ステップ1: アップロード AMR 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 Opus ファイル
AMR に Opus 変換に関するよくある質問
How do I convert AMR audio to Opus without losing quality?
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Upload the AMR file and the converter chooses the Opus codec and bitrate to match the source. Lossless Opus (WAV / FLAC / ALAC) preserves every sample bit-identically; lossy Opus (MP3 / AAC / OGG / Opus) defaults to 192 kbps which is transparent for most ears.
What bitrate will the resulting Opus file use?
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Default is 192 kbps for lossy Opus; pass-through for lossless Opus. 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 AMR to Opus reduce my audio quality?
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If AMR is lossy and Opus is lossless (e.g. MP3 → WAV), the Opus is no better than the AMR — you cannot recover information already discarded. If AMR is lossless and Opus is lossy, the Opus codec recompresses; at 192 kbps the result is transparent for most content.
Does the AMR to Opus converter keep ID3 / metadata tags?
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Yes — title, artist, album, year, track number, and album art are read from the AMR container and written into the Opus 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 AMR files to Opus?
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Yes — drop a folder of AMR 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 Opus keep the same sample rate as AMR?
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By default yes — 48 kHz AMR 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 AMR to Opus?
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Yes — the loudness-normalize option applies ITU-R BS.1770 / EBU R128 normalization to the Opus, targeting -14 LUFS (streaming standard) or -16 LUFS (podcast standard). Useful when batching tracks mastered at varying levels.
Will my Opus 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 Opus codec optimized for your target hardware.
Is my AMR file private during conversion to Opus?
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Yes — uploaded AMR 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 AMR to Opus 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 AMR → Opus finishes in 6 to 12 minutes. Batch jobs parallelize across workers for further speedups.
Why is the Opus louder or quieter than the AMR 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 Opus levels.
Can I convert AMR downloads from streaming services to Opus?
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If the AMR 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.