Abstract: Among other things, techniques and systems are disclosed for detecting musical structures, such as downbeats. In one aspect, a method performed by a data processing device includes receiving an input audio signal. The method includes detecting a meter in the received audio signal. Detecting the meter includes generating an envelope of the received audio signal; generating an autocorrelation phase matrix having a two-dimensional array based on the generated envelope to identify a dominant periodicity in the received audio signal; and filtering both dimensions of the generated autocorrelation phase matrix to enhance peaks in the two-dimensional array. The meter represents a time signature of the input audio signal having multiple beats. Additionally, the method includes identifying a downbeat as a first beat in the detected meter.

Abstract: Among other things, techniques and systems are disclosed for detecting onsets. On a device, an audio signal is pre-processed in temporal domain. The pre-processed audio signal is smoothed on the device. A predetermined quantity of peaks is selectively identified in the pre-processed and smoothed audio signal based on a size of a sample window applied to the pre-processed and smoothed audio signal.

Abstract: An adaptive operating system is described that adjusts a set of applications and/or a set of application icons presented on a user interface based on ambient noise and/or ambient light conditions at the mobile device. In some implementations, a sensor on a mobile device can detect the amount of ambient noise and/or light at the mobile device and adjust the presentation of sound-related and/or light-related applications or application icons on a graphical interface of the mobile device. In some implementations, a set of applications and/or a set of application icons presented on a user interface can be adjusted based on movement of the mobile device detected by a motion sensor of the mobile device.

Abstract: Among other things, techniques and systems are disclosed for detecting musical structures, such as downbeats. In one aspect, a method performed by a data processing device includes receiving an input audio signal. The method includes detecting a meter in the received audio signal. Detecting the meter includes generating an envelope of the received audio signal; generating an autocorrelation phase matrix having a two-dimensional array based on the generated envelope to identify a dominant periodicity in the received audio signal; and filtering both dimensions of the generated autocorrelation phase matrix to enhance peaks in the two-dimensional array. The meter represents a time signature of the input audio signal having multiple beats. Additionally, the method includes identifying a downbeat as a first beat in the detected meter.

Abstract: Among other things, techniques and systems are disclosed for detecting onsets. On a device, an audio signal is pre-processed in temporal domain. The pre-processed audio signal is smoothed on the device. A predetermined quantity of peaks is selectively identified in the pre-processed and smoothed audio signal based on a size of a sample window applied to the pre-processed and smoothed audio signal.

Abstract: New methods and software tools that simulate interacting with geometric shapes to synthesize sound are provided. The invention includes methods for determining real-time resonant frequencies for shape-changing geometric objects and interactive software articles/systems that allow users to simulate in real time resonant frequencies of an object as changes are made to its geometry and other sound input parameters.