Audio mixer with automatic gain controller for software based multipoint control unit

V. M. Baskaran, Kok Sheik Wong

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4 Citations (Scopus)


This paper proposes two audio mixing algorithms in software based Multipoint Control Unit (MCU) using Automatic Gain Controller. The objectives of the proposed algorithms include performing selective mixing, minimizing audio clipping, assigning higher amplitude priority to the loudest speaker and ensuring a smooth transition as the primary speaker changes from one participant to another. The proposed algorithms are able to suppress unexpected signal spikes by considering previously computed gain value(s) in the calculation of the current gain. The proposed algorithms are also able to mix multiple VoIP packets for up to eight conference participants within 150s, which is well below the default RTP audio packet timeframe of 20ms. The proposed mixing algorithms are integrated with the audio decoder and encoder modules to complete theMCU system. Experiments were carried out to verify the basic performances of the proposed mixing algorithms.

Original languageEnglish
Title of host publicationProceedings of the 2010 Asia Pacific Conference on Circuit and System, APCCAS 2010
Number of pages4
Publication statusPublished - 2010
Externally publishedYes
EventIEEE Asia Pacific Conference on Circuits and Systems (APCCAS) 2010 - Kuala Lumpur, Malaysia
Duration: 6 Dec 20109 Dec 2010 (Proceedings)


ConferenceIEEE Asia Pacific Conference on Circuits and Systems (APCCAS) 2010
Abbreviated titleAPCCAS 2010
CityKuala Lumpur
Internet address

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