Step 1: Submit your Opus files using the button above or by pull and release.
Step 2: Click the 'Transform' button to start the transformation.
Step 3: Save your converted M4A files.
Opus to M4A Transformation FAQ
What bitrate does the M4A file use?
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A lossy M4A 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 M4A (WAV, FLAC) ignores the bitrate and keeps every sample.
Will going from Opus to M4A reduce my audio quality?
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If Opus is lossy and M4A is lossless (e.g. MP3 → WAV), the M4A file is no better than the Opus — you can't recover information that's already been thrown away. If Opus is lossless and M4A is lossy, expect the M4A codec to recompress; at 192 kbps this is transparent for most content.
Can I batch convert hundreds of Opus files to M4A?
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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 M4A keep the same sample rate as Opus?
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By default yes (48 kHz Opus → 48 kHz M4A). If you need to downsample for compatibility (e.g. 96 kHz → 44.1 kHz for CD burning) the advanced sample-rate option does this with high-quality resampling.
Can I normalize loudness in the Opus to M4A step?
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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 M4A through a Normalize tool on this site.
Will the M4A play on my car stereo / iPod / 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.
Is my Opus file private during conversion?
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Yes. Uploaded Opus files are processed on our own conversion servers, no person reviews them, and they are never shared. The upload and the converted M4A 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 Opus to M4A 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.
Why is the M4A file louder / quieter than the Opus source?
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The converter does not change the level: it has no gain or normalize setting. If you hear a difference, your player or media library is probably applying ReplayGain or its own volume levelling on playback; switch that off to hear the M4A as it is.
Can I convert Opus streaming downloads to M4A?
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If the Opus download is unprotected (no DRM), yes. DRM-encrypted streaming files (Spotify, Apple Music) are encrypted at the bit level and we can't process them. Sources from Bandcamp, SoundCloud download, and personal recordings convert fine.
