Pulse code modulation (PCM) data-marking
AssigneeCirrus Logic, Inc.
InventorsShafagh Kamkar, Bruce E. Duewer, Dylan A. Hester
Life of this patent
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Abstract
An encoding for data in an audio data stream may be indicated in the data stream using a footer stored in low-order bits of data frames in the audio data stream. When the audio data stream may include either Pulse Code Modulation (PCM) or Direct Stream Digital (DSD) data, PCM data may be marked with a footer to indicate the encoding as PCM. The footer may be a fixed value, an alternating fixed value, a predetermined sequence of values, or a value computed based on the PCM data. Examples of computed values for the footer marker may include an error code, an error correction code (ECC), and a scrambled code.
Claims20
A method, comprising:
- receiving an audio data stream;
- analyzing a selected set of low-order bits of a plurality of frames from the audio data stream to determine whether a footer is present indicating the audio data stream is a first format;
- decoding the received audio data stream according to the first format when the footer is present, wherein the decoding comprises decoding high-order bits of a frame of the plurality of frames that also comprises the footer based on the presence of the footer in the frame;
- and
- decoding the received audio data stream according to a second format when the footer is not present.
An apparatus, comprising:
- an audio controller configured to perform steps comprising:
- receiving an audio data stream;
- analyzing a selected set of low-order bits of a plurality of frames from the audio data stream to determine whether a footer is present indicating the audio data stream is a first format;
- decoding the received audio data stream according to the first format when the footer is present, wherein the decoding comprises decoding high-order bits of a frame of the plurality of frames that also comprises the footer based on the presence of the footer in the frame;
- and
- decoding the received audio data stream according to a second format when the footer is not present.
Dependencies are inferred from the claim text.