# US 7,613,615 B1 · Circuits, systems, and methods for real-time de-shuffling of shuffled audio data

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- Number: US 7,613,615 B1
- Document ID: US7613615B1
- Status: Granted
- Kind: B1
- Application number: 10/871,287
- Filed: 2004-06-17
- Granted: 2009-11-03
- Earliest claimed: 2004-06-17
- Assignees: Magnum Semiconductor, Inc.
- Inventors: Akhtar Mahmood; Cheng-Tie Chen; Ting-Chung Chen
- Web page: https://patentgrep.com/patent/US7613615B1

## CPC

- G11B 20/1866: {by interleaving (G11B20/1809 takes precedence)}
- G11B 20/10527: {Audio or video recording; Data buffering arrangements (G11B20/12 - G11B20/18 take precedence)}
- G11B 20/1262: {with more than one format/standard, e.g. conversion from CD-audio format to R-DAT format}
- G11B 2020/00036: {AC-3, i.e. ATSC digital audio compression standard}
- G11B 2020/00057: {MPEG-1 or MPEG-2 audio layer III [MP3]}
- G11B 2020/10759: {content data}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

A data de-shuffler includes a buffer having a set of addressable locations for storing data and control circuitry for de-shuffling a sequence of shuffled data samples. The control circuitry stores a first data sample of the sequence of shuffled data samples at a first location in the buffer with a first address generated from an entry in a look up table and stores a second data sample at a second location in the buffer with a second address generated by incrementing from the first address by a selected incrementation value. The first and second locations in the buffer place the first and second samples in corresponding positions in an un-shuffled sequence of samples.

## Claims

### Claim 1

An audio system comprising:
input circuitry for inputting a stream of audio data shuffled in accordance with a selected shuffling algorithm;
a de-shuffler for de-shuffling the stream of audio samples, the de-shuffler operable to:
store a first audio sample of each data sync block of each track of an audio block in a buffer location corresponding to an address generated from a look-up table; and
store each remaining audio sample of each data sync block of each track of the audio block in a buffer location corresponding to an address generated by incrementing by an incrementation value from a base address provided by the address generated from the look-up table, wherein the incrementation value is selected according to the selected shuffling algorithm;
a memory for storing a sequence of de-shuffled audio samples of an audio block output from the buffer locations, wherein the memory stores two copies of the de-shuffled audio samples output from the buffer locations;
processing circuitry for compressing one of the two copies of the audio samples stored in memory; and
loop-back circuitry for playing-back another one of the two copies of the audio samples stored in memory.

### Claim 2 (depends on 1)

The audio system of claim 1, wherein the buffer locations are disposed in a selected one of set of alternating buffers, the selected one of the buffers storing audio samples being deshuffled by the de-shuffler and a second one of the buffers concurrently providing de-shuffled audio samples to the memory.

### Claim 3 (depends on 1)

The audio system of claim 1, wherein the processing circuitry compresses the one of the two copies of the audio samples into a selected one of MPEG and AC3 compression formats.

### Claim 4 (depends on 1)

The audio system of claim 1, wherein the look-up table is selected from a set of look-up tables for respectively de-shuffling NTSC and PAL format audio samples and the incrementation value is selected from a set of constants for respectively de-shuffling NTSC and PAL format audio samples.

### Claim 5 (depends on 4)

The audio system of claim 4, wherein the audio system is fabricated on a single integrated circuit chip.

### Claim 6 (depends on 1)

The audio system of claim 1, wherein the stream of shuffled data samples comprises a stream of data samples each associated with an audio sync block, a track number, and an audio block in accordance with the digital video (DV) standard.

### Claim 7 (depends on 6)

The audio system of claim 6; wherein each sample comprises two bytes of data encoded in a selected one of the 48 k, 44.1 k, and 32 k modes in accordance with the digital video (DV) standard.

### Claim 8 (depends on 6)

The audio system of claim 6, wherein each sample-pair comprises two twelve-bit samples of data encoded in the 32 k 2ch mode in accordance with the digital video (DV) standard.

### Claim 9 (depends on 6)

The audio system of claim 6, wherein the first sample of the stream of shuffled data comprises a first sample in a corresponding audio sync block and the second sample of the stream of shuffled data comprises another sample in the audio sync block.

### Claim 10 (depends on 6)

The audio system of claim 6, wherein the stream of shuffled data is formatted in accordance with a selected one of NTSC and PAL audio formats in accordance with the digital video (DV) standard.