In one aspect, an example method for outputting an alert indicating a functional state of a back-up audio-broadcast system involves: a computing device receiving a first audio-stream that represents first audio-content; the computing device generating a first signature based, at least in part, upon an extent of single-channel/multi-channel transitions included within the first audio-content; the computing device receiving a second audio-stream that represents second audio-content; the computing device generating a second signature based, at least in part, upon an extent of single-channel/multi-channel transitions included within the second audio-content; the computing device making a determination that the generated first-signature and the generated second-signature lack a threshold extent of similarity; and responsive to the determination that the generated first-signature and the generated second-signature lack the threshold extent of similarity, the computing device outputting an alert.

In one aspect, an example method for outputting an alert indicating a functional state of a back-up audio-broadcast system involves: a computing device receiving a first audio-stream that represents first audio-content; the computing device generating a first signature based, at least in part, upon an extent of single-channel/multi-channel transitions included within the first audio-content; the computing device receiving a second audio-stream that represents second audio-content; the computing device generating a second signature based, at least in part, upon an extent of single-channel/multi-channel transitions included within the second audio-content; the computing device making a determination that the generated first-signature and the generated second-signature lack a threshold extent of similarity; and responsive to the determination that the generated first-signature and the generated second-signature lack the threshold extent of similarity, the computing device outputting an alert.

On the basis of a bitstream (P), an n-channel audio signal (X) is reconstructed by deriving an m-channel core signal (Y) and multichannel coding parameters () from the bitstream, where 1m<n. Also derived from the bitstream are pre-processing dynamic range control, DRC, parameters (DRC2) quantifying an encoder-side dynamic range limiting of the core signal. The n-channel audio signal is obtained by parametric synthesis in accordance with the multichannel coding parameters and while cancelling any encoder-side dynamic range limiting based on the pre-processing DRC parameters. In particular embodiments, the reconstruction further includes use of compensated post-processing DRC parameters quantifying a potential decoder-side dynamic range compression. Cancellation of an encoder-side range limitation and range compression are preferably performed by different decoder-side components. Cancellation and compression may be coordinated by a DRC pre-processor.

An input ambisonic audio signal includes multiple channels, each of which is made up of audio data representing sound captured by an ambisonic microphone. A remote audio signal made up of audio data representing sound captured by remote meeting equipment is output by a local loudspeaker. Acoustic echo cancellation is performed on the input ambisonic audio signal by removing the remote audio signal from the input ambisonic audio signal. The acoustic echo cancellation may be performed on ambisonic A-format or B-format encoded audio data, or on an output encoding generated from the B-format encoded audio data. Comfort noise may be generated based on spectral and spatial characteristics of noise in the input audio data, for insertion into the input signal during acoustic echo cancellation. Automatic gain control may be performed across the multiple channels of the input audio signal.

This document describes techniques for synchronizing rendering of multi-channel audio output. First audio data corresponding to a first audio channel and second audio data corresponding to a second audio channel may be received. The first and second audio data may be configured for simultaneous rendering. A transmission schedule for wirelessly transmitting audio data to each of first and second audio rendering devices may be configured, according to which the first audio data may be scheduled for transmission to the first audio rendering device after the second audio data is scheduled for transmission to the second audio rendering device by a first length of time. An indication may be wirelessly transmitted to the second audio rendering device to delay rendering audio data by the first length of time. The first and second audio data may be wirelessly transmitted to the first and second audio rendering devices according to the transmission schedule.

This document describes techniques for synchronizing rendering of multi-channel audio output. First audio data corresponding to a first audio channel and second audio data corresponding to a second audio channel may be received. The first and second audio data may be configured for simultaneous rendering. A transmission schedule for wirelessly transmitting audio data to each of first and second audio rendering devices may be configured, according to which the first audio data may be scheduled for transmission to the first audio rendering device after the second audio data is scheduled for transmission to the second audio rendering device by a first length of time. An indication may be wirelessly transmitted to the second audio rendering device to delay rendering audio data by the first length of time. The first and second audio data may be wirelessly transmitted to the first and second audio rendering devices according to the transmission schedule.

A process and system for generating three dimensional sound conferencing includes generating a virtual map with a plurality of positions, each participant selecting one of the positions, determining a direction from each position to each other position on the map, determining a distance from each position to each other position on the map, receiving sound from each participant, mixing the received sound, transforming the mixed sound into binaural audio, and directing the binaural audio sound to each participant via a speaker associated with the virtual position of the speaking participant. The result is a clarified sound that gives to the listening participant a sense of where the speaking participant is positioned relative to the listening participant.

Songs titles and song artists or other content received on an HD-radio are cross-referenced to one or more geographic locations where they were heard on the radio by identifying a song title or artist in the HD radio data stream and instructing a global positioning system navigation unit to contemporaneously determine its location. The determined location and song title and/or artist are cross-referenced to each other in a list or database. A touch-sensitive display device is configured to display the location or portion of a route where a listened-to song was heard. Song titles and/or artists can be determined by tactile selection of portions of a route displayed on the map.

Songs titles and song artists or other content received on an HD-radio are cross-referenced to one or more geographic locations where they were heard on the radio by identifying a song title or artist in the HD radio data stream and instructing a global positioning system navigation unit to contemporaneously determine its location. The determined location and song title and/or artist are cross-referenced to each other in a list or database. A touch-sensitive display device is configured to display the location or portion of a route where a listened-to song was heard. Song titles and/or artists can be determined by tactile selection of portions of a route displayed on the map.

Disclosed is a frequency amplitude modulation (FAM) transmission apparatus and method by combining a frequency modulation (FM) signal and a digital modulated amplitude modulation (AM) signal. A FAM transmission method includes receiving an FM signal created by modulating an audio signal that includes audio information for mono or stereo broadcasting based on an FM scheme; receiving a digital pulse created by modulating digital data used to provide an additional service for the mono or stereo broadcasting based on an amplitude modulation (AM) affiliated digital modulation scheme; creating an AM signal by by adjusting the digital pulse to have a value greater than 0; and creating a FAM signal by combining the FM signal and the AM signal.