Step 1: Share your AAC files using the button above or by drag and drop.
Step 2: Click the 'Transform' button to start the transformation.
Step 3: Grab your converted Opus files.
AAC to Opus Transformation FAQ
What bitrate will the resulting Opus file use?
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A lossy Opus is encoded at 192 kbps by default. The Audio Quality setting also offers 320 kbps for the best quality and 128 kbps for a smaller file. A lossless Opus (WAV, FLAC) ignores the bitrate and keeps every sample.
Is converting AAC to Opus a second round of lossy compression?
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Yes, and it is worth planning around. Both formats are lossy, so the Opus encoder is working from audio that has already been through one psychoacoustic pass, and its own decisions compound the first set. At 192 kbps or above the result is still transparent for most listening. If you have a lossless master anywhere, encoding the Opus from that instead avoids the double pass entirely. AAC is lossy but more efficient than MP3, and it handles up to 48 channels natively rather than being bolted onto a stereo design. Opus scales from 6 kbps mono speech to 510 kbps stereo music in the same bitstream and switches modes automatically.
Will the Opus play in my car or on older hardware?
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Often not. AAC is decoded by essentially everything, including car head units and elderly players; Opus needs software that knows the codec, which standalone hardware frequently does not have. If the destination is a car stereo or a portable player, that is a strong argument for staying on AAC. Opus is almost never supported by standalone hardware — assume software playback only, and expect car stereos to ignore it.
Will going from AAC to Opus reduce my audio quality?
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If AAC is lossy and Opus is lossless (e.g. MP3 → WAV), the Opus is no better than the AAC — you cannot recover information already discarded. If AAC is lossless and Opus is lossy, the Opus codec recompresses; at 192 kbps the result is transparent for most content.
Can I batch convert hundreds of AAC files to Opus?
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Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
Will the Opus keep the same sample rate as AAC?
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By default yes — 48 kHz AAC stays 48 kHz in Opus. If you need to downsample for compatibility (96 kHz → 44.1 kHz for CD burning), the sample-rate option applies high-quality resampling in the same encode pass.
Can I normalize loudness when converting AAC to Opus?
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Not in this step. The converter has no loudness setting and leaves the level as it is. To even out the volume, run the finished Opus through a Normalize tool on this site.
Will my Opus play on car stereo, iPod, and Sonos?
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MP3 plays almost everywhere. AAC plays on Apple devices, most Android phones and Sonos. FLAC plays on Sonos and Android but not on older iPods, and WAV plays on nearly everything but makes large files. There are no device presets on this page, so choose the target format your player supports. Opus is the best-sounding lossy codec at low bitrates by a clear margin, and it powers WhatsApp voice notes, Discord and WebRTC.
Is my AAC file private during conversion to Opus?
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Yes. Uploaded AAC files are processed on our own conversion servers, no person reviews them, and they are never shared. The upload and the converted Opus are both deleted automatically about 24 hours after the conversion, which leaves time to download the result. See /privacy/ for the full policy.
How long does converting a 1-hour AAC to Opus take?
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It depends on the size and length of the file. Small documents and images are usually ready quickly. Long videos take the longest, because most video conversions re-encode every frame.
