Abstract: Aspects of the subject technology provide improved techniques for determining a state of an audio device, including reduced power techniques for determining if an earbud is currently being worn in a user's ear or not. In aspects, a potential state change in an audio device may be detected, and in response measurement of the state of the device may be initiated, such as by emitting an audio signal and then determining the state of the audio device based on a sensed version of the emitted audio signal.

Abstract: Aspects of the subject technology provide for calibration of audio devices in a case. In some implementations, the calibration techniques may include detecting that an audio device is docked in a case and a lid of the case is in a closed position, where the audio device is positioned in a cavity of the case. In addition, the calibration techniques may include emitting a test audio signal from a speaker of the audio device into the case. The device may include receiving, in response to the test audio signal, a received signal at a sensor inside the case. Moreover, the device may include obtaining a correction for the audio device based on the received signal.

Abstract: Disclosed are systems and methods for performing adaptive equalization operations to reduce variations in the frequency response of audio signals at the eardrum of a wearer of an earphone. The assumption that the frequency response of the error microphone matches the frequency response at the eardrum may not be true due to signal leakage effects and the shape of the ear canal. Techniques are disclosed for the adaptive equalization operations to perform a calibration algorithm to compensate for the effects of the signal leakage and the shape of the ear canal. The earphone may estimate the transfer function from the speaker to the error microphone and may estimate the load impedance from the earphone based on a calibrated relationship between the transfer function and the load impedance. The adaptive equalization may use a calibration algorithm to adjust the frequency response at the error microphone to match that at the eardrum.

Abstract: This disclosure describes systems, methods, and devices related to enhanced validation of video codecs. A device may receive validation results for a video codec using a first computer programming language, the validation results indicative of invocations of functions and conditions of the code; identify, from the validation results, a first validation test that invoked a first function or condition of the code; identify, from the validation results, a second validation test that invoked the first function or condition of the code; determine, from the validation results, that the first validation test and the second validation test overlap in invoking the first function or condition of the code using the first computer programming language; and generate, based on the overlap, a first subset of the validation tests with which to validate code of the video codec using a second computer programming language.

Abstract: A method for audio signal processing of microphone signals of a headphone. An audio signal from a first microphone of a headphone is filtered by an ANC system to produce a first filtered signal. Dynamic range control is performed upon the first filtered signal to produce a first dynamic range adjusted signal that drives a speaker of the headphone. Other aspects are also described and claimed.

Abstract: A method for audio signal processing of microphone signals of a headphone. An audio signal from a first microphone of a headphone is filtered by an ANC system to produce a first filtered signal. Dynamic range control is performed upon the first filtered signal to produce a first dynamic range adjusted signal that drives a speaker of the headphone. Other aspects are also described and claimed.