Apparatus and method for interpretation and translation of serial digital audio transmission formats

• US 6,212,199 B1
• Filed: 03/18/1997
• Issued: 04/03/2001
• Est. Priority Date: 03/18/1997
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Oxford, William V.
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): SLAVITT, MITCHELL R
• Application Number:
  US08/819,958
• Time in Patent Office: 1,477 Days
• Field of Search: 370/465, 370/466, 370/467, 370/522, 370/472, 370/487, 370/490, 395/200.2, 395/200.21, 395/200.17
• US Class Current: 370/466
• CPC Class Codes: G06F 3/16 Sound input; Sound output speech processing G10L
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00768 wherein copy control information is used, e.g. for indicating whether a content may be copied freely, no more, once, or never, by setting CGMS, SCMS, or CCI flags
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 20/1262 with more than one format/standard, e.g. conversion from CD-audio format to R-DAT format

Abstract

A method and apparatus for processing digital audio data comprises remapping channel status information in an input digital audio bit stream into a uniform format. The channel status information in the uniform format contains a super-set of data included in the channel status block of the original data and comprises a “higher level” form of presentation than the original status information, thereby reducing the amount of processing required by the application program in interpreting the audio data. The translation of audio data between different formats is performed in an interface unit. The interface unit strips the channel status information from the incoming digital audio data, translates the channel status information into a desired form, and then presents the audio data and the translated channel status information to a host computer for further processing or storage. The translation and routing functions performed by the interface unit are controlled by data stored in one or more registers. The contents of the register(s), in turn, can be set and/or interrogated by transmitting commands to the registers over a serial audio interface line.

Claims

1. An interface circuit for receiving serial audio digital data and reformatting the audio digital data to a uniform format, comprising:

an input circuit for receiving input audio digital data from at least one input line, identifying channel status information in the received audio digital data and separating the channel status information from the input audio digital data;

a control circuit for modifying the separated channel status information to generate modified channel status information conforming to said uniform format; and

an output circuit for transmitting said modified channel status information to an external device.

2. The interface circuit of claim 1, further including:

an audio routing matrix for channeling a portion of said input digital audio data from said input circuit to said output circuit.

3. The interface circuit of claim 2, wherein said channeling performed by said audio routing matrix is governed by control information stored within said control circuit.

4. The interface circuit of claim 1, wherein said control circuit includes at least one register including memory cells for defining the manner in which said interface circuit operates.

5. The interface circuit of claim 4, wherein the contents of said at least one register can be interrogated by transmitting an interrogation message to said at least one register.

6. The interface circuit of claim 4, wherein the contents of said at least one register can be set by transmitting a write command to said at least one register.

7. The interface circuit of claim 1, wherein said output circuit assembles the modified channel status information with an audio portion of said audio digital data.

8. A method for receiving serial audio digital data and reformatting the audio digital data to a uniform format, comprising:

receiving input audio digital data from at least one input line;

identifying channel status information within said input audio digital data;

separating said channel status information from said input audio digital data;

modifying the separated channel status information to generate modified channel status information conforming to said uniform format; and

transmitting said modified channel status information to an external device.

9. The method of claim 8, further including the step of:

channeling a portion of said input digital audio data from said input circuit to said output circuit.

10. The method of claim 9, wherein said channeling is governed by control information stored in a control circuit having at least one register.

11. The method of claim 8, wherein said identifying and modifying step is controlled by information stored in a control circuit having at least one register.

12. The method of claim 11, further including a step of interrogating the contents of said at least one register by transmitting an interrogating command to said at least one register.

13. The method of claim 8, further comprising:

assembling the modified channel status information with an audio portion of said audio digital data.

14. The method of claim 11, further including a step of setting the contents of said at least one register by transmitting a write command to said at least one register.

15. An electronic system for processing serial audio digital data, comprising:

an input device for receiving serial audio digital data in a data link layer format;

a translator for remapping said received serial audio data into a uniform level format that comprises a superset of said serial audio digital data; and

an output device for outputting said serial audio data which has been converted to said higher level layer format.

16. An interface circuit for outputting a stream of digital audio data, comprising:

an input circuit for receiving input audio digital data from at least one input line;

a control circuit providing at least one control register containing status information therein, wherein the contents of said control register can be interrogated by transmitting an interrogation message to said register; and

an output circuit for receiving said input audio digital data and said status information from said control register, for combining said input audio digital data with said status information to produce output data, and for transmitting said output data to an external device.

17. An interface circuit for outputting a stream of digital audio data, comprising:

an input circuit for receiving input audio digital data from at least one input line;

a control circuit providing at least one control register containing status information therein, wherein the contents of said control register can be set by transmitting a write command to said register; and

an output circuit for receiving said input audio digital data and said status information from said control register, for combining said input audio digital data with said status information to produce output data, and for transmitting said output data to an external device.

18. An interface circuit for outputting a stream of digital audio data, comprising:

an input circuit for receiving input audio digital data from at least one input line;

a control circuit for providing at least one control register containing status information therein, wherein said control register contains control fields, and wherein a same set and organization of control fields supplies status information for plural output format protocols; and

an output circuit for receiving said input audio digital data and said status information from said control register, for combining said input audio digital data with said status information to produce output data, and for transmitting said output data to an external device.

19. A method for outputting a stream of digital audio data, comprising the steps of:

receiving input audio digital data from at least one input line;

accessing at least one control register containing status information therein;

interrogating the contents of said control register by transmitting an interrogating command to said register;

receiving said input audio digital data and said status information from said control register;

combining said input audio digital data with said status information to produce output data, and

transmitting said output data to an external device.

20. A method for outputting a stream of digital audio data, comprising the steps of:

receiving input audio digital data from at least one input line;

accessing at least one control register containing status information therein;

setting the contents of said register by transmitting a write command to said control register;

receiving said input audio digital data and said status information from said control register;

combining said input audio digital data with said status information to produce output data; and

transmitting said output data to an external device.

21. A method for outputting a stream of digital audio data, comprising the steps of:

receiving input audio digital data from at least one input line;

accessing at least one control register containing status information therein, wherein said control register contains control fields, and wherein a same set and organization of control fields supplies status information for plural output format protocols;

receiving said input audio digital data and said status information from said control register;

combining said input audio digital data with said status information to produce output data; and

transmitting said output data to an external device.