Extensible kernel-mode audio processing architecture

• US 20050283262A1
• Filed: 08/19/2005
• Published: 12/22/2005
• Est. Priority Date: 04/12/2000
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Puryear, Martin G.
• Granted Patent: US 7,673,306 B2
• Time in Patent Office: Days
• US Class Current: 700/94
• CPC Class Codes: G10H 1/0066 using a MIDI interface
• CPC Class Codes: G10H 1/183 Channel-assigning means for polyphonic instruments
• CPC Class Codes: G10H 2210/225 Portamento, i.e. smooth continuously variable pitch-bend, without emphasis of each chromatic pitch during the pitch change, which only stops at the end of the pitch shift, as obtained, e.g. by a MIDI pitch wheel or trombone pitch bend with emphasis of each chromatic pitch during pitch change, e.g. glissando, G10H2210/221
• CPC Class Codes: G10H 2210/281 Reverberation or echo
• CPC Class Codes: G10H 2240/291 SCSI, i.e. Small Computer System Interface
• CPC Class Codes: G10H 2240/295 Packet switched network, e.g. token ring circuit-switched networks, e.g. traditional analog telephone transmission G10H2240/241
• CPC Class Codes: G10H 2240/305 Internet or TCP/IP protocol use for any electrophonic musical instrument data or musical parameter transmission purposes
• CPC Class Codes: G10H 7/00 Instruments in which the tones are synthesised from a data store, e.g. computer organs
• CPC Class Codes: G10H 7/002 using a common processing for different operations or calculations, and a set of microinstructions (programme) to control the sequence thereof

Abstract

An extensible kernel-mode audio (e.g., MIDI) processing architecture is implemented using multiple modules that together comprise a module graph. The module graph is implemented in kernel-mode, reducing latency and jitter when handling audio data by avoiding transfers of the audio data to user-mode applications for processing. In one embodiment, the audio processing architecture is readily extensible. A graph builder can readily change the module graph, adding new modules, removing modules, or altering connections as necessary, all while the graph is running.

Claims

1. A computer-readable medium having stored thereon a data structure, the data structure comprising:

a presentation time portion indicating when audio data is to be rendered;

a data portion that can include audio data or a pointer to a chain of additional data structures that include the audio data; and

a flag portion indicating to a kernel-mode transform filter whether the data portion includes the pointer to the chain of additional data structures.

2. A computer-readable medium as recited in claim 1, wherein the data structure further comprises a structure byte count portion that identifies the size of the data structure.

3. A computer-readable medium as recited in claim 1, wherein the data structure further comprises an event byte count portion that identifies a number of data bytes that are referred to in the data portion.

4. A computer-readable medium as recited in claim 1, wherein the data structure further comprises a channel group portion that identifies which of a plurality of channel groups the data identified in the data portion corresponds to.

5. A computer-readable medium as recited in claim 1, wherein the data structure further comprises a byte position portion including an identifier of where the data structure is situated among a plurality of data structures received from an application.

6. A computer-readable medium as recited in claim 1, wherein the data structure further comprises a next event portion including an identifier of a next data structure in a chain of data structures.

7. A computer-readable medium as recited in claim 1, wherein:

the data portion can further include a pointer to a data buffer; and

the flag portion indicates whether the data portion includes either the pointer to the chain of additional data structures or one of either the audio data or the pointer to the data buffer.

8. A computer-readable medium as recited in claim 7, further comprising an event byte count portion that identifies, if the data portion does not include the pointer to the chain of additional data structures, whether the data portion includes the audio data or a pointer to the data buffer.

9. A method of processing audio data in a privileged level module, the method comprising:

receiving a data packet including a pointer to a chain of additional data packets that include audio data.

10. A method as recited in claim 9, wherein the processing further comprises carrying out a programmed operation on each of the additional data packets.

11. A method as recited in claim 9, further comprising detecting that the data packet includes the pointer based on a package event flag included in the data packet.

12. A computer-readable memory containing a computer program that is executable by a computer to perform the method recited in claim 9.

13. A method of processing audio data in a kernel-mode transform filter, the method comprising:

passing, to another kernel-mode transform filter, a data packet including a pointer to a chain of additional packets that include audio data.

14. A method as recited in claim 13, further comprising indicating that the data packet includes the pointer by setting a package event flag included in the data packet.

15. A computer-readable memory containing a computer program that is executable by a computer to perform the method recited in claim 13.