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US 6,330,335 B1Granted
Audio steganography
AssigneeDigimarc Corporation
InventorGeoffrey B. Rhoads
Life of this patent
Estimating the term…
Abstract
An identification code signal is hidden in a carrier signal (such as an electronic data signal or a physical medium) in a manner that permits the identification signal later to be discerned. The carrier signal can thereby be identified, or some machine responsive action can thereby be taken. The technique can be applied in video imagery embodiments to control associated video equipment, e.g. to serve as a copy control signal.
Claims36
A method of processing input audio data to steganographically encode a multi-bit code therein, thereby producing output audio data, characterized by:
- defining a global scaling parameter;
- algorithmically determining, from the input audio data, a first parameter for each of a first plurality of portions of the audio data, said first parameter relating to the relative capability of said portion to conceal encoding thereof;
- encoding at least a portion of the code through each of a second plurality of portions of the audio data to produce the output audio data, said second plurality being a subset of the first plurality, the code in each of said second plurality of portions being encoded in accordance with both the first parameter corresponding to said each portion, and said global scaling parameter;
- wherein the relative strength of the code through different portions of the output audio changes both in accordance with characteristics of the input audio, and globally in accordance with a global scale factor.
1 more element
A method of steganographically embedding multi-bit auxiliary data into an input audio signal that is thereafter compressed to yield a compressed signal, said embedding being both locally adapted based on audio contents and globally adjustable, and thereafter discerning the multi-bit auxiliary data from a non-identical counterpart to said audio signal obtained by decompressing the compressed signal, the method comprising encoding and decoding processes characterized in that:
- (A) the encoding process includes:
- (1) providing an input audio signal comprising a plurality of sample values;
- (2) providing a control by which a user can set the relative value of a global scaling parameter, said parameter determining a relative strength at which the multi-bit auxiliary data will be embedded into the audio signal;
- (3) for each of a plurality of portions of the audio data, algorithmically determining a first parameter corresponding thereto, said first parameter relating to the relative capability of said portion to conceal encoding thereof by the auxiliary data;
- (4) for each of a plurality of samples in said audio, transforming the value thereof in accordance with:
- (a) a first parameter corresponding thereto,
- (b) the global scaling parameter, and
- (c) at least some of said multi-bit auxiliary data, wherein first encoded audio data is produced having the auxiliary data embedded therein, said embedding being both globally scaled, and locally adapted based on audio contents;
- and
- (6) compressing the first encoded audio data;
- and
- (B) the decoding process includes;
- (1) decompressing the compressed first encoded audio data to produce second encoded audio data, said second encoded audio data being non-identical to the first encoded audio data due to said compression/decompression process;
- (2) discerning the multi-bit auxiliary data from the second encoded audio data without reference to the input audio signal.
11 more elements
A method useful for restricting use of audio signals comprising:
- providing an input audio signal;
- providing a multi-bit data signal with which the input audio signal is to be steganographically encoded, said multi-bit data signal including a usage control signal;
- establishing a global scaling parameter for use with said input audio signal, said global parameter determining a relative strength at which the multi-bit data signal will be steganographically encoded therein;
- processing the input audio signal in accordance with said multi-bit data signal and said global scaling parameter, wherein an encoded audio signal is produced having the multi-bit data signal encoded therein, said encoding being manifested as slight changes to sample values in said audio signal when said signal is represented in the sampled time domain;
- compressing the encoded audio signal with a lossy compression process;
- storing the compressed encoded audio signal on a storage medium;
- reading the compressed encoded audio signal from said storage medium using an audio device that includes an audio playback feature;
- decompressing said read compressed encoded audio signal, yielding a corrupted audio signal, said corruption being due to lossiness of the compression/decompression process;
- applying said corrupted audio signal to hardware decoder circuitry within said audio device;
- said hardware decoder circuitry recovering said multi-bit data signal from the corrupted audio signal over the course of a portions thereof, said plurality of portions enhancing a signal-to-noise ratio of said encoded multi-bit data signal, allowing reliable recovery thereof despite steganographic encoding of said multi-bit data signal, and corruption of said audio signal by said compression/decompression lossiness;
- and
- limiting use of said audio device in accordance with the usage control signal included in said multi-bit data signal.
9 more elements
A method useful for restricting use of audio signals comprising:
- providing an input audio signal;
- providing a multi-bit data signal with which the input audio signal is to be steganographically encoded, said multi-bit data signal including a usage control signal;
- establishing a global scaling parameter for use with said input audio signal, said global scaling parameter determining a relative strength at which the multi-bit data signal will be steganographically encoded therein;
- processing the input audio signal in accordance with said multi-bit data signal and said global scaling parameter, wherein an encoded audio signal is produced having the multi-bit data signal encoded therein, said encoding being manifested as slight changes to sample values in said audio signal when said signal is represented in the sampled time domain;
- compressing the encoded audio signal with a lossy compression process;
- storing the compressed encoded audio signal on a storage medium;
- reading the compressed encoded audio signal from said storage medium using an audio device;
- decompressing said read compressed encoded audio signal, yielding a corrupted audio signal, said corruption being due to lossiness of the compression/decompression process;
- applying said corrupted audio signal to a processor within said audio device;
- said processor recovering said multi-bit data signal from the corrupted audio signal notwithstanding corruption of said audio signal by said compression/decompression lossiness;
- and
- limiting use of said audio device in accordance with the usage control signal included in said multi-bit data signal.
9 more elements
Dependencies are inferred from the claim text.