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US 8,476,518 B2Granted
System and method for generating audio wavetables
AssigneeSTMicroelectronics Asia Pacific Pte Ltd
InventorsKabi P. Padhi, Jianhua Sun
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Abstract
A method includes receiving an audio signal and identifying one or more steady-state segments of the audio signal. The method also includes identifying at least one portion of the one or more segments that contains a specified frequency. Further, the method includes generating a wavetable using the at least one identified portion of the one or more segments. In addition, the method could include synthesizing an output audio signal using the wavetable. The output audio signal could represent a ringtone in a mobile telephone.
Claims31
A method, comprising:
- in response to receiving an audio signal comprising at least a steady-state segment preceded by a first transient segment and followed by a second transient segment, identifying peaks in the received audio signal having an amplitude higher than signals at neighboring frequencies;
- selecting a subset of the identified peaks between a start and an end of the steady-state segment within the received audio, the subset of identified peaks corresponding to trajectories that last over a specified number of frames;
- identifying at least one pitch frequency and amplitude within the steady-state segment of the received audio signal based on the subset of the identified peaks;
- identifying and selecting a portion of the steady-state segment that (a) contains the pitch frequency and (b) begins and ends at zero crossover points;
- responsive to selection of the identified portion of the steady-state segment, generating a wavetable using audio samples of the received audio signal within the selected portion of the steady-state segment, wherein looping one or more of the audio samples stored in the wavetable synthesizes an output audio signal corresponding to the steady-state segment.
2 more elements
An apparatus, comprising:
- an audio decomposer configured to identify one or more steady-state segments of a received audio signal comprising at least a steady-state segment preceded by a first transient segment and followed by a second transient segment;
- a wavetable generator configured to:
- identify peaks in the received audio signal having an amplitude higher than signals at neighboring frequencies;
- select a subset of the identified peaks between a start and an end of the steady-state segment within the received audio, the subset of identified peaks corresponding to trajectories that last over a specified number of frames;
- identify at least one pitch frequency and amplitude within the steady-state segment of the received audio signal based on the subset of the identified peaks;
- identify and select at least one portion of the steady-state segment that (a) contains the pitch frequency and (b) begins and ends at zero crossover points;
- and
- generate a wavetable using audio samples of the received audio signal within the at least one identified portion of the steady-state segment, wherein looping the audio samples synthesizes an output audio signal corresponding to the steady-state segment;
- and
- a memory configured to store the wavetable.
7 more elements
An apparatus, comprising:
- one or more processors collectively configured to:
- in response to receiving an audio signal comprising at least a steady-state segment preceded by a first transient segment and followed by a second transient segment, identify the steady-state segment of a received audio signal by:
- identifying peaks in the received audio signal having an amplitude higher than signals at neighboring frequencies, and
- selecting a subset of the identified peaks between a start and an end of the steady-state segment within the received audio, the subset of identified peaks corresponding to trajectories that last over a specified number of frames;
- identify at least one pitch frequency and amplitude within the steady-state segment of the received audio signal based on the subset of the identified peaks;
- based on the subset of the identified peaks, identify and select at least one portion of the steady-state segment that contains the pitch frequency and begins and ends at zero crossover points;
- and
- generate a wavetable using audio samples of the received audio signal within the at least one identified portion of the steady-state segment, wherein looping audio samples stored in the wavetable synthesizes an output audio signal corresponding to the steady-state segment;
- and
- a memory configured to store the wavetable.
7 more elements
A computer program product embodied on a computer readable medium and capable of being executed by a processor, the computer program comprising computer readable program code for:
- in response to receiving an audio signal comprising at least a steady-state segment preceded by a first transient segment and followed by a second transient segment, identifying the steady-state segment of a received audio signal by:
- identifying peaks in the received audio signal having an amplitude higher than signals at neighboring frequencies,
- selecting a subset of the identified peaks between a start and an end of the steady-state segment within the received audio, the subset of identified peaks corresponding to trajectories that last over a specified number of frames;
- identifying at least one pitch frequency and amplitude within the steady-state segment of the received audio signal based on the subset of the identified peaks;
- identifying at least one portion of the steady-state segment that contains the pitch frequency and begins and ends at zero crossover points;
- generating a wavetable using audio samples of the received audio signal within the at least one identified portion of the steady-state segment, wherein looping the audio samples synthesizes an output audio signal corresponding to the steady-state segment.
3 more elements
Dependencies are inferred from the claim text.