Multicast Audio Stream Mixing for Conference Systems

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Solution Overview

Problem

Existing audio stream arrangements using unicast transmission for conference systems face inefficiencies in switching active audio devices, leading to potential loss of audio signals due to the need for multiple commands and increased latency in busy networks.

Innovation Solution

Implementing a multicast transmission protocol within an IP network, where audio streams from active devices are sent to a multicast address, allowing for faster switching between active devices with reduced command messages, and enabling efficient real-time audio processing and distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If unicast transmission is used for audio streams from active audio devices, then each audio device can be individually addressed and controlled, but the number of commands required for switching increases and audio signal loss may occur due to latency in busy networks

Engineering Contradiction:
Improveaudio signal transmission reliabilityVSAvoidswitching latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges multiple unicast transmission channels into a single multicast channel. Instead of sending individual audio streams from each active audio device through separate unicast connections to the processing device, all audio streams are combined and transmitted through a single multicast address. This consolidation reduces the number of commands needed for switching and eliminates the latency issues associated with multiple individual command transmissions in busy networks.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If unicast transmission is used, then individual audio device control is maintained, but the number of command messages increases by 50% compared to multicast

Engineering Contradiction:
Improveaudio device control capabilityVSAvoidnumber of command messages
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent combines multiple control commands into a single multicast message. Instead of requiring separate commands to manage each audio device's unicast connection, the system uses a single multicast address that all active audio devices can join. This merging of control mechanisms reduces the total number of command messages by 50% while maintaining the ability to control individual audio devices through the multicast group management protocols.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2939384B1Audio stream arrangement
Publication Date: 2019.02.27 ROBERT BOSCH GMBH
  • EP2939384B1 patent drawingFigure 1

AI summary

Conference systems are often installed in plenary halls and comprise a plurality of microphones for participants of a discussion, whereby the speech signals of the participants are received by the microphones, amplified by the conference system and distributed to the other participants of the discussion. An audio stream arrangement (1) is proposed comprising: a plurality of audio devices (2), whereby each audio device (2) is adapted to provide an audio stream and whereby each audio device (2) comprises an audio device network interface (8) for transmitting its audio stream over a network (5), a control device (4), whereby the control device (4) is adapted to send a command over the network (5) to any of the audio devices (2) to set the audio device (2) in an active state, whereby the audio device (2) in the active state transmits its audio stream over the network (5), a processing device (3) for processing the audio streams from the active audio devices (2), whereby the processing device (3) comprises a processing device network interface (9) for receiving the audio streams from the network (5) and a mixing unit (11) with a plurality of input channels (12) and an output channel (13), whereby each input channel (12) can be assigned to a audio stream from one active audio device (2) and whereby the mixing unit (11) is operable to mix the audio streams from the plurality of input channels (12) into a common audio stream and to output the common audio stream to the output channel (13), whereby the audio streams from the active audio devices (2) to the processing device are transmitted by a multicast transmission.