Each day, millions of users across the globe choose Microsoft Teams to communicate and collaborate. As a result, Microsoft maintains its ongoing efforts to improve the audio and video experiences through the platform. In today’s article we are going to talk about new Teams features that deliver clear sound at frequencies that extend beyond the normal range for speech.
Automatic music detection and High-fidelity music mode are examples of how Teams uses machine learning (ML) and artificial intelligence (AI) to optimize user experiences, delivering improved audio and video quality without taxing your organization’s network.
Communication apps are frequently designed for meetings or 1:1 conversations in which most of the audio signals are speech. Transmitting high-quality speech at the lowest possible bitrate typically requires the use of high-efficiency speech codecs. While these codecs are suitable for their primary purpose, they can significantly limit the fidelity of non-speech signals. High-fidelity music mode in Teams offers superior sound clarity for a wide range of audio content including music and speech.
Superior speech quality in Microsoft Teams
Traditional PSTN (Public Switched Telephone Network) landlines transmit speech in the frequency range from 300Hz to 3.4kHz. The low-end nature of this range poses challenges for hearing differences in letters such as “S” and “F”. However, speech codecs used in today’s telecommunication applications are typically designed for wideband, covering a frequency range of 60Hz to 8kHz, significantly improving the intelligibility of speech compared to traditional phone calls over PSTN.
To enable speech signals with a bandwidth of 8kHz, the raw signal must be sampled at 16kHz at 16bits, which requires 256kbps to transmit. A highly-efficient speech codec can transmit speech at 16kbps or less. Recent efficiency improvements to the Teams audio codec make it possible to deliver quality sound even as low as 6kbps with minimal audible distortion.
Take audio beyond speech quality with High-fidelity music mode
High-efficiency codecs depend on speech model parameters that can characterize the vocal tract and pitch of the speaker. This does not work well for non-speech signals such as music. As users increasingly share an expanded variety of audio signals including music lessons or songs through other applications it is increasingly important to provide high-fidelity options to transmit audio signals other than speech.
High-fidelity music mode addresses the need to share these types of content in Teams by transmitting audio signals with a 32kHz sampling rate (16kHz bandwidth) at 128kbps, preserving fidelity while reducing the bitrate by 4x compared to lossless encoding.
The optimized experience in Teams applies to signals captured by microphones as well as audio played while sharing an application or desktop. The result is significantly improved audio quality of music and other non-speech signals in Teams calls and meetings.
Microsoft is committed to design a better user experience to improve the quality of your calls and meetings. So, to keep up to date with the new Teams features they release, please stay tuned to our blog or contact us for more information.