AAC vs AMR
A detailed comparison of AAC Audio and AMR Audio — file size, quality, compatibility, and which format to choose for your workflow.
AAC Audio
Audio FilesAAC 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.
About AAC filesAMR Audio
Audio FilesAMR (Adaptive Multi-Rate) is an audio format optimized for speech, used in phone calls.
About AMR filesStrengths Comparison
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.
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
AAC 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.
- Lossy — not suitable for archival or studio production.
AMR 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.
- Being phased out of new devices in favor of EVS and Opus.
- Non-standard extensions and variants make tooling inconsistent.
Technical Specifications
| Specification | AAC | AMR |
|---|---|---|
| MIME type | audio/aac | audio/amr |
| Extensions | .aac, .m4a, .mp4 (container-dependent) | .amr, .3ga |
| Standard | ISO/IEC 14496-3 | 3GPP TS 26.071 (narrowband), TS 26.171 (wideband) |
| Variants | AAC-LC, HE-AAC, HE-AACv2, AAC-LD, xHE-AAC | — |
| Sample rates | 8-96 kHz | — |
| 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 |
Typical File Sizes
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
AMR
- 1-min voice memo 45-90 KB
- 1-hour voicemail archive 3-5 MB
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Frequently Asked Questions
AAC (Advanced Audio Coding) is a lossy audio format standardized by ISO as the successor to MP3. It delivers better sound quality than MP3 at equivalent bitrates and is the default audio format for Apple products, YouTube, and most streaming services.
AAC (Advanced Audio Coding) is a com perdas audio formato padrãoized by ISO como o successor to MP3. It delivers better sound quality than MP3 at equivalent bitrates e is the default audio formato para Apple products, YouTube, e most streaming services.
AAC files play in iTunes, Apple Music, VLC, Windows Media Player, and all modern web browsers. AAC is natively supported on iOS, Android, macOS, and Windows.
AAC arquivos reproduzir in iTunes, Apple Music, VLC, Windows Media Player, e all moderno web browsers. AAC is natively suportado no iOS, Android, macOS, e Windows.
AAC is technically superior, offering better quality at the same bitrate. Use AAC for Apple ecosystem and modern devices. Use MP3 only when you need compatibility with very old hardware like legacy car stereos or basic MP3 players.
AAC is technically superior, offering better quality at the same bitrate. usar AAC para Apple ecosystem e dispositivos modernoos. usar MP3 only when you need compatibilidade com very old hardware like legacy car stereos ou basic MP3 players.