Convert AIFF-C Compressed Audio (.aifc) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure audio conversion with no watermarks or registration.
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AIFC (AIFF-C) is Apple's compressed audio interchange format, a legacy container from classic Mac OS that supports IMA ADPCM, MACE 3:1/6:1, G.711 u-law/A-law, and uncompressed PCM audio. AMR (Adaptive Multi-Rate) is a speech-optimized codec developed by the European Telecommunications Standards Institute for GSM cellular networks, encoding voice at bitrates from 4.75 to 12.2 kbps.
Converting AIFC to AMR takes legacy Mac audio and encodes it into the most compact speech codec in common use. The output is a standalone AMR file (.amr) designed for voice recording apps, MMS messaging, and cellular voice infrastructure. This conversion is exclusively practical for speech content — AMR's narrow bandwidth destroys musical fidelity.
AIFC files cannot be played, shared, or processed by any modern mobile or telephony system. AMR, despite being narrowband, remains the standard voice recording format on many Android devices and is universally accepted by MMS gateways and voicemail servers worldwide. If you have legacy AIFC voice recordings that need to enter the cellular ecosystem, AMR is the target format.
The file size reduction is extreme. A one-minute AIFC file with uncompressed PCM at CD quality occupies roughly 10 MB. The same minute in AMR at 12.2 kbps is approximately 90 KB — a 100:1 compression ratio. Even MACE-compressed AIFC is several times larger than AMR. For bandwidth-constrained delivery, AMR is unmatched.
FFmpeg decodes the AIFC container (PCM, IMA ADPCM, MACE, u-law, or A-law) to raw PCM samples, downmixes stereo to mono, resamples to 8 kHz (AMR-NB) or 16 kHz (AMR-WB), and encodes using libopencore-amrnb or libopencore-amrwb. The AMR codec operates on 20 ms speech frames, applying algebraic code-excited linear prediction (ACELP) to model the vocal tract. The output is a standalone .amr file with the standard AMR magic number header.
AMR-NB limits audio to 300-3400 Hz — telephone-quality bandwidth. All high-frequency content (cymbals, sibilance, harmonics above 3.4 kHz) is permanently discarded. Music is severely degraded; speech remains clear and intelligible. AMR-WB extends to 50-7000 Hz and sounds noticeably more natural. If the AIFC source already uses MACE 6:1 compression, the quality starting point is already limited, and AMR encoding further degrades it.
| Device | AIFC | AMR |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Resolution: N/A
Bitrate: 256 kbps
AAC format required
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
AIFC to AMR converts obsolete Apple audio into the most compact speech-optimized format available. Reserve this conversion for voice content only, and choose AMR-WB when the target system supports it for improved clarity.
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Yksityisyys ensin
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Mikä tahansa selain, mikä tahansa laite
| No |
| Ominaisuus | AIFC | AMR |
|---|---|---|
| Koko nimi | AIFF-C Compressed Audio | Adaptive Multi-Rate Audio |
| Tiedostopääte | .aifc | .amr |
| Paras käyttökohde | Compressed AIFF | Speech optimized |