Introduction

The Agora RTC SDK enables you to manage the volume of the recorded audio or of the audio playback according to your actual scenario. For example, to mute a remote user in a one-to-one call, you can set the audio playback volume as 0.

This article provides the APIs and additional information relating to audio recording, audio mixing, and audio playback volume settings.

Sample project

We provide an open-source JoinChannelAudio.swift sample project that implements adjusting the recording and playback on GitHub. You can download the sample project and view the source code.

Implementation

Before adjusting the audio volume, ensure that you have implemented the basic real-time communication functions in your project. For details, see Start a Call or Start Live Interactive Streaming.

Adjust the recording volume

Recording is the process of sampling audio by a recording device and transmitting the recorded signal to the sender. To adjust the recording volume, you can set the volume of the recording device or set the volume of the recorded signal. We recommend using audio device-related APIs to adjust the recording volume.

Set the volume of the recording device

Call setDeviceVolume to set the volume of your recording device.

The volume parameter represents the audio level of your recording device, ranging between 0 and 255:

• 0: Mute.
• 255: The maximum volume of the device.

As the following screenshot shows, the volume value corresponds to the audio level for your audio recording device.

Sample code

// swift
// Sets the volume of your recording device as 50.
agoraKit.setDeviceVolume(.audioRecording, volume: 50)

// objective-c
//  Sets the volume of your recording device as 50.
[agoraKit setDeviceVolume: AgoraMediaDeviceTypeAudioRecording volume: 50];

Set the volume of the recorded signal

If setDeviceVolume does not suffice, you can call adjustRecordingSignalVolume to set the volume of the recorded signal.

The volume parameter represents the audio level of the recorded signal, ranging between 0 and 400:

• 0: Mute.
• 100: (Default) The original volume.
• 400: Four times the original volume (amplifying the audio signals by four times).

Sample code

// Swift
// Sets the volume of the recorded signal as 50.
agoraKit.adjustRecordingSignalVolume(50)

// Objective-C
// Sets the volume of the recorded signal as 50.
[agoraKit adjustRecordingSignalVolume: 50];

API reference

• setDeviceVolume
• adjustRecordingSignalVolume

Adjust the playback volume

Playback is the process of playing the received audio signal on the local playback device. To adjust the playback volume, you can set the volume of the playback device, or set the volume of the audio signal.

Set the volume of the playback device

To set the volume on the playback device directly, call setDeviceVolume.

The volume parameter represents the audio level of your playback device, ranging between 0 and 255:

• 0: Mute.
• 255: The maximum volume of the device.

As the following screenshot shows, the volume value corresponds to the audio level for your audio playback device.

Sample code

// Swift
// Sets the volume of the playback device as 50.
agoraKit.setDeviceVolume(.audioPlayout, volume: 50)

// Objective-C
// Sets the volume of the playback device as 50.
[agoraKit setDeviceVolume: AgoraMediaDeviceTypeAudioPlayout volume: 50];

Set the volume of the playback signal

If setDeviceVolume does not suffice, you can use adjustPlaybackSignalVolume or adjustUserPlaybackSignalVolume to set the volume of the audio signal.

• adjustPlaybackSignalVolume：
  • Universally sets the playback audio level of all remote users after audio mixing.
  • The volume parameter represents the playback audio level, ranging between 0 and 400.
• adjustUserPlaybackSignalVolume：
  • Adjusts the playback audio level of a specified remote user after audio mixing. Call this method as many times as necessary to adjust the playback volume of different remote users, or to repeatedly adjust the playback volume of the same remote user.
  • The volume parameter represents the playback audio level, ranging between 0 and 100.

Sample code

// Swift
// Sets the volume of the local playback of all remote users as 50.
agoraKit.adjustPlaybackSignalVolume(50)
// Sets the volume of the local playback of a specified remote user as 50.
agoraKit.adjustUserPlaybackSignalVolume(uid, volume: 50)

// Objective-C
// Sets the volume of the local playback of all remote users as 50.
[agoraKit adjustPlaybackSignalVolume: 50];
// Sets the volume of the local playback of a specified remote user as 50.
[agoraKit adjustUserPlaybackSignalVolume: uid, volume: 50];

API reference

• setDeviceVolume
• adjustPlaybackSignalVolume
• adjustUserPlaybackSignalVolume
• adjustAudioMixingPlayoutVolume

Get the data of the loudest speaker (callback)

When recording, mixing, or playing audio, you can use the following methods to get the data of the loudest speaker in the channel.

• Reports users with the highest peak volumes. The reportAudioVolumeIndicationOfSpeakers reports the user IDs the corresponding volumes of the currently loudest speakers in the channel.

  You must call enableAudioVolumeIndication to be able to receive this callback.

Sample code

// Swift
// Gets the user IDs of the users with the highest peak volume, the corresponding volumes, as well as whether the local user is speaking.
// @param speakers is an array containing the user IDs and volumes of the local and the remote users. The volume parameter ranges between 0 and 255.
// @param totalVolume refers to the total volume after audio mixing, ranging between 0 and 255.
func rtcEngine(_ engine: AgoraRtcEngineKit, reportAudioVolumeIndicationOfSpeakers speakers:
[AgoraRtcAudioVolumeInfo], totalVolume: Int) {
}

// Objective-C
// Gets the user IDs of the users with the highest peak volume, the corresponding volumes, as well as whether the local user is speaking.
// @param speakers is an array containing the user IDs and volumes of the local and the remote users. The volume parameter ranges between 0 and 255.
// @param totalVolume refers to the total volume after audio mixing, ranging between 0 and 255.
- (void)rtcEngine:(AgoraRtcEngineKit *_Nonnull)engine reportAudioVolumeIndicationOfSpeakers:(NSArray<AgoraRtcAudioVolumeInfo*> *_Nonnull)speakers totalVolume:(NSInteger)totalVolume {
}

• Reports the user with the highest average volume. The activeSpeaker callback reports the user ID with the highest average volume during a certain period of time.

  You must call enableAudioVolumeIndication to be able to receive this callback.

Sample code

// Swift
// Gets the user ID of the user with the highest average volume during a certain period of time. A uid of 0 indicates the local user.
func rtcEngine(_ engine: AgoraRtcEngineKit, activeSpeaker speakerUid: UInt) {
}

// Objective-C
// Gets the user ID of the user with the highest average volume during a certain period of time. A uid of 0 indicates the local user.
- (void)rtcEngine:(AgoraRtcEngineKit *_Nonnull)engine activeSpeaker:(NSUInteger)speakerUid {
}

API reference

• reportAudioVolumeIndicationOfSpeakers
• activeSpeaker

Considerations

Setting the audio level too high may cause audio distortion on some devices.

Reference

When adjusting the audio volume, you can also refer to the following articles:

• If you need to adjust the volume of audio effect or audio mixing files, refer to Play Audio Files.
• How to solve the problem of low volume?