Expo AV audio not playing on iOS/ iPhone

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06-10-2024

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The Silent Show: Troubleshooting Expo AV Audio on iOS

Ever created a cool Expo app that boasts awesome audio features, only to find they're mysteriously mute on iOS? It's a common frustration, but fear not! This article breaks down the culprit behind this audio silence and provides solutions to get your sound flowing.

The Problem:

Expo's expo-av package, designed for media playback, occasionally stumbles on iOS devices. This can manifest as your audio files refusing to play, leading to a frustratingly silent experience.

Scenario:

Imagine you've built a fantastic Expo app with an audio guide feature. You've carefully implemented expo-av to play audio files, and it works flawlessly on Android. But, when you test on your iPhone, silence greets you.

Code Snippet:

import { Audio } from 'expo-av';

const playAudio = async () => {
  const soundObject = new Audio.Sound();
  try {
    await soundObject.loadAsync(require('./audio.mp3'));
    await soundObject.playAsync();
  } catch (error) {
    console.error('Error playing audio:', error);
  }
};

The Culprit:

The culprit often lies within iOS's stringent background audio restrictions. By default, iOS prohibits background audio playback unless you've explicitly requested permission.

Unveiling the Solution:

Here's how to regain your audio's voice:

1. Permission is Key:

   • Add the NSBackgroundModes key to your Info.plist file in your Expo project.
   • Under this key, add the value audio to indicate your app requires background audio capabilities.

2. The AVAudioSession Power:

   • iOS utilizes the AVAudioSession object to manage audio behavior.
   • Use expo-av's Audio.setAudioModeAsync method to configure this session:

   import { Audio } from 'expo-av';
   
   const setupAudioSession = async () => {
     try {
       await Audio.setAudioModeAsync({
         allowsRecordingIOS: false,
         interruptionModeIOS: Audio.INTERRUPTION_MODE_IOS_DO_NOT_MIX,
         playsInSilentModeIOS: true,
         shouldDuckAndroid: true,
         staysActiveInBackground: true, 
       });
     } catch (error) {
       console.error('Error setting audio mode:', error);
     }
   };
   
   setupAudioSession();
   

   • This code ensures your audio continues playing even when your app goes to the background.

3. Info.plist Enhancement:

   • For iOS 10 and above, include the UIBackgroundModes key with audio as its value in your Info.plist. This explicitly signals your app's intent to play audio in the background.

Additional Considerations:

• Audio Focus: iOS prioritizes system sounds and calls, so be mindful of audio focus. Use Audio.setAudioModeAsync to control your app's audio behavior when interruptions occur.
• Background Audio Limits: Be aware of iOS's limitations for background audio playback. Long-duration audio playback might require special handling to prevent your app from being terminated.

Resources:

• expo-av Documentation: https://docs.expo.dev/versions/latest/sdk/audio/
• Apple's Audio Session Guide: https://developer.apple.com/documentation/avfoundation/avaudiosession

Conclusion:

By understanding iOS audio restrictions and leveraging expo-av's capabilities, you can conquer the challenge of silent audio on your iPhone. Remember to request the necessary permissions, configure the AVAudioSession, and navigate background audio limitations. Armed with this knowledge, your Expo app can finally unleash its audio potential!