Increased speed of processing of data received over a communications link

• US 8,335,874 B2
• Filed: 10/03/2011
• Issued: 12/18/2012
• Est. Priority Date: 04/14/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Mora, Matthew Xavier, Warren, Niel D.
• Primary Examiner(s): Tsai, Henry
• Assistant Examiner(s): Sun, Michael
• Application Number:
  US13/252,106
• Publication Number:
  US 20120023274A1
• Time in Patent Office: 442 Days
• Field of Search: None
• US Class Current: 710/52
• CPC Class Codes: G06F 3/162 Interface to dedicated audio devices, e.g. audio drivers, interface to CODECs
• CPC Class Codes: G06F 5/065 Partitioned buffers, e.g. allowing multiple independent queues, bidirectional FIFO's
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers
• CPC Class Codes: H04L 49/9063 Intermediate storage in different physical parts of a node or terminal

Abstract

A method and apparatus for processing data samples utilizes a channel map populated by device descriptor, or by an application program interface. Packet processing code loops through all of the samples contained in a packet while incrementing through a channel map and steering table without having to look up a table to determine in what audio buffer the sample is to be stored or read. Additionally, the present invention utilizes a stride map, so the audio subsystem knows how many samples to skip in order to reach the next sample frame. The present invention can be used for handling received packets as well as forming packets to send over a bus.

Claims

1. at least one input channel map;

at least one output channel map; and

a computer readable apparatus comprising non-transitory storage media comprising a computer program having a plurality of instructions which, when executed on said processor, enable said apparatus to;

unpack a plurality of packets into a first set of said data channels based at least in part on said at least one input channel map;

pack a subset of the first set of said data channels into a second set of data channels based at least in part on said at least one output channel map;

publish the second set of data channels to at least one media device driver; and

where the at least one media device driver is configured to process only the published second set of data channels.

2. The apparatus of claim 1, wherein the published second set of data channels substantially offloads processing from said media device driver.

3. The apparatus of claim 1, wherein each of said data channels comprises a plurality of sequential data samples.

4. The apparatus of claim 1, further comprising instructions which, when executed on the processor publish a third set of data channels to at least one other media device driver.

5. receiving a device descriptor comprising information enabling unpacking of said at least one frame of data;

publishing, based at least in part on said information enabling unpacking of said frames of data;

a steering table indicating a channel order, said channel order describing an order of packed data channels within said frames of data;

a stride map indicating at least one stride size, said at least one stride size determining a number of data samples to skip, corresponding to others of said data channels, between sequential data samples of the same data channel; and

a channel map indicating one or more start addresses, wherein said start addresses for said data channels reside within a sample buffer, wherein the channel map accommodates a mismatched sample size or packet size with respect to an application stream size.

6. The method of claim 5, wherein the act of publishing the steering table, the stride map, and the channel map substantially offloads processing from said audio device driver.

7. The method of claim 5, further comprising unpacking said at least one frame into its constituent data channels based at least in part on said information received in said device descriptor.

8. The method of claim 5, wherein the mismatched sample size or packet size is larger than the application stream size.

9. The method of claim 8, wherein a driver need only process the application stream size.

10. a computer readable apparatus comprising non-transitory media containing at least one computer program having a plurality of instructions, said plurality of instructions which, when executed, cause said apparatus to:

read a device descriptor, where the device descriptor is configured to enable unpacking of said frames of data;

read one or more of said frames of data in said sample buffer;

unpack said read one or more frames into its constituent data channels based at least in part on said information in said device descriptor; and

publish only a subset of the constituent data channels to an audio device driver, wherein the audio device driver responsively processes only the published subset.

11. The apparatus of claim 10, wherein the subset of the constituent data channels is further stored in an output channel map.

12. The apparatus of claim 11, wherein the audio device driver directly plays the output channel map.

13. The apparatus of claim 10, wherein the published subset of constituent data channels is provided to at least one other audio device driver.

14. The apparatus of claim 13, wherein each data channel comprises one or more Common Isochronous Packets (CIP).

15. a computer readable apparatus comprising non-transitory media containing at least one computer program having a plurality of instructions, said plurality of instructions which, when executed, cause said apparatus to:

receive a device descriptor comprising information enabling unpacking of said frames of data;

read one or more of said frames of data in said sample buffer;

unpack said read one or more frames into a first set of data channels based at least in part on said information in said device descriptor;

pack a second set of data channels from the first set of data channels based at least in part on said information in said device descriptor;

publish the second set of data channels to at least one audio device driver; and

where the at least one audio device driver processes only the published second set of data channels.

16. The apparatus of claim 15, wherein said first interface comprises a IEEE Standard 1394 compliant bus.

17. The apparatus of claim 15, wherein said first interface comprises a Universal Serial Bus (USB) compliant bus.

18. The apparatus of claim 15, further comprising a second interface configured to transmit the second set of data channels to at least one second device.

19. The apparatus of claim 18, wherein the at least one audio device driver is resident within the at least one other second device.

20. The apparatus of claim 18, wherein the at least one audio device driver is local to the apparatus.