Audio signal processing

About: Audio signal processing is a research topic. Over the lifetime, 21463 publications have been published within this topic receiving 319597 citations. The topic is also known as: audio processing & Acoustic signal processing.

Reflected sound rendering for object-based audio

Abstract: Embodiments are described for rendering spatial audio content through a system that is configured to reflect audio off of one or more surfaces of a listening environment. The system includes an array of audio drivers distributed around a room, wherein at least one driver of the array of drivers is configured to project sound waves toward one or more surfaces of the listening environment for reflection to a listening area within the listening environment and a renderer configured to receive and process audio streams and one or more metadata sets that are associated with each of the audio streams and that specify a playback location in the listening environment.

Digital PWM amplifier with simulation-based feedback

Abstract: Systems and methods for performance improvements in digital switching amplifiers using simulation-based feedback. In one embodiment, a digital pulse width modulation (PWM) amplifier includes a signal processing plant configured to receive and process an input audio signal. The amplifier also includes a simulator configured to model processing of audio signals by the plant. The outputs of the plant and the simulator are provided to a subtractor, the output of which is then added to the input audio signal as feedback. The plant may consist of a modulator and power switch, a noise shaper, or any other type of plant. An analog-to-digital converter (AOC) may be provided to convert the output audio signal to a digital signal for input to the subtracter. Filtering may be implemented before or after the ADC, and a decimator may be placed after the ADC if it is an oversampling ADC.

Audio coding using downmix

Abstract: An Audio decoder for decoding a multi-audio-object signal having an audio signal of a first type and an audio signal of a second type encoded therein is described, the multi-audio-object signal consisting of a downmix signal (56) and side information (58), the side information comprising level information (60) of the audio signal of the first type and the audio signal of the second type in a first predetermined time/frequency resolution (42), and a residual signal (62) specifying residual level values in a second predetermined time/frequency resolution, the audio decoder comprising means (52) for computing prediction coefficients (64) based on the level information (60); and means (54) for up-mixing the downmix signal (56) based on the prediction coefficients (64) and the residual signal (62) to obtain a first up-mix audio signal approximating the audio signal of the first type and/or a second up-mix audio signal approximating the audio signal of the second type.

Apparatus and method for stereo audio encoding of digital audio signal data

Abstract: A stereo audio encoding method for encoding left and right original signals to a left and right reproduced signals for suppressing a loss of quality in the reproduced audio signal. The correlation between the right and left channel signals is determined, and the phase of each signal is compared. If the two signals have the same phase, a modified scale factor is calculated based on a power equalization method, but if the two signals are in opposite phase, another modified scale factor is calculated based on an error minimization method. The modified scale factors are used for calculating the reproduced signals.

Cyclic tempogram—A mid-level tempo representation for musicsignals

Abstract: The extraction of local tempo and beat information from audio recordings constitutes a challenging task, particularly for music that reveals significant tempo variations. Furthermore, the existence of various pulse levels such as measure, tactus, and tatum often makes the determination of absolute tempo problematic. In this paper, we present a robust mid-level representation that encodes local tempo information. Similar to the well-known concept of cyclic chroma features, where pitches differing by octaves are identified, we introduce the concept of cyclic tempograms, where tempi differing by a power of two are identified. Furthermore, we describe how to derive cyclic tempograms from music signals using two different methods for periodicity analysis and finally sketch some applications to tempo-based audio segmentation.