V control selections made by a user at one of the other multi-media workstations 14 through the end user interface of the master A/V control module 210. The A/V control module 206 sets the multi-channel analog A V signal receiver 118 on its multi-media workstation 12 or 14 to the appropriate channel, causes the A/D and D/A converter 130 and the A/V digitization circuitry 102 to digitize the analog audio and video signals into digital audio and video data, and the A/D and D/A converter 130 and the display controller 124 to render the digital audio and video data sound on the speakers and TV-like full motion picture image sequence in a resizable window on the display 126 of the multi-media workstation 12 or 14 accordingly, step 408. While the present invention has been described in terms of presently preferred and alternate embodiments, those skilled in the art will recognize that the invention is not limited to the embodiments described. The method and apparatus of the present invention can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is thus to be regarded as illustrative instead of limiting on the present invention.

Claims: WHAT IS CLAIMED IS 1. An apparatus for selectable audio/video (A/V) delivery to at least one multi-media workstation comprising: a) an A/V source for generating and modulating a first A/V material as a first stream of analog A/V signals on a first frequency channel; b) an A/V network coupled to said A/V source for conveying said first stream of analog A/V signals on said first frequency channel; c) a first multi-media workstation comprising a first analog A/V signal receiver coupled to said A/V network for receiving said first stream of analog A/V signals off said first frequency channel in response to first A/V rendering control commands, said first multi-media workstation further comprising a first A/V control module for providing said first analog A/V signal receiver with said first A/V rendering control commands in response to second A/V rendering Dntrol commands that are selectably provided, said first multi-media workstation in real time digitizing said first stream of analog A/V signals into a first stream of digital A/V data and rendering said first stream of digital A/V data as video images and sound on said first multi¬ media workstation; d) a digital data network coupled to said first multi-media workstation for conveying said select: y provided second A/V rendering control commands to said first multi-media workstation; and e) a remote A/V distribution controller coupled to said digital data network comprising a second A/V control module for selectably providing said second A/V rendering control commands and placing them onto said digital data network. 2. The apparatus as set forth in claim 1 , wherein, said A/V source comprises: (a.1 ) a first A/V device responsive to first A/V generation control commands selectably provided by said second A/V control module of said remote A/V distribution controller for generating said first A V material as said first stream of analog A/V signals; and (a.2) a first modulator coupled to said digital data network, said first A/V device, and said A/V network for routing said first A/V generation control commands from said remote A/V distribution controller to said first A/V device, and for modulating said first stream of analog A/V signals onto said A/V network on said first frequency channel, said first A/V control commands being provided to said first modulator through said digital data network. 3. The apparatus as set forth in claim 2, wherein said A/V source further comprises: (a.3) a second A/V device responsive to second A/V generation control commands selectably provided by said second A/V control module of said remote A/V distribution controller for generating a second A/V material as a second stream of analog A/V signals; and (a.4) a second modulator coupled to said digital data network, said second A/V device, and said A/V network for routing said second A/V generation control commands from said remote A/V distribution controller to said second A/V device, and for modulating said second stream of analog A/V signals onto said A/V network on a second frequency channel, said second A/V generation control commands being provided to said second modulator through said digital data network. 4. The appr "tus as set forth in claim 1 , wherein, said A/V i.atwork is a cable television (CATV) network; said first analog A/V signal receiver is a CATV tuner; and said first multi-media workstation render said video images and sound in a format and at a sufficiently fast rate such that said first A/V material appear like full motion television picture with corresponding sound track to a viewer at said second multi-media workstation. 5. The apparatus as set forth in claim 1 , wherein, said local area data network is an Ethernet network; and each of said remote A/V distribution controller and first multi-media workstations comprises an Ethernet interface. 6. The apparatus as set forth in claim 1 , wherein said apparatus further comprises: f) a second multi-media workstation comprising a second analog A/V signal receiver coupled to said A/V network for receiving said first stream of analog A/V signals off said first frequency channel in response to third A/V rendering control commands, said second multi-media workstation further comprising a third A/V control module for providing said second analog A/V signal receiver with said third A/V rendering control commands in response to fourth A/V rendering control commands that are selectably provided, said second multi-media workstation in real time digitizing said first stream of analog A/V signals into a first stream of digital A/V data and rendering said first stream of digital A/V data as video images and sound on said second multi-media workstation. 7. The apparatus as set forth in claim 1 , wherein said remote A/V distribution controller is a second multi-media workstation. 8. A computer implemented method for selectable audio/video (A/V) delivery to at least one multi-media workstation, said method comprising the steps of: a) generating a first A/V material as a first stream of A/V analog signals, and modulating said first stream of A/V signals onto a first frequency channel of an A/V network using an A V device connected to the A/V network; b) remotely and selectably generating first A/V rendering control commands, and placing said first A/V rendering control commands onto a digital data network using a remote A/V distribution controller connected to said digital data network; c) receiving said first stream of A/V analog signals off said first frequency channel, digitizing said received first stream of analog A/V signals into a first stream of digital video and audio data, and rendering in real time said first stream of digital video and audio data as video images and sound, in accordance to said selectably generated first A/V rendering control commands, using a first multi-media workstation connected to said A/V network and said digital data network. 9. The method as set forth in claim 8, wherein, said step (a) further comprises remotely and selectably generating first A/V generation control commands, and placing said first A/V generation control commands onto said digital data network, using said remote A/V distribution controller; said A/V device being also connected to said digital data network generates said first A/V material as said first streams of analog A/V signals, and modulate said first stream of analog A/V signals onto said first frequency channel in accordance to said selectably generated first A/V generation control commands. 10. The method as set forth in claim 8, wherein, said step a) further comprises generating a second A/V material as a second stream of A/V analog signals, and modulating said second stream of A/V signals onto a second frequency channel of said A/V network using said A/V device; said step b) further comprises remotely and selectably generating second A/V rendering control commands, and placing said second A/V rendering control commands onto said digital data network using said remote A/V distribution controller; said step c) further comprises receiving said second stream of A/V analog signals off said second frequency channel, digitizing said received second stream of analog A/V signals into a second stream of digital video and audio data, and rendering in real time said second stream of digital video and audio data as video images and sound, in accordance to said selectably generated second A/V rendering control commands, using a second multi-media workstation connected to said A/V network and said digital data network. 11. A computer aided instruction system comprising: a) an A/V source for generating and modulating a first A/V material as a first stream of analog A/V signals on a first frequency channel; b) an A/V network coupled to said A V source for conveying said first stream of analog A/V signals on said first frequency channel; c) a first student multi-media workstation comprising a first analog A/V signal receiver coupled to said A/V network for receiving said first stream of analog A/V signals off said first frequency channel in response to first A/V rendering control commands, said first student multi-media workstation further comprising a first A/V contra module for providing said first analog A/V signal receiver with said first A/V rendering control commands in response to second A/V rendering control commands that are selectably provided, said first student multi-media workstation in real time digitizing said first stream of analog A/V signals into a first stream of digital A/V data and rendering said fir * stream of digital A/V data as video images and sound on said first student multi-media workstation; d) a digital data network coupled to said first student multi-media workstation for conveying said selectably provided second A/V rendering control commands to said first student multi-media workstation; and e) a teacher station coupled to said digital data network comprising a second A/V control module for selectably providing said second A/V rendering control commands and placing them onto said digital data network. 12. The computer aided instruction system of claim 11 , wherein, said first A/V source generates and modulates said first A/V material as said first stream of analog A/V signals onto said first frequency channel in response to first A/V generation control commands that are selectably provided; said second A/V control module of said teacher station further selectably generates said first A/V generation control commands; and said digital data network further couples said first A/V source to said teacher station for delivering said first A/V generation control commands from said teacher station to said first A/V source. 13. The computer aided instruction system of claim 11 , wherein, said system further comprises: f) a second A/V source coupled to said A/V network for generating and modulating a second A/V material as a second stream of analog A/V signals onto a second frequency channel on said A/V network; g) a second student multi-media workstation comprising a second analog A/V signal receiver coupled to said A/V network for receiving said second stream of analog A/V signals off said second frequency channel in response to third A/V rendering control commands, said second student multi-media workstation further comprising a third A/V control module for providing said second analog A/V signal receiver with said third A/V rendering control commands in response to fourth A/V rendering control commands selectably provided by said second A/V control module of said teacher station, said second student multi-media workstation in real time digitizing said second stream of analog A/V signals into a second stream of digital A/V data and rendering said second stream of digital A/V data as video images and sound on said ε?cond student multi-media workstation. 14. An audio video (A/V) system comprising: a) an A/V source for generating and modulating a first A/V material as a first stream of analog A/V signals on a first frequency channel; b) an A/V network coupled to said A/V source for conveying said first stream of analog A/V signals on said first frequency channel; c) a first A/V station comprising a first analog A/V signal receiver coupled to said A/V network for receiving said first stream of analog A/V signals off said first frequency channel in response to first A/V rendering control commands, said first A/V station further comprising a first A/V control module for providing said first analog A/V signal receiver with said first A/V rendering control commands in response to second A/V rendering control commands that are selectably provided, said first A/V station in real time digitizing said first stream of analog A/V signals into a first stream of digital A/V data and rendering said first stream of digital A/V data as video images and sound on said first A/V station; d) a digital data network coupled to said first A/V station for conveying said selectably provided second A/V rendering control commands to said first A/V station; and e) a master station coupled to said digital data network comprising a second A/V control module for selectably providing said second A/V rendering control commands and placing them onto said digital data network. 15. The A/V system of claim 14, wherein, said first A/V source generates and modulates said first A/V material as said first stream of analog A/V signals onto said first frequency channel in response to first A/V generation control commands that are selectably provided; said second A/V control module of said master station further selectably generates said first A/V generation control commands; and said digital data network further couples said first A/V source to said master station for delivering said first A/V generation control commands from said master station to said first A/V source. 16. The A/V system of claim 14, wherein, said system further comprises: f) a second A/V source coupled to said A/V network for generating and modulating a second A/V material as a second stream of analog A/V signals onto a second frequency channel on said A/V network; g) a second A/V station comprising a second analog A/V signal receiver coupled to said A/V network for receiving said second stream of analog A/V signals off said second frequency channel in response to third A V rendering control commands, said second A/V station further comprising a third A/V control module for providing said second analog A/V signal receiver with said third A/V rendering control commands in response to fourth A/V rendering control commands selectably provided by said second A/V control module of said master station, said second A/V station in real time digitizing said second stream of analog A/V signals into a second stream of digital A/V data and rendering said second stream of digital A V data as video images and sound on said second A/V station.

Inventors: BUTAH JON D, DOYLE MARK T, GLASS STEVEN E, BUTAH, JON, D., DOYLE, MARK, T., GLASS, STEVEN, E.
Applicants: APPLE COMPUTER, APPLE COMPUTER, INC.
Application year: 1995
Main classification: H04N7
IPC codes: G06F3, G06F19, G06Q30, G06Q50, G09B5, H04L29, H04N7