Mapped meta-data sound-playback device and audio-sampling/sample-processing system usable therewith
View Patent ↗Audio samples corresponding to audio extracts or whole audio titles are automatically mapped to triggers 12 in a playable sound-producing device 1 , the mapping being dependent on the meta-data associated with the audio samples. Thus, a user can play the sound-producing device and generate sounds derived from his favorite audio titles. It is possible to define different mappings between the audio samples and the playable domain of the sound-producing device: an audio sample selector 50 can select between different possible samples for playback by comparing the audio properties of the samples and the play-mode and/or characteristics of the user's performance. An audio sampler/sample-processor 70 can automatically extract segments of an audio source file and map them to triggers in the sound-producing device 1.
1. An audio-sampler/sample-processor for preparing audio units for playback in a sample-based sound-producing device, the sound-producing device having a plurality of operable, physical control elements each of which, when operated by a user, causes a sound to be generated based on an audio unit, the audio-sampler/sample-processor comprising:
an input module for receiving an audio file;
an audio-unit extractor for defining a set of audio units, automatically, by sampling within the input audio file, the audio-unit extractor itself setting the start and end points of each audio unit of said set of audio units;
an analyzer for analyzing said audio units, automatically, to determine the acoustic properties thereof and for defining data descriptive of the determined acoustic properties of each audio unit; and
a mapping module for defining, automatically, a mapping of extracted audio units to the physical control elements of the sample-based sound-producing device, said mapping being dependent on at least part of said data, determined by the analyzer, descriptive of the acoustic properties of the extracted audio unit and on a mapping function defining a condition holding on audio-unit meta-data;
wherein the audio-sampler/sample-processor is configured such that, when coupled to said sample-based sound-producing device, an user operation of one of said physical control elements of the sample-based sound-producing device causes an output of sound corresponding to an extracted audio unit mapped, by the mapping module, to the one of said physical control elements.
2. An audio-sampler/sample-processor according to claim 1 , wherein the analyzer comprises a pitch-detecting module for determining the pitch of an extracted audio unit, and the mapping module is adapted to map an extracted audio unit to one or more of said physical control elements dependent on the pitch of the extracted audio unit.
3. An audio-sampler/sample-processor according to claim 2 , wherein the pitch-detecting module comprises a bank of band-pass filters and a harmonic-pattern analyzer for analyzing the pattern of harmonics in the output from the bank of bandpass filters.
4. An audio-sampler/sample-processor according to claim 1 , wherein the audio-unit extractor comprises a filter-bank mimicking the frequency resolution and frequency response of the human ear, a spectrum generator for generating the short-term spectrum of the audio unit after passage through said filter-bank, a waveform analyzer for analyzing the energy variations of the music's waveform and a spectrum analyzer for analyzing the maxima and minima of said short-term spectrum.
5. An audio-sampler/sample-processor according to claim 1 , and comprising a stability zone detector for detecting zones of spectral stability in the extracted audio units and generating data identifying said zones of spectral stability.
6. An audio-sampler/sample-processor according to claim 1 , and comprising output means for outputting to a memory, a network, or a storage medium: data representative of the extracted audio units, data indicative of the mapping of extracted audio units to operable triggers of said sound-producing device and data descriptive of the acoustic properties of the extracted audio units.
7. A playable sample-based sound-producing device, comprising:
an audio-sampler/sample-processor according to claim 1 ;
a set of operable, physical control elements each of which, when operated by a user, causes a sound to be generated based on an audio unit; and
an audio unit selector adapted to respond to operation of one of said physical control elements by selecting for playback one of the audio units extracted from an audio file by said audio sampler/sample-processor, said selected audio unit being mapped to said one of the physical control elements by said mapping means.
8. The playable sample-based sound-producing device according to claim 7 , wherein the audio unit selector is adapted to select between a plurality of different extracted audio units mapped to the same one of said physical control elements, said selection comprising matching the acoustic properties of said plurality of different extracted audio units with data indicative of the way in which said physical control element was operated by the user.
9. The playable sample-based sound-producing device according to claim 8 , and comprising a time adjuster for causing the duration of playback of an extracted audio unit to differ from the duration of said extracted audio unit, wherein the time adjuster comprises a phase vocoder adapted, in the case where the time adjuster is causing the duration of playback of the extracted audio unit to be longer than the duration of said audio unit, to synthesize extra frames and interpolate said extra frames between frames of said extracted audio unit only in spectrally-stable zones of said extracted audio unit.