Experience high-fidelity audio in Microsoft Teams
Published Jan 24 2022 10:00 AM 22.2K Views
Microsoft

A tenet of our ongoing efforts to improve the audio and video experiences in Microsoft Teams is situational optimization – understanding specific use cases and environments and enabling Teams to perform at its peak in those scenarios. One such scenario is to transmit live or pre-recorded music content during a Teams meeting or call. High-fidelity music mode and automatic music detection are new Teams features that optimize for music, to deliver clear sound at frequencies that extend beyond the normal range for speech.

 

Communication apps are frequently designed for meetings or one-on-one 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, medical signals, and speech.

 

Superior speech quality in 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 16kbs 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, songs through other applications, or medical signals during a virtual appointment with a physician, 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.

 

The following examples contrast music transmitted using the speech codec versus the High-fidelity music mode.

Music experienced in a regular meeting:

 

Music experienced in High-fidelity music mode:

 

Check out the following guide for using High-fidelity music mode to play music in Teams.

 

New automatic music detection prompts Teams users to enable High-fidelity music mode

Machine-learning-based noise suppression has now been enabled by default for most Teams customers. This noise suppression considers any non-speech signal picked up by the microphone as noise which should be suppressed. To avoid unintentionally suppressing music, Teams features new automatic music detection which notifies users whenever music is recognized (see below.) This gives users the choice to enable High-fidelity music mode when music is a desired signal, such as a guitar lesson, or continue suppressing unwanted music, such as ambient sound in a coffee shop.

High fidelity mode.png

 

Detecting music with accuracy involved training a deep neural network with more than 1,000,000 audio clips which contain speech and music. We then evaluated this model with an independent test of 1,000 additional audio clips crowd-sourced from a wide range of contributors. This approach ensured a variety of recording conditions such as different microphones and room acoustics. For music lesson simulation, we asked contributors to play different instruments such as piano, guitar, violin, trumpet, and play different background music from a wide variety of music genres including rock, pop, country, R&B, jazz, classical and others.

 

Since we didn’t want the user notification to appear when no music is present, we had a very strict requirement of 0.1% false positives (i.e., speech or noise is classified as music) and even so, we were still able to detect more than 81% of all music clips in our test set, significantly outperforming all published research in this field. Another important requirement was for this machine learning model to run in the Teams client across devices, to preserve a great user experience for all users. More details on our approach can be found in this research paper. Automatic music detection is expected to be generally available in the coming months.

 

Each day, millions of users across the globe choose Teams to communicate across work, school, and home, with innovative features that enable new customer experiences. Automatic music detection and High-fidelity music mode are examples of how Teams uses machine learning and AI to optimize user experiences in real-time, delivering improved audio and video quality without taxing your organization’s network.

 

Stay tuned to this blog to learn about new Teams features designed to improve the quality of your calls and meetings.

 

24 Comments
Occasional Visitor

Unfortunately, if you record a Teams meeting in high fidelity mode, the recording only captures frequencies up to 8Khz, which is basically telephone quality. Its a shame.

Microsoft

Hello Bruce, thank you for pointing this out. We are actively working on the recording support for high fidelity mode. We will update the community when it is ready. 

Senior Member

Is this feature auto-enabled in Microsoft Teams Rooms? Can you manually force this to be always-on at a registry level for executives who want a better meeting experience without having to click the button for every meeting?

Microsoft

First I would like to clarify that the enabling of music mode controls the send side. The receive side does not need to enable music mode in order to receive music mode. So, if the executive wants to hear music mode, the send will need to enable that. The conference room device will receive music mode codec and able to decode. Whether it will render the high bandwidth will depend on the device. At this time, we do not support conference room send music mode. As for always-on, at this time we do not support that as a public feature. 

Occasional Visitor

How about this HiFi capability on iOS devices?

Microsoft

For iOS, we currently do not support send music mode but we do support receiving music mode. However, due to the fact that devices are currently opened at 16kHz sampling rate, one cannot have the full benefits of music mode from the perspective of wider bandwidth. You do receive a higher bit rate coded speech as well as lower low frequency coverage. So overall, you should perceive better quality on iOS when you receive music mode. 

Occasional Contributor

As noted, we really need meeting recording to have the same full bandwidth/high bitrate audio as the live meeting. I was so excited when HiFi mode was added...and then was crushed when I heard the same old band-limited audio in the recordings.

Microsoft

We definitely understand the disappointment with this lack of support for recording. We are working hard to support this; a solution is coming. Will keep the community updated. 

Occasional Visitor

We tried this feature and it did automatically pop up like mentioned earlier, but there was no musical note icon anywhere, and we couldn't find any way to shut it off, so that participant was stuck in high fidelity broadcast until they left and rejoined.

Version 1.5.00.9163

Microsoft

@bjs_mbaker I am sorry to hear that you are having challenges with this feature. In order to better help you resolve the issue, can you please contact me via email? hongsodoma@microsoft.com

Occasional Visitor

I have the same sound problem.

Microsoft

@NealaTryphena , can you please describe your experience in detail? 

Occasional Visitor

I can't see the music note either in my teamswindow. I get a question when I play music for a while if I want to enable HiFi sound but it would be better to be able to manually put it on or off.

 

Occasional Visitor

Like others here I have enabled high fidelity mode in my device settings, and while attending a meeting that I set up, no musical note button appears in the meeting UI.

What I can do is play music for some amount of time in hopes that music will be detected and interact with the prompt should I notice it in time.

 

I spent some time trying to find a keyboard shortcut to toggle this feature as well, no luck there. Overall, no reliable way to test this feature or turn it off after such a test. Could m365 meeting policies be getting in the way of this?


Win10 Pro 21H2, teams installed locally in appdata with an AAD profile v1.5.00.11163 (64-bit)

 

@hongsod I see you're trying to collaborate on this, let me know if you want any information from me, happy to share details. 

Regular Visitor

I saw a music note button on my Teams meeting window yesterday(May/18/2022 in Japan).
But today(May/19/2022 in Japan), I can't find it anymore, even though I have enabled high fidelity mode in my device settings.
Teams version today is the same as yesterday (v1.5.00.11163 (64-bit) updated in 29/April/2022).
OS version is Win 10 pro 21H1 or 20H2.
The same phenomena has occured to the other colleagues.

And some of my colleagues have had the same issue since around the begining of this May.

 

I hope this issue will be soloved soon.

Microsoft

Thank you for the report @JohanVictor @RWIL_ @Takashi_Yamakawa ! We will investigate and keep you updated.

Microsoft

We have identified and fixed the issue. If you restart your Teams app, you should be able to see the fix. If not, please try sign out and sign back in. Please let us know if you still have issues. We apologize for any inconvenience. @Takashi_Yamakawa @RWIL_ @JohanVictor @NealaTryphena @bjs_mbaker 

Senior Member

I have a question.
How much does the load on the Internet line, such as the amount of communication, change when using this function?

Microsoft

@aki_k2485 , if you are asking about the bitrate, the music mode has a bitrate of 128kbps and the speech mode 36kbps.

Senior Member

@hongsod 
Thank you for information. I understand.

Occasional Visitor

Hi, one important question - does the High fidelity mode support STEREO - Sound? To be received even in Mobile App - Teampartners? Thanks for a reply

Regular Visitor

@hongsod 

I have enabled high fidelity mode in my device settings.
 
However, there is no change in sound quality when I enable or disable it.
 
It was working fine for a while after the problem was fixed on 2022.5.20. However, we have recently been experiencing this symptom. Another terminal is showing the same symptoms. Teams version is 1.5.00.14473.
 
It is not a problem with the microphone, as the standard Windows Voice Recorder records clearly.
 
Is there a problem with high fidelity mode in Teams? I hope it will be fixed.
Occasional Visitor

Hi,

I would also like to know if Teams will be able to handle STEREO soon.

My usecase is a headset on the left and a table-mic on the right input of my stereo soundcard.

I would like to switch between those depending on the ambience noise situation in my home office (Kids etc.).

Zoom seems to mix left&right input to mono which is perfect for my situation - but teams only uses the left input in the App - if I use teams via Edge Browser, it actually uses both left&right and sums them to Mono as Zoom does.

And the really funny thing is that Teams Preview App for Linux also uses both left&right!

So actually only the native Teams App for Windows (and MacOS ans Android and iOS) only use the left input channel - is it planned to unify this (hopefully to taking left&right channel) for all platforms?

 

 

 

Microsoft

Looks like I missed notifications of previous inquiries, I apologize for that. 
@johanneslowienLAWUUN , we will be releasing stereo support very soon. Once stereo is enabled, all Teams clients including Teams mobile clients will be able to receive stereo. I am not familiar with Teamspartners, are you referring to Teams mobile App?
@kinobase , I am sorry that music mode stopped working for you, we will investigate and provide update.
@ChristophAA thank you for the feedback. As I mentioned above, we will be supporting stereo soon. We will also revisit the design choice about stereo to mono conversion for Teams native in the meanwhile. Will keep you updated.  

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