WebRTC Metrics

A comprehensive overview of WebRTC statistics, derived indicators, and observable signals, to better understand call quality, connectivity, and user experience in rtcStats

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media-sourceoutboundaudio

audioLevel

The audio level of the media source.

Description

Real number

MUST NOT exist for video (this is audio only).

Represents the audio level of the media source.

The value is between 0..1 (linear), where 1.0 represents 0 dBov, 0 represents silence, and 0.5 represents approximately 6 dBSPL change in the sound pressure level from 0 dBov.

The audioLevel is averaged over some small interval, using the algorithm described under totalAudioEnergy. The interval used is implementation-defined.

Interpreting Values

Range	Description
0	Silence. Mic is muted or no input detected
0.001-0.01	Very quiet. Possible causes: quiet environment, mic far away, low gain
0.01-0.1	Typical speech range
0.1-0.5	Loud speech
>0.5	Very loud. Risk of clipping and distortion

Common Causes

Causes of problematic values:

Muted microphone
Wrong input device selected
OS permissions blocking mic access
Mic gain set too low or too high
Hardware issue (broken mic, loose connection)
Noise gate too aggressive

User Experience Impact

This is the local mic level BEFORE encoding and sending. If this is 0, remote participants hear nothing regardless of network quality
If too high, remote participants hear distorted audio
Fluctuating levels between 0 and normal values may indicate an intermittent hardware or permissions issue

Troubleshooting

If 0 - check mic permissions, selected device, and mute state.
If very low - increase system mic volume or move closer to the microphone.
If very high - decrease mic gain to avoid clipping.
Compare with inbound-rtp.audioLevel on the remote side to verify audio is reaching them.