MULTIPOINT PROCESSING UNIT

• US 20080005246A1
• Filed: 08/14/2007
• Published: 01/03/2008
• Est. Priority Date: 03/30/2000
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: VanBuskirk, Michael, Ferriere, Philippe, Han, Mu
• Granted Patent: US 7,698,365 B2
• Time in Patent Office: Days
• US Class Current: 709/204
• CPC Class Codes: H04L 12/1822 Conducting the conference, e.g. admission, detection, selection or grouping of participants, correlating users to one or more conference sessions, prioritising transmission
• CPC Class Codes: H04L 65/103 in the network
• CPC Class Codes: H04L 65/104 in the network
• CPC Class Codes: H04L 65/4038 with floor control
• CPC Class Codes: H04L 65/765 intermediate
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04N 7/152 Multipoint control units therefor

Abstract

A system to provide a multipoint processing terminal and a multicast bridging terminal to provide mixing, switching, and other processing of media streams under the control of H.323 components. Application Programming Interfaces defined for the multipoint processing terminal provide a multipoint control unit with the capability to change the default behavior of the multipoint processing terminal by allowing the multipoint control unit to control the routing audio and video streams in the multipoint processing terminal and control the media formats in a multipoint conference. Multipoint processing acceleration functionality is provided by providing interfaces to allow hardware accelerated implementations of multipoint processing terminals. The multicast bridging terminals enables clients using one type of control signaling and media streaming to join other conferences using different types of control signaling and media streaming by receiving audio or video data from an incoming media stream and performing any processing necessary to transform the media stream from the incoming stream data format to the outgoing stream data format.

Claims

1-20. -20. (canceled)

21. A multipoint processing accelerator apparatus for transmitting audio and video data over a plurality of channels in a multipoint conference being controlled by an application, the application controlling the apparatus by an application program interface of the apparatus, the apparatus comprising:

at least one hardware module having a default operation for applying signal processing operations to at least one of the audio and video data; and

a minidriver, said minidriver communicating with the application through at least one property set to do one of receiving a command to modify the default operation of the at least one hardware module and sending a command to the application.

22. The apparatus according to claim 21 wherein the at least one property set comprises an audio topology property set.

23. The apparatus according to claim 22 wherein the audio topology property set comprises:

a property to do one of updating an audio crossbar content and retrieving an audio crossbar content;

a property to retrieve mixing and transcoding capabilities of an audio crossbar;

a property to do one of setting a periodicity of an interrupt service routine and getting a periodicity of an interrupt service routine;

a property to do one of setting a maximum number of mixed input signals and getting a maximum number of mixed input signals;

a property to do one of enabling silence detection and disabling silence detection;

a property to do one of enabling automatic gain control and disabling automatic gain control; and

a property to retrieve a value of an audio level of a list of audio input streams.

24. The apparatus according to claim 21 wherein the at least one property set comprises a video topology property set.

25. The apparatus according to claim 24 wherein the video topology property set comprises:

a property to do one of updating a video crossbar content and retrieving a video crossbar content;

a property to retrieve picture composition capabilities of the video crossbar;

a property to do one of setting a periodicity of an interrupt service routine and getting a periodicity of an interrupt service routine;

a property to do one of setting a time to evaluate whether a speaker is continuing to speak and getting a time to evaluate whether a speaker is continuing to speak;

a property to do one of setting a second time during which a speaker and a video switching process can not be taken over by a second speaker and getting a second time during which a speaker and a video switching process can not be taken over by a second speaker; and

a property to do one of setting a third time and getting a third time, the third time being the time when a switch is made and when a fast update request is sent to the speaker'"'"'s system.

26. The apparatus according to claim 21 wherein the at least one property set comprises a decoder property set.

27. The apparatus according to claim 26 wherein the decoder property set comprises:

a property to specify that a video frame update be completed and a video frame be displayed until receiving a release signal; and

a property to indicate a video temporal and spatial trade-off of an encoder.

28-41. -41. (canceled)

42. A computer-readable medium having computer-executable instructions for bridging a plurality of multicast conferences, each of the plurality of multicast conferences having at least one client, the computer-executable instructions performing the steps of:

receiving a first call from one of the at least one client to join a conference;

looking for the conference; and

joining the one of the at least one client into the conference, the step of joining comprising;

creating a second call to call the conference;

creating at least one multicast bridging terminal, the multicast bridging terminal bridging a client using one type of control signaling and media streaming to a conference that is using at least one other type of control signaling and media streaming;

selecting one of at least one audio stream and at least one video stream onto the at least one multicast bridging terminal;

connecting the second call; and

answering the first call.

43. The computer-readable medium of claim 42 wherein the at least one multicast bridging terminal comprises one of at least one audio bridge terminal and at least one video bridge terminal.

44. The computer-readable medium of claim 43 wherein the at least one multicast bridging terminal comprises:

a sink module to receive at least one input stream from one of the first call and one of the second call;

a source module to send at least one output stream to one of the first call and one of the second call; and

an interface to send one of at least one input stream to the source module.

45. The computer-readable medium of claim 44 wherein a data format of the at least one iriput stream and a data format of the at least one output stream is identical

46. The computer-readable medium of claim 45 wherein the at least one input stream is an audio stream and the at least one output stream is an audio stream, the data format being PCM linear at 16 bits per sample at 8 KHz.

47. The computer-readable medium of claim 45 wherein the at least one input stream is a video stream and the at least one output stream is a videostream, the data format being RTP H.263.

48. The computer-readable medium of claim 44 wherein the sink filter uses a memory allocator in an output pin of an upstream module, the upstream module sending the at least one input stream to the sink filter.

49. The computer-readable medium of claim 44 wherein the sink module is an audio sink module and the at least one input stream is at least one, input audio stream, the computer-executable instructions further comprising the step of timestamping, by the audio sink module, audio samples in the at least one audio input stream with a time of a clock of the audio sink module.

50. The computer-readable medium of claim 49 further comprising the step of updating the clock when a discontinuity flag is set.

51. The computer-readable medium of claim 50 wherein the discontinuity flag is set when a first sample of a talk spurt is delivered to the audio sink filter.

52. The computer-readable medium of claim 50 further comprising the steps of:

if the data in the at least one input stream is continuous data, increasing the clock by a first time, the first time based on an amount of data passed through the audio sink module; and

if there is a silence period in the at least one audio input stream, adjusting the clock by a second time, the second time being the length of time of the silence period.

53. The computer-readable medium of claim 45 wherein the data in the input stream is in frames of a first size and the data in the output stream is in frames of a second size, the computer-executable instructions further comprising the steps of:

calling, by the sink module, the interface to send data samples of the first size to the source filter;

if the first size is equal to the second size, sending the data in the input stream directly down stream; and

if the first size is not equal to the second size, constructing, by the source module, new data frames of the second size, transforming the data samples of the first size into data samples of the second size, copying the data samples of the second size into the new data frames, and sending the new data frames down stream.

54. The computer-readable medium of claim 53 wherein the sink module is a video sink module, the at least one input stream is at least one input video stream, the video data in the at least one input video stream is in video frames, the video frames containing at least one RTP packets, the computer-executable instructions further comprising the steps of:

monitoring the RTP packets for a parameter change; and

if the parameter changes;

discarding packets, by the video sink module, until an event occurs; and

resume sending video data down stream.