Sources, caching and cancellation

Sources

Every function that reads audio accepts an AudioSource:

await analyzeAudio('/data/user/0/app/files/note.wav');                     // absolute path
await analyzeAudio('file:///var/mobile/…/voice-note.wav');                 // file:// URI
await analyzeAudio('https://example.com/song.mp3');                        // downloaded and cached
await analyzeAudio({ uri: 'https://api.example.com/a/1', headers: { Authorization: token } });
await analyzeAudio(arrayBufferWithEncodedAudio);                           // in memory

Other URI schemes (content://, asset://, …) are rejected; copy such files to a path first.

Downloads

analyzeAudio, getAudioInfo and useWaveform download http(s):// sources with load, which you can also call yourself:

• Files are cached by their full URL, query string included, in Caches/react-native-audio-analyzer/ (iOS) and cacheDir/react-native-audio-analyzer/ (Android). Headers are not part of the cache key.
• A cached file is returned immediately and works offline. The operating system may evict it when storage runs low.
• Content at the same URL is not re-validated; put a version in the URL if a file can change.
• Concurrent calls for the same URL and headers share one download. Redirects are followed, including between http and https; headers are only sent to the origin you requested, never to another host, port or scheme a redirect points to.
• Non-2xx responses reject and are never cached. An interrupted download never leaves a broken file behind.

clearCache deletes the downloaded files; getCacheSize returns their size in bytes. Both include files left behind by v3 (<md5>.audio in the cache or temporary directory), which v4 never reads, so one clearCache() after upgrading frees them.

Cancellation

const controller = new AbortController();
const peaks = analyzeAudio(url, { signal: controller.signal });
controller.abort(); // rejects with an AbortError

useWaveform cancels automatically when the source or analysis options change and when the component unmounts. A download in progress is not interrupted: it finishes in the background and is cached for the next call.

Cache the analysis

Peaks is plain data. Serialize it to skip decoding on the next launch, or compute it on a server and ship the result:

import { decodePeaks, encodePeaks } from 'react-native-audio-analyzer';

const bytes = encodePeaks(peaks);   // ArrayBuffer
const restored = decodePeaks(bytes);

bits	Bytes per bucket and channel	Max error
8 (default)	3	≈ 0.008 near full scale, less for quiet values
16	6	≈ 0.00002
32	12	lossless

The format is versioned and forward compatible: newer writers may add header fields and metrics that older readers skip.