AudioProcessInfo

Info

AudioProcessInfo represents a process that has an active audio session on the system. Returned by getPlayingProcesses, it provides the process ID, name, session state, and display name. Use it to discover which applications are currently producing audio.

Properties

Property	Type	Description
processId	number	Windows process ID (PID). Pass this to start to begin analyzing this process's audio.
processName	string | null	Process name without the .exe extension (e.g. "Spotify"). May be null if the process name cannot be resolved.
state	'active' | 'inactive' | 'expired' | 'unknown'	Current audio session state. 'active' means the process is actively playing audio.
displayName	string | null	Human-readable display name of the audio session (e.g. "Spotify Premium"). May be null if the session does not provide a display name.

Note

The state field reflects the WASAPI audio session state: 'active' means audio is currently playing, 'inactive' means the session exists but is paused, 'expired' means the session has ended, and 'unknown' indicates an unrecognized state.

Usage

AudioProcessInfo objects are returned by getPlayingProcesses. Use them to:

• Build a UI list of apps currently playing audio
• Let the user select a process to analyze
• Automatically detect and attach to the active audio source

Tips

Filter for state === 'active' to show only processes that are currently producing audio. Use getPlayingProcesses(true) (the default) for the same result without post-processing.

Example

TypeScript

import { getPlayingProcesses, AudioProcessInfo } from '@eisland/windows-volume-analyzer';

// Get all processes with audio sessions
const processes: AudioProcessInfo[] = getPlayingProcesses(false);

for (const proc of processes) {
  const label = proc.displayName ?? proc.processName ?? `PID ${proc.processId}`;
  console.log(`${label} [${proc.state}] (PID: ${proc.processId})`);
}

// Find the first actively playing process
const active: AudioProcessInfo | undefined = processes.find((p) => p.state === 'active');
if (active) {
  console.log(`Now playing: ${active.displayName ?? active.processName}`);
}

JavaScript

const { getPlayingProcesses } = require('@eisland/windows-volume-analyzer');

// Get all processes with audio sessions
const processes = getPlayingProcesses(false);

for (const proc of processes) {
  const label = proc.displayName ?? proc.processName ?? `PID ${proc.processId}`;
  console.log(`${label} [${proc.state}] (PID: ${proc.processId})`);
}

// Find the first actively playing process
const active = processes.find((p) => p.state === 'active');
if (active) {
  console.log(`Now playing: ${active.displayName ?? active.processName}`);
}

Notes

Note

The processId is the Windows PID and is unique for the lifetime of the process. However, PIDs can be reused after a process exits. Always re-query getPlayingProcesses if significant time has passed before starting analysis.

Tips

Use displayName for user-facing labels — it is typically more descriptive than processName. Fall back to processName when displayName is null.

Important

The list returned by getPlayingProcesses is a snapshot at the time of the call. Processes may start or stop audio sessions between queries. For real-time tracking, poll the function periodically.

Danger Avoidance

Caution

Do not cache processId values indefinitely. If the target process exits and a new process reuses the same PID, starting analysis on the stale PID will capture the wrong process's audio. Always re-query getPlayingProcesses before starting a new analysis session.