Digital audio processing

• US 7,672,743 B2
• Filed: 04/25/2005
• Issued: 03/02/2010
• Est. Priority Date: 04/25/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Onders, Timothy, Messer, Christopher, Chen, Wei-ge, Thumpudi, Naveen, Smirnov, Serge, Cheng, Raymond
• Primary Examiner(s): Kuntz; Curtis
• Assistant Examiner(s): Sellers; Daniel R
• Application Number:
  US11/114,873
• Publication Number:
  US 20060241796A1
• Time in Patent Office: 1,772 Days
• Field of Search: 700/94, 370470-474, 704/500
• US Class Current: 700/94
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/4341 Demultiplexing of audio and video streams
• CPC Class Codes: H04N 21/439 Processing of audio elementary streams

Abstract

A compressed digital audio signal is transmitted from an audio source along a connection wire to an audio receiver. The digital audio signal can encode digital audio data having different sampling frequencies, frames sizes, and other information. The audio receiver that receives the digital audio signal can decode and convert the compressed digital audio signal into multiple synchronized analog signals, which are used to drive multiple speakers. The audio receiver may also synchronize the audio data with associated video data so that the audio playback and video playback are “in sync”, despite delay introduced by the audio signal decoding at the audio receiver.

Claims

1. A method for generating a digital audio signal from one or more digital audio samples, the method comprising:

receiving a digital audio frame containing a number of the digital audio samples at a computing device comprising a processing unit;

determining the number of digital audio samples in the digital audio frame; and

generating the digital audio signal as one or more digital audio bursts containing the digital audio frame, at least one of the digital audio bursts comprising a burst payload and a preamble element specifying a data type and a data subtype, wherein;

the data subtype specified by the preamble element indicates the number of digital audio samples in the digital audio frame,

the preamble element supports a plurality of data subtypes and a plurality of sampling frequencies,

the plurality of data subtypes includes at least one data subtype that supports spanning a digital audio frame sampled at a given sampling frequency across multiple digital audio bursts and at least one other data subtype that supports incorporating the digital audio frame sampled at the given sampling frequency into one digital audio burst, and

the data subtype that supports spanning the digital audio frame indicates the number of digital audio samples distributed by the multiple digital audio bursts.

2. The method of claim 1 wherein the digital audio samples were sampled at a sampling frequency and further comprising:

determining the sampling frequency relating to the digital audio samples; and

supplementing at least one of the digital audio bursts to indicate the sampling frequency.

3. The method of claim 1 further comprising:

supplementing the one or more digital audio bursts to include metadata relating to the digital audio samples.

4. The method of claim 1 wherein the digital audio frame is one of a sequence of digital audio frames synchronized with a sequence of video frames and further comprising:

advancing the sequence of digital audio frames by a latency period relative to the sequence of video frames, wherein the latency period represents an amount of time associated with decoding the one or more digital audio bursts for a digital audio frame.

5. The method of claim 4 wherein the latency period is dependent on the number of digital audio samples in the digital audio frame.

6. The method of claim 1 wherein the generating operation distributes the digital audio frame across two of the one or more digital audio bursts.

7. A computer-readable storage medium having computer-executable instructions performing a computer process comprising the method of claim 1.

8. A computer-implemented system for generating a digital audio signal from one or more digital audio samples, the system comprising a processing unit executing computer-executable program modules stored in memory comprising:

a framing module that receives a digital audio frame containing a number of the digital audio samples and determines the number of digital audio samples in the digital audio frame; and

a translation module that generates one or more digital audio bursts containing the digital audio frame, at least one of the digital audio bursts comprising a burst payload and a preamble element specifying a data type and a data subtype, wherein;

the data subtype specified by the preamble element indicates the number of digital audio samples in the digital audio frame,

the preamble element supports a plurality of data subtypes and a plurality of sampling frequencies,

the plurality of data subtypes includes at least one data subtype that supports spanning a digital audio frame sampled at a given sampling frequency across multiple digital audio bursts and at least one other data subtype that supports incorporating the digital audio frame sampled at the given sampling frequency into one digital audio burst, and

the data subtype that supports spanning the digital audio frame indicates the number of digital audio samples distributed by the multiple digital audio bursts.

9. The system of claim 8 wherein the digital audio samples were sampled at a sampling frequency and the translation module further supplements at least one of the digital audio bursts to indicate the sampling frequency.

10. The system of claim 8 wherein the translation module further supplements the one or more digital audio bursts to include metadata relating to the audio samples.

11. The system of claim 8 wherein the digital audio frame is one of a sequence of digital audio frames synchronized with a sequence of video frames and the computer process further comprises:

an audio transmitter that advances the sequence of digital audio frames by a latency period relative to the sequence of video frames, wherein the latency period represents an amount of time associated with decoding of one or more digital audio bursts for a digital audio frame.

12. The system of claim 11 wherein the latency period is dependent on the number of digital audio samples in the digital audio frame.

13. The system of claim 8 wherein the translation modules distributes the digital audio frame across two of the one or more digital audio bursts.

14. A method for decoding a digital audio signal, the method comprising:

receiving one or more digital audio bursts containing a digital audio frame at a computing device comprising a processing unit, at least one of the digital audio bursts comprising a burst payload and a preamble element specifying a data type and a data subtype, wherein;

the data subtype specified by the preamble element indicates the number of digital audio samples in the digital audio frame,

the preamble element supports a plurality of data subtypes and a plurality of sampling frequencies,

the plurality of data subtypes includes at least one data subtype that supports spanning a digital audio frame sampled at a given sampling frequency across multiple digital audio bursts and at least one other data subtype that supports incorporating the digital audio frame sampled at the given sampling frequency into one digital audio burst, and

the data subtype that supports spanning the digital audio frame indicates the number of digital audio samples distributed by the multiple digital audio bursts;

determining a number of digital audio samples contained within the digital audio frame; and

decoding the digital audio frame to generate the digital audio samples based on the number of digital audio samples contained within the digital audio frame.

15. The method of claim 14 wherein the digital audio samples were sampled at a sampling frequency and further comprising:

determining the sampling frequency relating to the digital audio samples from the one or more digital audio bursts; and

converting the digital audio data samples into one or more analog audio signals based on the sampling frequency.

16. The method of claim 14 further comprising:

extracting metadata relating to the digital audio data samples from the one or more digital audio bursts.

17. The method of claim 14 further comprising:

receiving two or more digital audio bursts containing the digital audio frame; and

extracting the digital audio frame from the two or more digital audio bursts.

18. A computer-readable storage medium having computer-executable instructions performing a computer process comprising the method of claim 14.

19. A system for decoding a digital audio signal, the system comprising:

a processor;

a computer-readable storage medium embodying computer-executable instructions performing the method of claim 14, wherein the processor executes the computer-readable instructions.

20. A system for decoding a digital audio signal, the system comprising hardware modules performing the method of claim 14.