Media dependent module interface for computer-based conferencing system

What is claimed is:

1. A media dependent module for a computer-based conferencing system, wherein:

the media dependent module provides an interface between an upper-level conferencing driver of the conferencing system and a lower-level communications driver of the conferencing system to isolate the conferencing driver from the communications driver;

the media dependent module is dependent upon hardware of the communications driver; and

the media dependent module is adapted to perform a plurality of functions called by the conferencing driver, wherein the plurality of functions comprises:

a first function for preparing the media dependent module for a conferencing session;

a second function for requesting a connection to a remote conferencing node;

a third function for accepting an incoming connection request;

a fourth function for rejecting the incoming connection request;

a fifth function for initiating a listen mode on an established connection;

a sixth function for closing the established connection;

a seventh function for ending the conferencing session;

an eighth function for retrieving information about the media dependent module;

a ninth function for verifying that a link packet of a specified size can be sent on the established connection: and

a tenth function for sending the link packet on the established connection; wherein:

the first function is an MDM.sub.-- BeginSession function;

the second function is an MDM.sub.-- MakeConnection function;

the third function is an MDM.sub.-- AcceptConnection function;

the fourth function is an MDM.sub.-- RejectConnection function;

the fifth function is an MDM.sub.-- Listen function;

the sixth function is an MDM.sub.-- CloseConnection function;

the seventh function is an MDM.sub.-- EndSession function;

the eighth function is an MDM.sub.-- GetCharacteristics function;

the ninth function is an MDM.sub.-- ClearToSend function; and

the tenth function is an MDM.sub.-- Send function.

2. The media dependent module of claim 1, wherein the media dependent module comprises a connection state machine.

3. The media dependent module of claim 2, wherein the connection state machine comprises:

(a) an initialization state;

(b) an in-session state;

(c) a connection out state;

(d) a connection in state; and

(e) a connected state.

4. The media dependent module of claim 3, wherein:

calling the first function changes the initialization state-to the in-session state;

calling the second function changes the in-session state to the connection out state;

receiving a connection accepted message from the remote conferencing node changes the connection out state to the connected state;

receiving a connection request message from the remote conferencing node changes the in-session state to the connection in state;

calling the third function changes the connection in state to the connected state;

calling the fourth function changes the connection in state to the in-session state;

calling the sixth function changes the connected state to the in-session state; and

calling the seventh function changes the in-session state to the initialization state.

5. The media dependent module of claim 4, wherein calling any of the fifth, eighth, ninth, and tenth functions leaves the connection state machine unchanged.

6. The media dependent module of claim 1, wherein:

the first function returns synchronously;

in response to the second function, the media dependent module sends one of a connection-established callback and a connection-rejected callback to the conferencing driver and the media dependent module sends a connection-requested callback to the remote conferencing node;

in response to the third function, the media dependent module sends the connection-established callback to the conferencing driver and the media dependent module sends the connection-established callback to the remote conferencing node;

in response to the fourth function, the media dependent module sends the connection-rejected callback to the remote conferencing node;

in response to the fifth function, the media dependent module sends the connection-requested callback to the conferencing driver;

in response to the sixth function, the media dependent module sends a connection-close-complete callback to the conferencing driver and a connection-close-notify callback to the remote conferencing node;

in response to the seventh function, the media dependent module sends a session-closed callback to the conferencing driver; and

in response to the tenth function, the media dependent module sends a send-complete callback to the conferencing driver and the media dependent module sends a data-receive callback to remote conferencing node.

7. A media dependent module for a computer-based conferencing system, wherein:

the media dependent module provides an interface between an upper-level conferencing driver of the conferencing system and a lower-level communications driver of the conferencing system to isolate the conferencing driver from the communications driver;

the media dependent module is dependent upon hardware of the communications driver: and

the media dependent module comprises a connection state machine, wherein the connection state machine comprises:

an initialization state;

(b) an in-session state;

(c) a connection Out state;

(d) a connection in state; and

(e) a connected state, wherein the media dependent module is adapted to perform a plurality of functions called by the conferencing driver, wherein the plurality of functions comprises:

an MDM.sub.-- BeginSession function for preparing the media dependent module for a conferencing session;

an MDM.sub.-- MakeConnection function for requesting a connection to a remote conferencing node;

an MDM .sub.-- AcceptConnection function for accepting an incoming connection request;

an MDM.sub.-- RejectConnection function for rejecting the incoming connection request;

an MDM.sub.-- Listen function for initiating a listen mode on an established connection;

an MDM.sub.-- CloseConnection function for closing the established connection;

an MDM.sub.-- EndSession function for ending the conferencing session

an MDM.sub.-- GetCharacteristics function for retrieving information about the media dependent module;

an MDM.sub.-- ClearToSend function for verifying that a link packet of a specified size can be sent on the established connection: and

an MDM.sub.-- Send function for sending the link packet on the established connection.

8. The media dependent module of claim 7, wherein:

calling the MDM.sub.-- BeginSession function changes the initialization state to the in-session state:

calling the MDM.sub.-- MakeConnection function changes the in-session state to the connection out state:

receiving a connection accepted message from the remote conferencing node changes the connection out state to the connected state;

receiving a connection request message from the remote conferencing node changes the in-session state to the connection in state;

calling the MDM.sub.-- AcceptConnection function changes the connection in state to the connected state:

calling the MDM.sub.-- RejectConnection function changes the connection in state to the in-session state:

calling the MDM.sub.-- CloseConnection function changes the connected state to the in-session state: and

calling the MDM.sub.-- EndSession function changes the in-session state to the initialization state.

9. The media dependent module of claim 8, wherein calling any of the MDM.sub.-- Listen, MDM.sub.-- GetCharacteristics, MDM.sub.-- ClearToSend, and MDM.sub.-- Send functions leaves the connection state machine unchanged.

10. The media dependent module of claim 7, wherein:

the MDM.sub.-- BeginSession function returns synchronously;

in response to the MDM.sub.-- MakeConnection function, the media dependent module sends one of a connection-established callback and a connection-rejected callback to the conferencing driver and the media dependent module sends a connection-requested callback to the remote conferencing node:

in response to the MDM.sub.-- AcceptConnection function, the media dependent module sends the connection-established callback to the conferencing driver and the media dependent module sends the connection-established callback to the remote conferencing node;

in response to the MDM.sub.-- RejectConnection function, the media dependent module sends the connection-rejected callback to the remote conferencing node;

in response to the MDM.sub.-- Listen function, the media dependent module sends the connection-requested callback to the conferencing driver;

in response to the MDM.sub.-- CloseConnection function, the media dependent module sends a connection-close-complete callback to the conferencing driver and a connection-close-notify callback to the remote conferencing node;

in response to the MDM.sub.-- EndSession function, the media dependent module sends a session-closed callback to the conferencing driver; and

in response to the MDM.sub.-- Send function, the media dependent module sends a send-complete callback to the conferencing driver and the media dependent module sends a data-receive callback to remote conferencing node.

Description Submit all comments and votes

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to audio/video conferencing, and, in particular, to systems for real-time audio, video, and data conferencing in windowed environments on personal computer systems.

2. Description of the Related Art

It is desirable to provide real-time audio, video, and data conferencing between personal computer (PC) systems operating in windowed environments such as those provided by versions of Microsoft.RTM. Windows.TM. operating system. There are difficulties, however, with providing real-time conferencing in non-real-time windowed environments. It is also desirable to provide conferencing between PC systems over two or more different transports.

It is accordingly an object of this invention to overcome the disadvantages and drawbacks of the known art and to provide real-time audio, video, and data conferencing between PC systems operating in non-real-time windowed environments over two or more different transports.

it is a particular object of the present invention to provide real-time audio, video, and data conferencing between PC systems operating under a Microsoft.RTM. Windows.TM. operating system over ISDN and LAN networks.

Further objects and advantages of this invention will become apparent from the detailed description of a preferred embodiment which follows.

SUMMARY OF THE INVENTION

The present invention comprises a media dependent module for a computer-based conferencing system. According to a preferred embodiment, the media dependent module provides an interface between an upper-level conferencing driver of the conferencing system and a lower-level communications driver of the conferencing system to isolate the conferencing driver from the communications driver. The media dependent module is dependent upon hardware of the communications driver, and the media dependent module is adapted to perform a plurality of functions called by the conferencing driver. The plurality of functions comprises a first function for preparing the media dependent module for a conferencing session; a second function for requesting a connection to a remote conferencing node; a third function for accepting an incoming connection request; a fourth function for rejecting the incoming connection request: a fifth function for initiating a listen mode on an established connection; a sixth function for closing the established connection; a seventh function for ending the conferencing session; an eighth function for retrieving information about the media dependent module; a ninth function tier verifying that a link packet of a specified size can be sent on the established connection; and a tenth function for sending the link packet on the established connection.

The present invention also comprises a media dependent module for a computer-based conferencing system. According to a preferred embodiment, the media dependent module provides an interface between an upper-level conferencing driver of the conferencing system and a lower-level communications driver of the conferencing system to isolate the conferencing driver from the communications driver. The media dependent module is dependent upon hardware of the communications driver, and the media dependent module comprises a connection state machine.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, and advantages of the present invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings in which:

FIG. 1 is a block diagram representing real-time point-to-point audio, video, and data conferencing between two PC systems:

FIG. 2 is a block diagram of the hardware configuration of the conferencing system of each PC system of FIG. 1;

FIG. 3 is a block diagram of the hardware configuration of the video board of the conferencing system of FIG. 2;

FIG. 4 is a block diagram of the hardware configuration of the audio/comm (ISDN) board of the conferencing system of FIG. 2;

FIG. 5 is a block diagram of the so,are configuration of the conferencing system of each PC system of FIG. 1;

FIG. 6 is a block diagram of the hardware configuration of the audio/comm (ISDN) board of FIG. 4;

FIG. 7 is a block diagram of the conferencing interface layer between the conferencing applications of FIG. 5, on one side, and the comm, video, and audio managers of FIG. 5, on the other side:

FIG. 8 is a representation of the conferencing call finite state machine (FSM) for a conferencing session between a local conferencing system (i.e., caller) and a remote conferencing system (i.e., callee);

FIG. 9 is a representation of the conferencing stream FSM for each conferencing system participating in a conferencing session;

FIG. 10 is a representation of the video FSM for the local video stream and the remote video stream of a conferencing system during a conferencing session;

FIG. 11 is a block diagram of the software components of the video manager of the conferencing system of FIG. 5;

FIG. 12 is a representation of a sequence of N walking key frames;

FIG. 13 is a representation of the audio FSM for the local audio stream and the remote audio stream of a conferencing system during a conferencing session;

FIG. 14 is a block diagram of the architecture of the audio subsystem of the conferencing system of FIG. 5:

FIG. 15 is a block diagram of the interface between the audio task of FIG. 5 and the audio hardware of audio/comm (ISDN) board of FIG. 2;

FIG. 16 is a block diagram of the interface between the audio task and the comm task of FIG. 5;

FIG. 17 is a block diagram of the comm subsystem of the conferencing system of FIG. 5;

FIG. 18 is a block diagram of the comm subsystem architecture for two conferencing systems of FIG. 5 participating in a conferencing session over an ISDN connection;

FIG. 19 is a representation of the comm subsystem application FSM for a conferencing session between a local site and a remote site;

FIG. 20 is a representation of the comm subsystem connection FSM for a conferencing session between a local site and a remote site;

FIG. 21 is a representation of the comm subsystem control channel handshake FSM for a conferencing session between a local site and a remote site;

FIG. 22 is a representation of the comm subsystem channel establishment FSM for a conferencing session between a local site and a remote site;

FIG. 23 is a representation of the comm subsystem processing for a typical conferencing session between a caller and a callee;

FIG. 24 is a representation of the structure of a video packet as sent to or received from the comm subsystem of the conferencing system of FIG. 5;

FIG. 25 is a representation of the compressed video bitstream for the conferencing system of FIG. 5;

FIG. 26 is a representation of a compressed audio packet for the conferencing system of FIG. 5;

FIG. 27 is a representation of the reliable transport comm packet structure;

FIG. 28 is a representation of the unreliable transport comm packet structure;

FIG. 29 are diagrams indicating typical TII-DLM connection setup and teardown sequences;

FIGS. 30 and 31 are diagrams of the architecture of the audio/comm (ISDN) board;

FIG. 32 is a diagram of the audio/comm (ISDN) board environment;

FIG. 33 is a flow diagram of the on-demand application invocation processing of the conferencing system of FIG. 5;

FIG. 34 is a flow diagram of an example of the processing implemented within the conferencing system of FIG. 5 to manage two conferencing applications in a single conferencing session with a remote conferencing system;

FIG. 35 represents the flow of bits between two remote high-resolution counters used to maintain clock values over a conferencing network;

FIG. 36 is a flow diagram of the processing of the conferencing system of FIG. 1 to control the flow of signals over reliable channels;

FIG. 37 is a flow diagram of the preemptive priority-based transmission processing implemented by the communications subsystem of the conferencing system of FIG. 1;

FIG. 38 is a state diagram for the complete rate negotiation processing;

FIG. 39 is a state diagram for the rate negotiation processing for a called node during a 64 KBPS upgrade;

FIG. 40 is a state diagram for the rate negotiation processing for a calling node during a 64 KBPS upgrade; and

FIG. 41 is a state diagram for the rate negotiation processing in loopback mode during a 64 KBPS upgrade;

FIG. 42 is a flow diagram of the processing by the conferencing system of

FIGS. 5 and 17 during the automatic transport detection implemented at install time;

FIG. 43 is a block diagram showing the network connections made by the conferencing system of FIGS. 5 and 17 during the automatic transport detection implemented at run time;

FIG. 44 is a representation of the DLMLAN packet header format;

FIG. 45 is a representation of the MDM packet header format for LAN transmissions;

FIG. 46 is a representation of the connection messages for a typical conferencing session from the perspective of the MDMs on the local and remote nodes;

FIG. 47 is a flow diagram of the video negotiation processing between two conferencing systems of FIG. 1;

FIG. 48 is a flow diagram of the call-progress processing when the placement of a conference call is successful;

FIG. 49 is a representation of the interrupt-time processing for receiving data signals by the audio/video conferencing system of FIG. 5;

FIG. 50 is a representation of the interrupt-time processing for transmitting data signals by the audio/video conferencing system of FIG. 5;

FIG. 51 is a representation of the auto registration environment for video conferencing;

FIG. 52 is a representation of the architecture for auto registration and remote confidence testing for the new node of FIG. 51;

FIG. 53 is a flow diagram of the processing for the auto registration and remote confidence testing of the auto registration environment of FIG. 51;

FIG. 54 is a flow diagram of the processing implemented by the client (i.e., a new node) for the auto registration processing of FIG. 53;

FIG. 55 is a flow diagram of the processing implemented by a confidence test server for the auto registration processing of FIG. 53;

FIG. 56 is a representation of the auto registration file format; and

FIG. 57 are connection diagrams that show the interactions between a DLM and an MDM in connection and session establishment and tear-down.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Point-To-Point Conferencing Network

Referring now to FIG. 1, there is shown a block diagram representing real-time point-to-point audio, video, and data conferencing between two PC systems, according to a preferred embodiment of the present invention. Each PC system has a conferencing system 100, a camera 102, a microphone 104, a monitor 106, and a speaker 108. The conferencing systems communicate via network 110, which may be either an integrated services digital network (ISDN), a local area network (LAN), or a wide area network (WAN). Each conferencing system 100 receives, digitizes, and compresses the analog video signals generated by camera 102 and the analog audio signals generated by microphone 104. The compressed digital video and audio signals are transmitted to the other conferencing system via network 110, where they are decompressed and converted for play on monitor 106 and speaker 108, respectively. In addition, each conferencing system 100 may generate and transmit data signals to the other conferencing system 100 for play on monitor 106. The video and data signals are displayed in different windows on monitor 106. Each conferencing system 100 may also display the locally generated video signals in a separate window.

Camera 102 may be any suitable camera for generating NSTC or PAL analog video signals. Microphone 104 may be any suitable microphone for generating analog audio signals. Monitor 106 may be any suitable monitor for displaying video and graphics images and is preferably a VGA monitor. Speaker 108 may be any suitable device for playing analog audio signals and is preferably a headset.

Conferencing System Hardware Configuration

Referring now to FIG. 2, there is shown a block diagram of the hardware configuration of each conferencing system 100 of FIG. 1. Each conferencing system 100 comprises host processor 202, video board 204, audio/comm (ISDN) board 206, LAN board 210, and ISA bus 208.

Referring now to FIG. 3, there is shown a block diagram of the hardware configuration of video board 204 of FIG. 2. Video board 204 comprises industry standard architecture (ISA) bus interface 310, video bus 312, pixel processor 302, video random access memory (VRAM) device 304, video capture module 306, and video analog-to-digital (A/D) converter 308.

Referring now to FIG. 4, there is shown a block diagram of the hardware configuration of audio/comm (ISDN) board 206 of FIG. 2. Audio/comm (ISDN) board 206 comprises ISDN interface 402, memory 404, digital signal processor (DSP) 406, and ISA bus interface 408, audio input/output (I/O) hardware 410.

LAN board 210 of FIG. 2 may be any conventional LAN card that supports standard driver interfaces and is preferably an Intel.RTM. EtherExpress.TM. 16C LAN Combo Card.

Conferencing System Software Configuration

Referring now to FIG. 5, there is shown a block diagram of the software configuration each conferencing system 100 of FIG. 1. Video microcode 530 resides and runs on pixel processor 302 of video board 204 of FIG. 3. Comm task 540 and audio task 538 reside and run on DSP 406 of audio/comm (ISDN) board 206 of FIG. 4. The one or more network stacks 560 reside and run partially on host processor 202 of FIG. 2 and partially on LAN board 210 of FIG. 2. All of the other software modules depicted in FIG. 5 reside and run on host processor 202.

Video, Audio, and Data Processing

Referring now to FIGS. 3, 4, and 5, audio/video conferencing application 502 running on host processor 202 provides the top-level local control of audio and video conferencing between a local conferencing system (i.e., local site or endpoint) and a remote conferencing system (i.e., remote site or endpoint). Audio/video conferencing application 502 controls local audio and video processing and establishes links with the remote site f