Harman International Industries, Inc.

Robert Boatright

Aaron Gelter

Brian R Parker

Richard Allen Kreifeldt

Jeffrey L Hutchings

Craig Gunther

A network communication system includes a central control system that may transmit a request packet over a network to an apparatus that is configured to operate in an alarm system. The alarm system may be configured in accordance with a standard or protocol. The request packet may include instructions that instruct the apparatus to perform one or more tests that determine whether the apparatus is compliant with the standard or protocol. The apparatus may be configured to receive the packet from over the network and perform the tests in accordance with the instructions. The apparatus may report test results of the tests to the central control system by sending a reply packet that includes the test results over the network to the central control system.

System for remote installed sound compliance testing

A network communication system includes a talker that may communicate a data stream having an optimal presentation time to a plurality of listeners over a network, such as an Ethernet Audio/Video Bridging network. The optimal presentation time may be determined by a maximum latency among a plurality of latencies for connections between the talker and the listeners. A controller may communicate with the listeners to determine the maximum latency. The controller may also provide the maximum latency to the talker and the listeners. The talker may determine the optimal presentation time based on the maximum latency. The listeners may allocate an optimum amount of resources to buffer the data stream before the data in the data stream is presented.

System for optimizing latency in an AVB network

A system generates one or more media streams from time-stamped packets received over a network. The packets may include audio, video, or a combination of both, sampled at a rate determined by a master media clock at a transmitter of the time-stamped packets or at some other node on the network. Timestamps in the packets may be presentation times based on values of a remote real-time clock at the transmitter that is synchronized with a local real-time clock at a receiver. The system may generate the media streams from the media stream samples and present the sampled data according to the presentation times.

Media extractor

A system may route media stream samples in time-stamped packets to a media interface. The system may determine a hash value from a stream identifier that identifies a source media stream corresponding to the media stream samples. The hash value may be determined based on a combination of a first portion of the stream identifier and a second portion of the stream identifier. The system may determine whether the stream identifier identifies a subscribed media stream by looking up the hash value in a hash table. The system may route the media stream samples to a media interface if source media stream is a subscribed media stream.

Stream identifier hash table

A memory management unit (MMU) may buffer media stream samples of one or more media streams, such as audio and/or video streams, in a buffer. The MMU may determine how much time a media stream sample is to be buffered by comparing a value of a real-time clock with a timestamp associated with the media stream sample. The MMU may determine a target output block in the buffer for the media stream sample based on the period of a media clock and on the amount of buffer time that the media stream sample is to be buffered. The target output block is determined relative to an output block identified by a read address. The MMU may store the media stream sample in the target output block. The MMU may increase or decrease the read address at a rate determined by the media clock.

Memory management unit

A system recovers a local media clock from a master media clock based on time-stamped packets received from a transmitter. The packets may include audio, video, or a combination of both, sampled at a rate determined by the master media clock at the transmitter. Timestamps in the packets may be based on values of a remote real-time counter at the transmitter that is synchronized with a local real-time counter at a receiver. The local media clock may be syntonized with the master media clock through the clock periods. The clocks may be synchronized by syntonizing the clocks and adjusting the phase of the local media clocks based on timestamps and a real-time counter.

Media clock recovery

A ring based network includes a first circuit and a second circuit. The first circuit selects one of a number of inputs and switches an input to a first common communication line. A second circuit selects one of a second number of inputs and switches a second input to a second common communication line linked to one of the first number of inputs. A detect circuit controls the switches of the first and second circuit to emulate a communication ring in which nodes are connected in series in a communication loop.

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Sandy, UT, United States of America

Robert Boatright