Converts Opus files to AAC format — voice-over-IP, real-time communication, and streaming at very low bitrates with excellent quality to modern streaming services, YouTube, and devices where AAC is the native codec. All conversion happens locally in your browser with no file size limits.
Runs on FFmpeg
Content reviewed October 2026 · About Toolzum
Convert OPUS audio files to MP3 format directly in your browser. Audio never leaves your device — conversion and editing run locally in your browser with FFmpeg WASM. Private and free. from VoIP and streaming sources.
Convert AAC audio files to FLAC format directly in your browser. Audio never leaves your device — conversion and editing run locally in your browser with FFmpeg WASM. Private and free.
Convert AAC audio files to M4A format directly in your browser. Audio never leaves your device — conversion and editing run locally in your browser with FFmpeg WASM. Private and free.
Convert MP4/WebM to GIF animations. Videos up to 250MB. Videos never leave your device — compression and conversion run locally in your browser with FFmpeg WASM.
Compress multiple videos with one shared CRF setting (18 high quality, 23 default, 28 smaller, 35 maximum) encoded libx264 medium preset with 128k AAC audio. Studios batch 20 daily uploads at CRF 28 — local FFmpeg WASM, 2 free batches a day.
Opus (Opus Interactive Audio Codec) uses lossy compressed encoding and is best for voice-over-IP, real-time communication, and streaming at very low bitrates with excellent quality. AAC (Advanced Audio Coding) uses lossy compressed encoding and excels at modern streaming services, YouTube, and devices where AAC is the native codec. Converting between them lets you take advantage of each format's strengths — for example, using a compressed format for sharing and a lossless format for editing. All conversion happens locally in your browser with no file size limits.
At the same bitrate, Opus is generally more efficient than AAC. At 256kbps, most listeners cannot tell the difference. For critical listening, keep your Opus originals.
AAC typically needs a slightly higher bitrate than Opus to achieve equivalent quality. A 128kbps Opus file might become a 160-192kbps AAC file of similar perceptual quality.
Standard metadata fields like title, artist, album, and track number transfer from Opus to AAC. Custom or non-standard tags may not survive the conversion.
Yes. AAC is Apple's preferred audio format. The converted file plays natively in Apple Music, GarageBand, and any iOS audio app without additional conversion.
Text to Speech (TTS)
Generate natural-sounding speech from text using your browser's built-in voices. Adjust speed and pitch — download your text as .txt.
Audio Cutter
Trim and cut audio files online — MP3, WAV, M4A, FLAC, and OGG. Set start and end times with sliders, then download the trimmed MP3 clip.
MP3 to WAV
Converts MP3 files to WAV format — universal music playback and sharing across all devices and platforms to professional audio editing, mastering, and archival in DAWs and production software. All conversion happens locally in your browser; files up to 100 MB each.
Speech to Text
Dictate live microphone speech to text in multiple languages through your browser's speech service. Live captions for meetings and notes — free to start, no Toolzum account needed.
MP3 Compressor
Shrink MP3 files by lowering bitrate with quality presets — fit podcasts into feed limits. Cut a 50 MB episode to 15 MB cleanly — local FFmpeg work, unlimited saves.
Apple Music Preview Extractor
Extracts publicly available 30-second audio preview clips from Apple Music by resolving the store URL. Free to start with no signup.