# Manage media and devices (/en/realtime-media/rtc/build/control-audio-and-devices/volume-control-and-mute/ios)

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This page shows you how to configure volume settings for audio recording, audio playback, and for the playback of music files.

## Understand the tech

Agora RTC SDK supports adjusting the audio volume for both recording and playback to meet practical application use-cases. For example, during a two-person call, you can mute a remote user by adjusting the playback volume setting to 0.

      
  
      
The figure below shows the workflow of adjusting the volume.

<Accordions>
  <Accordion title="Volume adjust workflow">
    ![VolumeControlMute](https://assets-docs.agora.io/images/video-sdk/volume-control-mute-adjustVolume.svg)
  </Accordion>
</Accordions>

**Playback** refers to transmitting an audio signal from a sender to a recipient, where it is played back through a playback device.

**In-ear monitoring** refers to the process of playing audio captured by a device.

**Recording** refers to the process in which audio signals are captured by a recording device and then sent to the transmitter.

<CalloutContainer type="warning">
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    Caution
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  <CalloutDescription>
    If you set the volume too high using the signal volume adjustment methods, it may lead to audio distortion on some devices.
  </CalloutDescription>
</CalloutContainer>

    
  
      
  
      
  
      
  
      
  
      
  
      
  
      
  
      
  
## Prerequisites

Ensure that you have implemented the [SDK quickstart](/en/realtime-media/rtc/get-started-sdk) in your project.

## Implement volume control

      
  
      
  
      
  
      
Use one or more of the following volume control methods to adjust volume settings.

### Mute and unmute users

* To mute or unmute the local audio stream, call `muteLocalAudioStream`:

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    ```objc
    [agoraKit muteLocalAudioStream:YES];
    ```
  </CodeBlockTab>

  <CodeBlockTab value="swift">
    ```swift
    // Stop publishing the local audio stream
    agoraKit.muteLocalAudioStream(true)

    // Resume publishing the local audio stream
    agoraKit.muteLocalAudioStream(false)
    ```
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* To mute or unmute a remote user, call `muteRemoteAudioStream` with the `uid` of the remote user:

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    ```objc
    [agoraKit muteRemoteAudioStream:remoteUid mute:YES];
    ```
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    ```swift
    // Stop subscribing to the audio stream of the remote user
    agoraKit.muteRemoteAudioStream(remoteUid, mute: true)

    // Resume subscribing to the audio stream of the remote user
    agoraKit.muteRemoteAudioStream(remoteUid, mute: false)
    ```
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<CalloutContainer type="info">
  <CalloutDescription>
    To mute remote users without unsubscribing, set their [playback volume](#adjust-the-playback-volume) to `0`.
  </CalloutDescription>
</CalloutContainer>

### Adjust the playback volume

Call `adjustPlaybackSignalVolume` or `adjustUserPlaybackSignalVolume` to adjust the volume of the audio playback signal.

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    ```objc
    // Set the volume of all remote users played locally
    [agoraKit adjustPlaybackSignalVolume: 50];
    // Set the local playback volume for a specific remote user.
    [agoraKit adjustUserPlaybackSignalVolume: uid, volume: 50];
    ```
  </CodeBlockTab>

  <CodeBlockTab value="swift">
    ```swift
    // Set the volume of all remote users played locally
    agoraKit.adjustPlaybackSignalVolume(50)
    // Set the local playback volume for a specific remote user
    agoraKit.adjustUserPlaybackSignalVolume(uid, volume: 50)
    ```
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### Adjust the in-ear monitoring volume

During the process of audio capture, mixing, and playback, Agora enables you to adjust the volume of in-ear monitoring. Enable and set the in-ear monitoring through `enableInEarMonitoring` and `setInEarMonitoringVolume`.

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    ```objc
    // Enable in-ear monitoring
    [agoraKit enableInEarMonitoring:true];
    // Adjust in-ear monitoring volume
    [agoraKit setInEarMonitoringVolume:50];
    ```
  </CodeBlockTab>

  <CodeBlockTab value="swift">
    ```swift
    // Enable in-ear monitoring
    agoraKit.enableInEarMonitoring(true)
    // Adjust in-ear monitoring volume
    agoraKit.setInEarMonitoringVolume(50)
    ```
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### Adjust the recording volume

Call `adjustRecordingSignalVolume` to adjust the volume of the audio recording signal.

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    ```objc
    // Adjust the recording signal volume
    [agoraKit adjustRecordingSignalVolume: 50];
    ```
  </CodeBlockTab>

  <CodeBlockTab value="swift">
    ```swift
    // Adjust the recording signal volume
    agoraKit.adjustRecordingSignalVolume(50)
    ```
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When configuring audio settings, it's essential to understand the default behavior and the options available. Here are the key points to keep in mind:

* The SDK defaults to a device volume of `85` when using the recording device to capture audio signals.
* A volume of `0` means mute, and a volume of `255` represents the maximum volume of the device.
* If the SDK detects that the recording volume is too low in the current environment, it automatically increases the volume of the recording device.
* The volume of the recording device directly influences the global volume of the device.
* If the default recording device volume does not meet your requirements, adjust it by regulating the signal amplitude captured by the microphone or sound card.

### Get volume information of users

RTC SDK enables you to obtain the user IDs and corresponding volumes of the three users with the highest instantaneous volumes in a channel during the process of audio recording, mixing, and playback. You use `reportAudioVolumeIndicationOfSpeakers` callback to obtain this information. A returned `uid` of `0` in the callback indicates the local user.

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    Call `enableAudioVolumeIndication` to enable reporting of the users' volume in the callback.
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</CalloutContainer>

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    ```objc
    // Retrieve the user IDs of the three users with the highest instantaneous speaking volume,
    // their respective volumes, and determine whether the local user is speaking.
    - (void)rtcEngine:(AgoraRtcEngineKit *_Nonnull)engine
    reportAudioVolumeIndicationOfSpeakers:(NSArray<AgoraRtcAudioVolumeInfo *> *_Nonnull)speakers
                                  totalVolume:(NSInteger)totalVolume {
    }
    ```
  </CodeBlockTab>

  <CodeBlockTab value="swift">
    ```swift
    // Retrieve the user IDs of the three users with the highest instantaneous speaking volume,
    // their respective volumes, and determine whether the local user is speaking.
    func rtcEngine(
        _ engine: AgoraRtcEngineKit,
        reportAudioVolumeIndicationOfSpeakers speakers: [AgoraRtcAudioVolumeInfo],
        totalVolume: Int
    ) {
    }

    // Enable the reportAudioVolumeIndicationOfSpeakers callback
    agoraKit.enableAudioVolumeIndication(200, smooth: 3, reportVad: true)
    ```
  </CodeBlockTab>
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## Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

      
  
      
  
      
  
      
### API reference

* [`adjustRecordingSignalVolume`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agorartcenginekit/adjustrecordingsignalvolume%28_:%29)
* [`adjustPlaybackSignalVolume`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agorartcenginekit/adjustplaybacksignalvolume%28_:%29)
* [`adjustUserPlaybackSignalVolume`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agorartcenginekit/adjustuserplaybacksignalvolumeex%28_\:volume\:connection:%29)
* [`adjustAudioMixingPlayoutVolume`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agorartcenginekit/adjustaudiomixingplayoutvolume%28_:%29)
* [`enableInEarMonitoring`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agorartcenginekit/enable%28inearmonitoring\:includeaudiofilters:%29)
* [`setInEarMonitoringVolume`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agorartcenginekit/setinearmonitoringvolume%28_:%29)
* [`enableaudiovolumeindication`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agorartcenginekit/enableaudiovolumeindication%28_\:smooth\:reportvad:%29)
* [`muteLocalAudioStream`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agoraspatialaudiokitbase/mutelocalaudiostream%28_:%29)
* [`muteRemoteAudioStream`](https://api-ref.agora.io/en/video-sdk/ios/4.x/documentation/agorartckit/agorartcenginekit/muteremoteaudiostream%28_\:mute:%29)

### Sample projects

Agora offers the following open-source sample project for adjusting recording, playback, and in-ear monitoring volumes for your reference:

* GitHub: [JoinChannelAudio](https://github.com/AgoraIO/API-Examples/tree/main/iOS/APIExample/APIExample/Examples/Basic/JoinChannelAudio)

For adjusting the playback volume of mixing or audio effect files, refer to the following sample project:

* GitHub: [AudioMixing](https://github.com/AgoraIO/API-Examples/tree/main/iOS/APIExample/APIExample/Examples/Advanced/AudioMixing)

### Frequently asked questions

* [How can I solve the problem of low volume?](/en/api-reference/faq/quality/audio_low)

    
  
      
  
      
  
      
  
      
  
      
  
      
  
      
  
      
  
### See also

* [Custom audio source](/en/realtime-media/rtc/build/customize-audio-processing/custom-audio)
* [Custom video source](/en/realtime-media/rtc/build/capture-and-render-video/custom-video)