How do I convert Opus audio to M4A without losing quality?
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Upload the Opus file and our converter picks a M4A codec / bitrate combination matched to the source. Lossless target (M4A = WAV / FLAC / ALAC) preserves every sample; lossy target (M4A = MP3 / AAC / OGG / Opus) defaults to 192 kbps which is transparent for most ears.
What bitrate does the M4A file use?
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Default 192 kbps for lossy M4A; pass-through (no bitrate dial) for lossless M4A. Override to 320 kbps for audiophile output, or 96 kbps for voice / podcast where smaller files matter more than fidelity at the extremes.
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 cannot recover information that was already thrown away. If Opus is lossless and M4A is lossy, the M4A codec recompresses; at 192 kbps this is transparent for most content.
Does the Opus to M4A converter keep ID3 / metadata tags?
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Yes — title, artist, album, year, track number, and embedded album art are read from Opus and written into the M4A container where the M4A format supports tags (which all common ones do).
Can I batch convert hundreds of Opus files to M4A?
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Yes — drop a folder of Opus files in and we process them in parallel. Pro has more parallel workers and no per-file size cap, so a 500-file batch finishes in minutes rather than tens of minutes.
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 handles this with a high-quality polyphase resampler.
Can I normalize loudness in the Opus to M4A step?
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Yes — the loudness-normalize option applies ITU-R BS.1770 / EBU R128 normalization to the M4A output, targeting -14 LUFS (streaming standard) or -16 LUFS (podcast standard). Useful when batch-converting tracks with varying mastering levels.
Will the M4A play on my car stereo / iPod / Sonos?
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MP3 plays universally. AAC plays on Apple, most Android, and Sonos. FLAC plays on Sonos and modern Android, less well on older iPods. WAV plays on everything but is huge. The advanced options include device presets for these common targets.
Is my Opus file private during conversion?
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Yes — uploaded Opus files are processed in isolated workers and deleted within minutes. We never play, store, or share audio content. See /privacy/ for the data retention window.
How long does converting a 1-hour Opus to M4A take?
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Same-codec re-mux: 10-30 seconds. Re-encode to a different codec: typically 10-20% of source duration, so a 1-hour Opus -> M4A finishes in 6-12 minutes on the standard pipeline.
Why is the M4A file louder / quieter than the Opus source?
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No automatic gain change happens unless you turn on the normalize option. If you do see a level change, your audio player or media library is probably applying ReplayGain or per-track normalization on playback — not us.
Can I convert Opus 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 cannot process them. Sources from Bandcamp, SoundCloud, and personal recordings convert fine.