Kernal-mode audio processing modules

• US 6,974,901 B2
• Filed: 12/17/2004
• Issued: 12/13/2005
• 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): Fletcher, Marlon
• Application Number:
  US11/015,693
• Publication Number:
  US 20050103190A1
• Time in Patent Office: 361 Days
• Field of Search: 84600-606, 84609-610, 84622-625, 846/45, 84649-650, 84659-660, 381/29, 381/34, 704/500, 704/503
• US Class Current: 84/626
• 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 7/002 using a common processing for different operations or calculations, and a set of microinstructions (programme) to control the sequence thereof

Abstract

Multiple kernel-mode audio processing modules or filters are combined to form a module or filter graph. The graph is implemented in kernel-mode, reducing latency and jitter when handling audio data (e.g., MIDI data) by avoiding transfers of the audio data to user-mode applications for processing. A variety of different audio processing modules can be used to provide various pieces of functionality when processing audio data.

Claims

1. A system, for use in kernel-mode, comprising:

means for receiving a data packet including audio data;

means for checking which channel the audio data corresponds to;

means for identifying, based at least in part on the channel, a new channel for the data packet;

means for modifying the audio data to include the new channel;

means for maintaining a channel to new channel mapping, for use in the identifying, in which a single channel can map to multiple new channels; and

means for, if the means for identifying, indicates that the channel corresponds to multiple new channels,

obtaining a new data structure for one of the new channels,

copying the audio data from the data packet into the new data structure, and

setting the channel in the new data structure to be one of the new channels.

2. A system as recited in claim 1, wherein a set of channel to new channel mappings for use by the means for identifying is received by the system via a set parameters interface.

3. A system as recited in claim 1, wherein in the channel to new channel mapping, multiple channels can map to the same new channel.

4. A system as recited in claim 1, wherein the data packet includes:

a structure byte count portion that identifies a size of the data packet;

a channel group portion that identifies which of a plurality of channel groups the audio data corresponds to; and

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

5. A system as recited in claim 1, wherein the channel to new channel mapping comprises a matrix having input channels represented along one axis and output channels represented along another axis, and wherein for each input channel values in the matrix identify which output channels are to be the multiple new channels.

6. A system as recited in claim 1, wherein the means for obtaining, copying, and setting comprises means for obtaining a new data structure for each of the multiple new channels, copying the audio data from the data packet into each of the new data structures, and setting the channel in each of the new data structures to be a different one of the multiple new channels.

7. A method, implemented in a kernel-mode of a computer, the method comprising:

receiving a data packet including audio data;

checking which channel the audio data corresponds to;

identifying, based at least in part on the channel, a new channel for the data packet;

modifying the audio data to include the new channel;

maintaining a channel to new channel mapping, for use in the identifying, in which a single channel can map to multiple new channels; and

if the identifying indicates that the channel corresponds to multiple new channels, then

obtaining a new data structure for one of the new channels,

copying the audio data from the data packet into the new data structure, and

setting the channel in the new data structure to be one of the new channels.

8. A method as recited in claim 7, wherein a set of channel to new channel mappings for use in the identifying is received via a set parameters interface.

9. A method as recited in claim 7, wherein in the channel to new channel mapping, multiple channels can map to the same new channel.

10. A method as recited in claim 7, wherein the data packet includes:

a structure byte count portion that identifies a size of the data packet;

a channel group portion that identifies which of a plurality of channel groups the audio data corresponds to; and

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

11. A method as recited in claim 7, further comprising performing the obtaining, copying, and setting for each of the multiple new channels.

12. A method as recited in claim 7, wherein the channel to new channel mapping comprises a matrix having input channels represented along one axis and output channels represented along another axis, and wherein for each input channel values in the matrix identify which output channels are to be the multiple new channels.

13. A computer comprising:

a processor; and

a memory, coupled to the processor, storing instructions that, when executed by the processor in kernel-mode, cause the processor to;

receive a data packet including audio data;

check a velocity value and a note value that the audio data corresponds to;

identify, based at least in part on both the velocity value and the note value, a new velocity value and a new note value for the data packet;

obtain a new data packet from an allocator module;

copy at least a portion of the audio data from the data packet into the new data packet;

set a note value corresponding to the audio data in the new data packet to equal the new note value; and

set a velocity value corresponding to the audio data in the new data packet to equal the new velocity value.

14. A computer as recited in claim 13, wherein to identify the new velocity value and the new note value is to access a table mapping note and velocity values to new note and new velocity values.

15. A computer as recited in claim 13, wherein the data packet includes:

a structure byte count portion that identifies a size of the data packet;

a channel group portion that identifies which of a plurality of channel groups the audio data corresponds to; and

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

16. A computer as recited in claim 13, wherein the new data packet is a duplicate of the data packet except for the new note value and the new velocity value in the new data packet.