Spectral audio encoding
First Claim
1. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
- selecting first and second frequencies from a frequency spectrum associated with the first block of information;
modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies;
selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; and
modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein modulating the characteristic of the audio signal includes increasing the spectral power at one of the first and second frequencies to render the spectral power at the one of the first and second frequencies a local maximum and decreasing the spectral power at the other of the first and second frequencies to render the spectral power at the other of the first and second frequencies a local minimum, and wherein modulating the audio signal includes increasing the spectral power at one of the third and fourth frequencies to render the spectral power at the one of the third and fourth frequencies a local maximum and decreasing the spectral power at the other of the third and fourth frequencies to render the spectral power at the other of the third and fourth frequencies a local minimum.
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Accused Products
Abstract
Blocks of audio are encoded based upon corresponding first and second frequencies. The first and second frequencies are hopped from block to block. An audio quality measure (AQM) is computed for each block of audio such that, if x out of y blocks of audio have an AQM greater than a first predetermined threshold, encoding is suspended. For example, x may be nine and y may be 16. Also, if a ratio of the energy in a front part of a block of audio to the energy in a rear part of the block of audio is greater than a second predetermined threshold, that block of audio is not encoded even though x out of y blocks of audio have an AQM greater than the first predetermined threshold. Multiple distributors of the audio may encode the audio with their corresponding identities using the above processes.
214 Citations
43 Claims
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1. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; and modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein modulating the characteristic of the audio signal includes increasing the spectral power at one of the first and second frequencies to render the spectral power at the one of the first and second frequencies a local maximum and decreasing the spectral power at the other of the first and second frequencies to render the spectral power at the other of the first and second frequencies a local minimum, and wherein modulating the audio signal includes increasing the spectral power at one of the third and fourth frequencies to render the spectral power at the one of the third and fourth frequencies a local maximum and decreasing the spectral power at the other of the third and fourth frequencies to render the spectral power at the other of the third and fourth frequencies a local minimum.
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2. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; and modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein modulating the characteristic of the audio signal includes selectively changing a phase relationship between the first and second frequencies, and wherein modulating the characteristic of the audio signal includes selectively changing a phase relationship between the third and fourth frequencies.
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3. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; and modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein modulating the characteristic of the audio signal includes swapping a spectral amplitude of at least one of the first and second frequencies with a spectral amplitude of a frequency having a maximum amplitude in a frequency neighborhood of the at least one of the first and second frequencies, and wherein modulating the characteristic of the audio signal includes swapping a spectral amplitude of at least one of the third and fourth frequencies with a spectral amplitude of a frequency having a maximum amplitude in a frequency neighborhood of the at least one of the third and fourth frequencies.
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4. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; and modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein the first and second frequencies are offset from the third and fourth frequencies based on a change in a low frequency maximum.
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5. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; and modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein the first and second frequencies are selected according to a reference frequency, a first low frequency maximum and a shift index. - View Dependent Claims (6)
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7. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; and modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein a synchronization block characterized by a triple tone portion is added to the audio signal.
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8. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies; determining an audio quality measure for the first block of information;
comparing the audio quality measure to a reference value; andinhibiting modulating the characteristic of the audio signal in response to the comparison of the audio quality measure and the reference value, wherein the audio quality measure is determined based on a first spectral energy associated with a block of information without coding, a second spectral energy associated with the block of information with coding, and a third spectral energy associated with a masking energy for the block of information.
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9. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies; determining an audio quality measure for each of a plurality of blocks of information associated with the audio signal; comparing the audio quality measure corresponding to each of the plurality of blocks of information to a reference value; and inhibiting modulating the characteristic of the audio signal if a predetermined portion of the plurality of blocks of information have an audio quality measure that exceeds the reference value, wherein inhibiting modulating the characteristic of the audio signal to prevent encoding of at least one of the plurality of blocks of information that has an audio quality measure exceeding a second predetermined reference value.
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10. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies; determining an audio quality measure for each of a plurality of blocks of information associated with the audio signal; comparing the audio quality measure corresponding to each of the plurality of blocks of information to a reference value; and inhibiting modulating the characteristic of the audio signal if a predetermined portion of the plurality of blocks of information have an audio quality measure that exceeds the reference value, wherein the audio quality measure is determined based on a first spectral energy associated with a block of information without coding, a second spectral energy associated with the block of information with coding, and a third spectral energy associated with a masking energy for the block of information.
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11. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; and modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein modulating the characteristic of the audio signal is inhibited based on a comparison of a first energy associated with a first portion of the first block of information and a second energy associated with a second portion of the first block of information. - View Dependent Claims (12, 13, 14)
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15. A method for encoding first and second blocks of information associated with at least a portion of an audio signal with corresponding first and second code portions, comprising:
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selecting first and second frequencies from a frequency spectrum associated with the first block of information; modulating a characteristic of the audio signal to form a first encoded block of information containing first information associated with the audio signal and information associated with the first code portion at each of the first and second frequencies, without substantially eliminating a portion of the audio signal at one of the first and second frequencies; selecting third and fourth frequencies from a frequency spectrum associated with the second block of information, wherein the third and fourth frequencies are offset from the first and second frequencies; modulating the characteristic of the audio signal to form a second encoded block of information containing second information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies; encoding, by use of a primary encoder, a group of blocks of information associated with the audio signal with a synchronization sequence, wherein the primary encoder leaves a predetermined number of groups of additional blocks of information associated with the audio signal unencoded; encoding, by use of either the primary encoder or a secondary encoder, a first corresponding one of the groups of additional blocks of information associated with the audio signal to identify a first distributor of the audio signal; and encoding, by use of a secondary encoder, a second corresponding one of the groups of additional blocks of information associated with the audio signal to identify a second distributor of the audio.
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16. A method of encoding blocks of audio information, comprising:
encoding each of the blocks of audio information by modulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to indicate first and second levels of distribution without substantially eliminating a portion of the audio at one of the first and second frequencies, wherein at least some of the blocks of audio information are encoded to contain distribution level information and audio signal information at each of the selected first and second frequencies, wherein the selected first and second frequencies change from a first one of the blocks of audio information to a second one of the blocks of audio information, wherein encoding each of the blocks of audio information includes encoding a plurality of the blocks of audio information with binary code bits such that some of the binary code bits are associated with a distribution level of encoding, and wherein a plurality of the blocks of audio information are set aside for encoding by a plurality of distributors of audio information, and wherein a predetermined combination of code bits within the plurality of blocks of audio information indicates audio information that has not been encoded by one or more of the plurality of distributors.
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17. A method of encoding blocks of audio information, comprising:
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encoding each of the blocks of audio information by modulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to indicate first and second levels of distribution without substantially eliminating a portion of the audio at one of the first and second frequencies, wherein at least some of the blocks of audio information are encoded to contain distribution level information and audio signal information at each of the selected first and second frequencies, and wherein the selected first and second frequencies change from a first one of the blocks of audio information to a second one of the blocks of audio information; encoding, by use of a primary encoder, a first group of the blocks of audio information with a synchronization sequence, wherein the primary encoder leaves at least second and third groups of the blocks of audio information unencoded; encoding the second group of the blocks of audio information to identify a first distributor of the audio information; and encoding the third group of the blocks of audio information to identify a second distributor of the audio information. - View Dependent Claims (18, 19)
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20. A method of encoding blocks of audio information, comprising:
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encoding each of the blocks of audio information by modulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to indicate first and second levels of distribution without substantially eliminating a portion of the audio at one of the first and second frequencies, wherein at least some of the blocks of audio information are encoded to contain distribution level information and audio signal information at each of the selected first and second frequencies, and wherein the selected first and second frequencies change from a first one of the blocks of audio information to a second one of the blocks of audio information, wherein encoding each of the blocks of audio information includes; increasing the spectral power at one of the first and second frequencies of each block of audio information to render the spectral power at the one of the first and second frequencies a local maximum; and decreasing the spectral power at the other of the first and second frequencies of each block of audio information to render the spectral power at the other of the first and second frequencies a local minimum.
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21. A method of encoding blocks of audio information, comprising:
encoding each of the blocks of audio information by modulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to indicate first and second levels of distribution without substantially eliminating a portion of the audio at one of the first and second frequencies, wherein at least some of the blocks of audio information are encoded to contain distribution level information and audio signal information at each of the selected first and second frequencies, and wherein the selected first and second frequencies change from a first one of the blocks of audio information to a second one of the blocks of audio information, wherein encoding each of the blocks of audio information includes selectively changing a phase relationship between the first and second frequencies in each of the blocks of audio information.
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22. A method of encoding blocks of audio information, comprising:
encoding each of the blocks of audio information by modulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to indicate first and second levels of distribution without substantially eliminating a portion of the audio at one of the first and second frequencies, wherein at least some of the blocks of audio information are encoded to contain distribution level information and audio signal information at each of the selected first and second frequencies, and wherein the selected first and second frequencies change from a first one of the blocks of audio information to a second one of the blocks of audio information, wherein encoding each of the blocks of audio information includes swapping, in each of the blocks of audio information, a spectral amplitude of at least one of the first and second frequencies with a spectral amplitude of a frequency having a maximum amplitude in a frequency neighborhood of the at least one of the first and second frequencies.
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23. A method of encoding blocks of audio information, comprising:
encoding each of the blocks of audio information by modulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to indicate first and second levels of distribution without substantially eliminating a portion of the audio at one of the first and second frequencies, wherein at least some of the blocks of audio information are encoded to contain distribution level information and audio signal information at each of the selected first and second frequencies, and wherein the selected first and second frequencies change from a first one of the blocks of audio information to a second one of the blocks of audio information, wherein the first and second frequencies change based on low frequency maxima.
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24. A method of encoding blocks of audio information, comprising:
encoding each of the blocks of audio information by modulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to indicate first and second levels of distribution without substantially eliminating a portion of the audio at one of the first and second frequencies, wherein at least some of the blocks of audio information are encoded to contain distribution level information and audio signal information at each of the selected first and second frequencies, wherein the selected first and second frequencies change from a first one of the blocks of audio information to a second one of the blocks of audio information, and wherein a synchronization block characterized by a triple tone portion is added to the audio information.
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25. A method for decoding first and second blocks of audio information associated with at least a portion of an audio signal to recover corresponding first and second code portions therefrom, comprising:
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detecting first and second frequencies from a frequency spectrum associated with the first block of audio information; demodulating a characteristic of the audio signal at the first and second frequencies to recover the first code portion from the first block of audio information, wherein the first block of audio information contains information associated with the audio signal and information associated with the first code portion encoded at each of the first and second frequencies without substantially eliminating a portion of the audio signal at one of the first and second frequencies; detecting third and fourth frequencies from a frequency spectrum associated with the second block of audio information, wherein the third and fourth frequencies are offset from the first and second frequencies; and demodulating a characteristic of the audio signal at the third and fourth frequencies to recover the second code portion from the second block of audio information, wherein the second block of audio information contains information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein demodulating the characteristic of the audio signal at the first and second frequencies includes demodulating the first and second frequencies so that the first code portion has a value dependent upon which of the first and second frequencies is a local maximum and which of the first and second frequencies is a local minimum; and
wherein demodulating the characteristic of the audio signal at the third and fourth frequencies includes demodulating the third and fourth frequencies so that the second code portion has a value dependent upon which of the third and fourth frequencies is a local maximum and which of the third and fourth frequencies is a local minimum.
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26. A method for decoding first and second blocks of audio information associated with at least a portion of an audio signal to recover corresponding first and second code portions therefrom, comprising:
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detecting first and second frequencies from a frequency spectrum associated with the first block of audio information; demodulating a characteristic of the audio signal at the first and second frequencies to recover the first code portion from the first block of audio information, wherein the first block of audio information contains information associated with the audio signal and information associated with the first code portion encoded at each of the first and second frequencies without substantially eliminating a portion of the audio signal at one of the first and second frequencies; detecting third and fourth frequencies from a frequency spectrum associated with the second block of audio information, wherein the third and fourth frequencies are offset from the first and second frequencies; and demodulating a characteristic of the audio signal at the third and fourth frequencies to recover the second code portion from the second block of audio information, wherein the second block of audio information contains information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein demodulating the characteristic of the audio signal at the first and second frequencies includes demodulating the first and second frequencies based on a phase relationship between the first and second frequencies, and wherein demodulating the characteristic of the audio signal at the third and fourth frequencies includes demodulating the third and fourth frequencies based on a phase relationship between the third and fourth frequencies.
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27. A method for decoding first and second blocks of audio information associated with at least a portion of an audio signal to recover corresponding first and second code portions therefrom, comprising:
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detecting first and second frequencies from a frequency spectrum associated with the first block of audio information; demodulating a characteristic of the audio signal at the first and second frequencies to recover the first code portion from the first block of audio information, wherein the first block of audio information contains information associated with the audio signal and information associated with the first code portion encoded at each of the first and second frequencies without substantially eliminating a portion of the audio signal at one of the first and second frequencies; detecting third and fourth frequencies from a frequency spectrum associated with the second block of audio information, wherein the third and fourth frequencies are offset from the first and second frequencies; and demodulating a characteristic of the audio signal at the third and fourth frequencies to recover the second code portion from the second block of audio information, wherein the second block of audio information contains information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein demodulating the characteristic of the audio signal at the first and second frequencies includes demodulating the first and second frequencies based on a swapping of a spectral amplitude of at least one of the first and second frequencies with a spectral amplitude of a frequency having a maximum amplitude in a frequency neighborhood of the least one of the first and second frequencies, and wherein demodulating the characteristic of the audio signal at the third and fourth frequencies includes demodulating the third and fourth frequencies based on a swapping of a spectral amplitude of at least one of the third and fourth frequencies with a spectral amplitude of a frequency having a maximum amplitude in a frequency neighborhood of the least one of the third and fourth frequencies.
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28. A method for decoding first and second blocks of audio information associated with at least a portion of an audio signal to recover corresponding first and second code portions therefrom, comprising:
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detecting first and second frequencies from a frequency spectrum associated with the first block of audio information; demodulating a characteristic of the audio signal at the first and second frequencies to recover the first code portion from the first block of audio information, wherein the first block of audio information contains information associated with the audio signal and information associated with the first code portion encoded at each of the first and second frequencies without substantially eliminating a portion of the audio signal at one of the first and second frequencies; detecting third and fourth frequencies from a frequency spectrum associated with the second block of audio information, wherein the third and fourth frequencies are offset from the first and second frequencies; and demodulating a characteristic of the audio signal at the third and fourth frequencies to recover the second code portion from the second block of audio information, wherein the second block of audio information contains information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein the offset between the first and second frequencies and the third and fourth frequencies is determined by frequency hopping based on a change in a low frequency maximum.
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29. A method for decoding first and second blocks of audio information associated with at least a portion of an audio signal to recover corresponding first and second code portions therefrom, comprising:
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detecting first and second frequencies from a frequency spectrum associated with the first block of audio information; demodulating a characteristic of the audio signal at the first and second frequencies to recover the first code portion from the first block of audio information, wherein the first block of audio information contains information associated with the audio signal and information associated with the first code portion encoded at each of the first and second frequencies without substantially eliminating a portion of the audio signal at one of the first and second frequencies; detecting third and fourth frequencies from a frequency spectrum associated with the second block of audio information, wherein the third and fourth frequencies are offset from the first and second frequencies; and demodulating a characteristic of the audio signal at the third and fourth frequencies to recover the second code portion from the second block of audio information, wherein the second block of audio information contains information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies, wherein the first and second frequencies are determined according to a reference frequency, a low frequency maximum and a shift index. - View Dependent Claims (30)
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31. A method for decoding first and second blocks of audio information associated with at least a portion of an audio signal to recover corresponding first and second code portions therefrom, comprising:
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detecting first and second frequencies from a frequency spectrum associated with the first block of audio information; demodulating a characteristic of the audio signal at the first and second frequencies to recover the first code portion from the first block of audio information, wherein the first block of audio information contains information associated with the audio signal and information associated with the first code portion encoded at each of the first and second frequencies without substantially eliminating a portion of the audio signal at one of the first and second frequencies; detecting third and fourth frequencies from a frequency spectrum associated with the second block of audio information, wherein the third and fourth frequencies are offset from the first and second frequencies; demodulating a characteristic of the audio signal at the third and fourth frequencies to recover the second code portion from the second block of audio information, wherein the second block of audio information contains information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies; and detecting a synchronization message from a plurality of blocks of audio information associated with the audio signal, wherein the synchronization message is characterized by a triple tone portion.
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32. A method for decoding first and second blocks of audio information associated with at least a portion of an audio signal to recover corresponding first and second code portions therefrom, comprising:
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detecting first and second frequencies from a frequency spectrum associated with the first block of audio information; demodulating a characteristic of the audio signal at the first and second frequencies to recover the first code portion from the first block of audio information, wherein the first block of audio information contains information associated with the audio signal and information associated with the first code portion encoded at each of the first and second frequencies without substantially eliminating a portion of the audio signal at one of the first and second frequencies; detecting third and fourth frequencies from a frequency spectrum associated with the second block of audio information, wherein the third and fourth frequencies are offset from the first and second frequencies; demodulating a characteristic of the audio signal at the third and fourth frequencies to recover the second code portion from the second block of audio information, wherein the second block of audio information contains information associated with the audio signal and information associated with the second code portion at each of the third and fourth frequencies; decoding a plurality of blocks of audio information to recover a plurality of code portions; and decoding one or more of the plurality of code portions to determine a distribution level of the audio information, wherein a particular combination of the one of more code portions indicates that a corresponding group of blocks of audio information has not been encoded by a distributor of the audio information.
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33. A method of decoding blocks of audio information, comprising:
decoding each of the blocks of audio information to recover a corresponding code portion by demodulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to identify first and second distributors of audio information, wherein at least some of the blocks of audio information contain distribution level information and audio signal information encoded at each of the selected first and second frequencies without substantially eliminating a portion of the audio information at one of the first and second frequencies, and wherein the selected first and second frequencies change from a first block of audio information to a second block of audio information, wherein decoding each of the blocks of audio information includes decoding one or more of the code portions to determine a distribution level of encoding, and wherein a number of blocks of audio information are set aside for encoding by a same number of distributors of the audio information, and wherein decoding each of the blocks of audio information includes decoding a predetermined combination of the code portions to determine that a corresponding group of blocks of audio information has not been encoded by a distributor.
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34. A method of decoding blocks of audio information, comprising:
decoding each of the blocks of audio information to recover a corresponding code portion by demodulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to identify first and second distributors of audio information, wherein at least some of the blocks of audio information contain distribution level information and audio signal information encoded at each of the selected first and second frequencies without substantially eliminating a portion of the audio information at one of the first and second frequencies, wherein the selected first and second frequencies change from a first block of audio information to a second block of audio information, and wherein decoding each of the blocks of audio information includes demodulating the first and second frequencies to recover a code having a value dependent upon which of the first and second frequencies is a local maximum and which of the first and second frequencies is a local minimum.
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35. A method of decoding blocks of audio information, comprising:
decoding each of the blocks of audio information to recover a corresponding code portion by demodulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to identify first and second distributors of audio information, wherein at least some of the blocks of audio information contain distribution level information and audio signal information encoded at each of the selected first and second frequencies without substantially eliminating a portion of the audio information at one of the first and second frequencies, wherein the selected first and second frequencies change from a first block of audio information to a second block of audio information, and wherein demodulating the audio at the first and second frequencies includes recovering a code portion having a value dependent upon a phase relationship between the first and second frequencies.
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36. A method of decoding blocks of audio information, comprising:
decoding each of the blocks of audio information to recover a corresponding code portion by demodulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to identify first and second distributors of audio information, wherein at least some of the blocks of audio information contain distribution level information and audio signal information encoded at each of the selected first and second frequencies without substantially eliminating a portion of the audio information at one of the first and second frequencies, wherein the selected first and second frequencies change from a first block of audio information to a second block of audio information, and wherein demodulating the audio at the first and second frequencies includes demodulating the first and second frequencies based on a swapping of a spectral amplitude of at least one of the first and second frequencies with a spectral amplitude of a frequency having a maximum amplitude in a frequency neighborhood of the least one of the first and second frequencies to recover a code.
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37. A method of decoding blocks of audio information, comprising:
decoding each of the blocks of audio information to recover a corresponding code portion by demodulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to identify first and second distributors of audio information, wherein at least some of the blocks of audio information contain distribution level information and audio signal information encoded at each of the selected first and second frequencies without substantially eliminating a portion of the audio information at one of the first and second frequencies, wherein the selected first and second frequencies change from a first block of audio information to a second block of audio information, and wherein the first and second frequencies are changed based on low frequency maxima.
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38. A method of decoding blocks of audio information, comprising:
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decoding each of the blocks of audio information to recover a corresponding code portion by demodulating a characteristic of the audio within the corresponding block of audio information at selected first and second frequencies to identify first and second distributors of audio information, wherein at least some of the blocks of audio information contain distribution level information and audio signal information encoded at each of the selected first and second frequencies without substantially eliminating a portion of the audio information at one of the first and second frequencies, and wherein the selected first and second frequencies change from a first block of audio information to a second block of audio information; and decoding a synchronization message characterized by a triple tone portion.
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39. A method of encoding a signal, comprising:
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measuring a characteristic of the signal at a plurality of frequencies associated with the signal; modulating the signal at one or more of the plurality of frequencies if the characteristic of the signal at the one or more of the plurality of frequencies is not one of a local minimum or a local maximum; and foregoing modulating the signal at the one or more of the plurality of frequencies if the characteristic of the signal at the one or more of the plurality of frequencies is one of the local minimum or the local maximum. - View Dependent Claims (40, 41, 42, 43)
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Specification