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AMR → AAC
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Fast, secure AMR to AAC conversion. No registration required.
Here is the short version — AMR is the narrowband speech codec built for mobile voice recordings and 3G calls. Hence the need for AAC. Need a AAC version of a AMR recording for a podcast host, audio book platform or DAW that refuses the original container? Drop the file above and our encoder produces a clean AAC you can drag straight into the destination tool. Metadata such as title, artist and cover art travels with the audio. Technical note: AMR is the narrowband speech codec built for mobile voice recordings and 3G calls. Compare that with AAC is the Advanced Audio Codec, more efficient than MP3 and ubiquitous in modern streaming.
AMR Audio
Source formatAMR (Adaptive Multi-Rate) is an audio format optimized for speech, used in phone calls.
AAC Audio
Target formatAAC is a lossy audio codec that delivers better sound quality than MP3 at similar bitrates. It is the default audio format for Apple Music, YouTube, and most streaming services.
Why convert AMR to AAC
AMR Audio is great in its own niche, but AAC Audio is either more universally playable or better suited to the device you are targeting. Converting lets you ship the audio without asking listeners to install a codec. The loss in quality between the two is negligible at sensible bitrates.
HOW TO CONVERT
AMR → AAC
Upload the AMR
Drop or select your AMR file. The upload is encrypted and the file is queued for conversion.
Transcode via FFmpeg
FFmpeg decodes the AMR stream to PCM internally, then re-encodes as AAC at the bitrate you select.
Download the AAC
The AAC is delivered as a direct download; metadata and cover art transfer automatically where possible.
Common Use Cases
Share across platforms
Send AAC files to anyone without worrying about whether they have the right software for AMR.
Embed in documents
Drop AAC output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
AAC often produces smaller files than AMR for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
AMR vs AAC — Strengths and limitations
What each format does best, and where it falls short.
AMR Strengths
- Extremely low bitrate — 4.75-12.2 kbps for speech.
- Designed for error-prone mobile channels — handles packet loss gracefully.
- Tiny file sizes — hours of voice in a few MB.
- Mandatory codec in all 3G/UMTS phones — universal cellular compatibility.
Limitations
- Speech-only — music sounds distorted.
- Narrowband (8 kHz sample rate) — muffled compared to modern codecs.
- Patent-encumbered until recently — licensing fees slowed adoption outside telephony.
AAC Strengths
- Better quality than MP3 at equal bitrate — the industry standard since 2000s.
- Universally supported on every smartphone, OS, and browser.
- Efficient on battery thanks to widespread hardware decoding.
- Scales from 8 kbps speech (HE-AACv2) to lossy-transparent 320 kbps.
- Five-channel + LFE surround support out of the box.
Limitations
- Patent-encumbered — encoders have licensing fees, which is why open alternatives (Opus, Vorbis) exist.
- Slightly more complex to encode than MP3.
- Raw .aac streams carry no seek index — tooling often prefers M4A/MP4 containers.
AMR vs AAC — Technical specifications
Side-by-side comparison of the technical details.
AMR
- MIME type
- audio/amr
- Extensions
- .amr, .3ga
- Standard
- 3GPP TS 26.071 (narrowband), TS 26.171 (wideband)
- Sample rate
- 8 kHz (AMR-NB); 16 kHz (AMR-WB)
- Bitrates
- 4.75, 5.15, 5.9, 6.7, 7.4, 7.95, 10.2, 12.2 kbps
AAC
- MIME type
- audio/aac
- Extensions
- .aac, .m4a, .mp4 (container-dependent)
- Standard
- ISO/IEC 14496-3
- Variants
- AAC-LC, HE-AAC, HE-AACv2, AAC-LD, xHE-AAC
- Sample rates
- 8-96 kHz
| Specification | AMR | AAC |
|---|---|---|
| MIME type | audio/amr | audio/aac |
| Extensions | .amr, .3ga | .aac, .m4a, .mp4 (container-dependent) |
| Standard | 3GPP TS 26.071 (narrowband), TS 26.171 (wideband) | ISO/IEC 14496-3 |
| Sample rate | 8 kHz (AMR-NB); 16 kHz (AMR-WB) | — |
| Bitrates | 4.75, 5.15, 5.9, 6.7, 7.4, 7.95, 10.2, 12.2 kbps | — |
| Variants | — | AAC-LC, HE-AAC, HE-AACv2, AAC-LD, xHE-AAC |
| Sample rates | — | 8-96 kHz |
AMR vs AAC — Typical file sizes
Approximate file sizes for common scenarios.
AMR
- 1-min voice memo 45-90 KB
- 1-hour voicemail archive 3-5 MB
AAC
- Speech podcast (64 kbps) 1 MB/min
- 3-min music track (128 kbps) 3 MB
- 3-min music track (256 kbps) 6 MB
- Broadcast-quality 5.1 (384 kbps) 9 MB for 3 min
Quality & Compatibility
Lossy-to-lossy transcoding (most cross-format audio jobs) loses a tiny amount of quality on each pass — usually inaudible at our default VBR ~190 kbps for music or 96 kbps for speech. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy is only as good as the target bitrate you choose.
Tips for Best Results
- Pick 128 kbps for podcasts and voice, 192–256 kbps for music, 320 kbps only if the audio will be edited further downstream.
- Keep the AMR master alongside the AAC — re-encoding a lossy format twice accumulates audible artefacts.
- For mono voice content, convert to mono AAC explicitly to halve file size without any quality loss.
Frequently Asked Questions
Lossy-to-lossy conversions (most combinations) re-compress the audio, which technically introduces some loss. At a 192 kbps or higher target it is inaudible on normal equipment. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy transcodes are only as good as the target bitrate you choose.
For voice content (podcasts, audiobooks, lectures) 128 kbps is indistinguishable from higher bitrates. For music, 192-256 kbps covers most listening; 320 kbps is the ceiling for AAC and the right choice for audio you plan to edit further. Above that, prefer a lossless target instead.
Yes. Title, artist, album, year and cover art travel from the AMR container to the AAC container automatically where both formats support them. If a tag field has no AAC equivalent, it is dropped silently. Use any tag editor (Mp3tag, MusicBrainz Picard) to fine-tune afterwards.
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Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.