Extensible kernel-mode audio processing architecture

• US 7,673,306 B2
• Filed: 08/19/2005
• Issued: 03/02/2010
• Est. Priority Date: 04/12/2000
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Puryear, Martin G.
• Primary Examiner(s): Ho; Andy
• Application Number:
  US11/207,632
• Publication Number:
  US 20050283262A1
• Time in Patent Office: 1,656 Days
• Field of Search: 719/312, 709/231, 709/238
• US Class Current: 719/312
• 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
• 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
• 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, a pointer to a data buffer, or a pointer to a chain of additional data structures that include the audio data;

an event byte count portion that identifies whether the data portion includes the audio data or the pointer to the data buffer; and

a flag portion that is set to indicate to a kernel-mode transform filter that the data portion includes the pointer to the chain of additional data structures rather than the audio data or the pointer to the data buffer.

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 event byte count portion 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 method of processing audio data in a privileged level module, the method comprising:

receiving a data packet, the data packet including;

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

a data portion that can include audio data, a pointer to a data buffer, or a pointer to a chain of additional data packets that include the audio data;

an event byte count portion that identifies whether the data portion includes the audio data or the pointer to the data buffer; and

a flag portion that is set to indicated to a kernel-mode transform filter that the data portion includes the pointer to the chain of additional data packets rather than the audio data or the pointer to the data buffer; and

determining that the data portion includes a pointer to a chain of additional data packets based on the flag portion; and

carrying out a programmed operation on each of the additional data packets.

8. A computer-readable memory containing a computer program that is executable by a computer to perform the method recited in claim 7.

9. 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, the data packet including;

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

a data portion that can include audio data, a pointer to a data buffer, or a pointer to a chain of additional data packets that include the audio data;

an event byte count portion that identifies whether the data portion includes the audio data or the pointer to the data buffer; and

a flag portion that is set to indicate to a kernel-mode transform filter that the data portion includes the pointer to the chain of additional data packets rather than the audio data or the pointer to the data buffer; and

configuring the data portion to include a pointer to a chain of additional data packets that include audio data; and

indicating that the data packet includes the pointer by setting a package event flag in the flag portion.

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