ステップ1: アップロード Opus 上記のボタンを使用するか、ドラッグ アンド ドロップでファイルをアップロードします。
ステップ 2: 「変換」ボタンをクリックして変換を開始します。
ステップ3: 変換したファイルをダウンロードする AMR ファイル
Opus に AMR 変換に関するよくある質問
How do I convert Opus audio to AMR without losing quality?
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Upload the Opus file and the converter chooses the AMR codec and bitrate to match the source. Lossless AMR (WAV / FLAC / ALAC) preserves every sample bit-identically; lossy AMR (MP3 / AAC / OGG / Opus) defaults to 192 kbps which is transparent for most ears.
What bitrate will the resulting AMR file use?
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Default is 192 kbps for lossy AMR; pass-through for lossless AMR. Override to 320 kbps for audiophile or 96 kbps for voice / podcast. The choice trades file size against audible fidelity; below 96 kbps lossy artifacts become noticeable on music.
Will going from Opus to AMR reduce my audio quality?
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If Opus is lossy and AMR is lossless (e.g. MP3 → WAV), the AMR is no better than the Opus — you cannot recover information already discarded. If Opus is lossless and AMR is lossy, the AMR codec recompresses; at 192 kbps the result is transparent for most content.
Does the Opus to AMR converter keep ID3 / metadata tags?
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Yes — title, artist, album, year, track number, and album art are read from the Opus container and written into the AMR container where the format supports tags. All common targets (MP3, AAC, FLAC, OGG) handle tags fine; raw WAV does not.
Can I batch convert hundreds of Opus files to AMR?
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Yes — drop a folder of Opus files in and we process them in parallel. Premium 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 AMR keep the same sample rate as Opus?
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By default yes — 48 kHz Opus stays 48 kHz in AMR. 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 Opus to AMR?
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Yes — the loudness-normalize option applies ITU-R BS.1770 / EBU R128 normalization to the AMR, targeting -14 LUFS (streaming standard) or -16 LUFS (podcast standard). Useful when batching tracks mastered at varying levels.
Will my AMR play on car stereo, iPod, and Sonos?
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MP3 plays everywhere. AAC plays on Apple, most Android, and Sonos. FLAC plays on Sonos and Android but not on older iPods. WAV plays on everything but is huge. The advanced device-preset dropdown picks a AMR codec optimized for your target hardware.
Is my Opus file private during conversion to AMR?
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Yes — uploaded Opus files are processed in isolated workers and deleted within minutes. We never play back, store long-term, or share the audio content. The full retention window is in /privacy/.
How long does converting a 1-hour Opus to AMR take?
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Same-codec re-mux: 10 to 30 seconds. Re-encode to a different codec: typically 10 to 20% of source duration, so a 1-hour Opus → AMR finishes in 6 to 12 minutes. Batch jobs parallelize across workers for further speedups.
Why is the AMR louder or quieter than the Opus source?
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No automatic gain change happens unless you enable the normalize option. If you observe a level change, your audio player or media library is likely applying ReplayGain or per-track normalization on playback — not us. Disable that to hear the true AMR levels.
Can I convert Opus downloads from streaming services to AMR?
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If the Opus download is unprotected (no DRM), yes. DRM-encrypted streams (Spotify, Apple Music tracks) are encrypted at the bit level and we cannot process them. Bandcamp, SoundCloud downloads, personal recordings, and podcast files convert cleanly.