Imagination Technologies Limited

Sowmya Mannava

Senthil Kumar Mani

Bala Manikya Prasad Puram

A method of transmitting data determines a measure of consecutive packet loss in a network; a ratio of a number of data packets and a number of error correction packets is selected in dependence on the measure. A stream of data packets is generated, and a stream of error correction packets is generated in dependence on the stream of data packets such that the proportion of error correction packets generated to the data packets generated is commensurate with the selected ratio.

Method and device for transmitting a data stream with selectable ratio of error correction packets to data packets

Method and apparatus for processing a received sequence of data packets by removing unsuitable error correction packets from the sequence

A controller for an acoustic echo canceller includes a noise estimator configured to estimate a level of noise that is comprised in a microphone signal relative to an echo component, estimated by the acoustic echo canceller, comprised in the microphone signal. The controller further includes a control module configured to control the acoustic echo canceller in dependence on that estimate.

Estimating averaged noise component in a microphone signal

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A controller for an acoustic echo canceller is described. The controller includes a noise estimator configured to estimate a level of noise that is comprised in a microphone signal relative to an echo component, estimated by the acoustic echo canceller, comprised in the microphone signal. The controller further includes a control module configured to control the acoustic echo canceller in dependence on that estimate.

Controlling operational characteristics of acoustic echo canceller

An echo path monitoring system for controlling an adaptive filter configured to estimate an echo of a far-end signal comprised in a microphone signal, the system comprising a comparison generator configured to compare the microphone signal with the estimated echo to obtain a first comparison and compare an error signal, which represents a difference between the microphone signal and the estimated echo, with the estimated echo to obtain a second comparison, and a controller configured to combine the first and second comparisons to form a parameter indicative of a state of the microphone signal and, in dependence on said parameter, control an operating mode of the adaptive filter.

Echo path change detector

A system for estimating delay between a far-end signal and an echo of the far-end signal in a microphone signal, the system comprising: a buffer configured to store a time-series of far-end samples representing the far-end signal; a first delay estimator configured to form a first estimate of the delay in respect of a speech frame representing speech in the microphone signal; a second delay estimator configured to form a second estimate of the delay for the speech frame by operating a first set of one or more filters on far-end samples selected from the buffer in dependence on an operating delay; a second set of one or more filters for operation on far-end samples; and a controller configured to, in response to a determination that the first estimate of the delay for the speech frame differs from the operating delay for a previous frame by at least a predefined length of time, cause the one or more filters of the second set to operate on far-end samples selected from the buffer according to the first estimate of the delay and, if in respect of one or more speech frames a measure of convergence of the second set of filters exceeds a measure of convergence of the first set of filters by at least a first predefined threshold, update the operating delay using the first estimate of the delay.

Pure delay estimation

A device for transmitting a media stream over a network, the device comprising: a quality estimator configured to maintain a measure of network quality indicative of available bandwidth over the network; a configuration manager configured to: use the measure of network quality to detect a reduction in network quality indicative of a reduced available bandwidth and, responsive to detecting said reduction, estimate a first bitrate corresponding to the reduced available bandwidth; in response to estimating the first bitrate, determine a second bitrate lower than the first bitrate; and a transceiver configured to transmit the media stream at a transmission bitrate substantially equal to the second bitrate for a first period of time, wherein the configuration manager is further configured to cause an increase of the transmission bitrate from the second bitrate to the first bitrate over a second period of time.

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Hyderabad Telangana, India

Sowmya Mannava