WASM Audio Decoder - Online Play FLAC/Opus Locally

WASM (WebAssembly) audio decoding runs native-performance audio codecs directly in your browser. Instead of uploading files to a server for conversion, the decoding happens entirely on your device using compiled C/C++ libraries like libFLAC and libopus. This ensures privacy, speed, and offline capability — no data ever leaves your computer.

FLAC (Free Lossless Audio Codec) is a lossless format — it preserves every bit of the original audio, making it ideal for archiving and high-fidelity music. File sizes are larger but quality is identical to the source (typically 16-bit or 24-bit, up to 384kHz).

Opus is a modern lossy codec optimized for both speech and music, offering exceptional quality at low bitrates (8–510 kbps). It's the default codec for VoIP, streaming, and WebRTC. Opus files are much smaller than FLAC but discard some audio data perceptually. It supports 8kHz to 48kHz sample rates.

Absolutely safe. All processing happens 100% locally in your browser using WebAssembly. Your audio files are never uploaded to any server. The file stays on your device, is decoded in memory, and played directly through your browser's audio system. You can even disconnect from the internet after the page loads — the tool works fully offline.

All modern browsers with WebAssembly and Web Audio API support: Chrome 57+, Firefox 52+, Safari 11+, Edge 79+, and Opera 44+. Mobile browsers including iOS Safari 11+ and Chrome for Android are also fully supported. The tool automatically detects compatibility and will notify you if your browser lacks required features.

There's no hard-coded limit, but practical constraints depend on your device's available RAM. Typically, files up to 200–400 MB decode smoothly on modern devices with 8GB+ RAM. For very large FLAC files (1GB+), the browser may slow down or run out of memory. We recommend splitting extremely large audio files before decoding. Opus files are generally much smaller and rarely cause issues.

Key advantages over online converters:
• Privacy: No file upload — data stays local
• Speed: No network transfer time for large files
• No limits: No daily conversion quotas or paywalls
• Offline: Works without internet after initial page load
• Quality: Lossless FLAC decoding with bit-perfect output
• Free: No subscriptions, no ads, no registration

Yes! Once decoding is complete, click the WAV button to download the decoded audio as a standard WAV file (16-bit PCM, 44.1kHz or original sample rate). This is useful for further editing in DAWs like Ableton, Audacity, or Logic Pro. For FLAC files, the WAV export preserves the full lossless quality. For Opus files, the WAV contains the decoded PCM representation of the lossy source.

On first use, your browser downloads the WebAssembly binary (~200–400KB) and compiles it. This one-time initialization takes 1–3 seconds depending on your connection and device. Subsequent decodes are much faster because the WASM module is cached. The decoding engine itself is highly optimized — a 50MB FLAC file typically decodes in under 2 seconds on modern hardware.