Convert AMR to M4A

Yes, and it is worth planning around. Both formats are lossy, so the M4A encoder is working from audio that has already been through one psychoacoustic pass, and its own decisions compound the first set. At 192 kbps or above the result is still transparent for most listening. If you have a lossless master anywhere, encoding the M4A from that instead avoids the double pass entirely. AMR is a narrowband speech codec running between 4.75 and 12.2 kbps, modelling the human vocal tract rather than the full audio spectrum. An M4A holds AAC in most cases, or Apple Lossless (ALAC) when it came from a lossless rip.

Yes, and it is a genuine gain over AMR, which has nowhere dependable to store any of it. M4A carries title, artist, album, year, track number and embedded cover art in the container itself, so a music library files it correctly without a manual pass. M4A keeps rich iTunes-style metadata, chapters and artwork intact, and is the native audio format across every Apple device.

Because one side of it is a speech codec rather than a music codec. It models the human vocal tract and discards everything outside telephone bandwidth, which is fine for a voice memo and destructive for anything with instruments in it. Converting away from it cannot restore the missing frequencies — they were never encoded in the first place. AMR destroys music: its 8 kHz bandwidth removes everything above telephone frequencies, and no amount of re-encoding brings it back.

Default is 192 kbps for lossy M4A; pass-through for lossless M4A. Override to 320 kbps for audiophile or 64-96 kbps for spoken-word audiobooks (transparent for voice, halves the file size).

If AMR is lossy and M4A is lossless (e.g. MP3 → WAV), the M4A file is no better than the AMR — you can't recover information that's already been thrown away. If AMR is lossless and M4A is lossy, expect the M4A codec to recompress; at 192 kbps this is transparent for most content.

Yes — title, artist, album, year, track number, album art, and chapter markers (important for audiobooks) are read from AMR and written into the M4A container where the M4A format supports tags. M4B audiobook structure round-trips into M4B and AAX → M4B output.

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.

By default yes (48 kHz AMR → 48 kHz M4A). If you need to downsample for compatibility (e.g. 96 kHz → 44.1 kHz for CD burning) the advanced sample-rate option does this with high-quality resampling.

Yes — the loudness-normalize option applies ITU-R BS.1770 / EBU R128 normalization to the M4A output, targeting -14 LUFS (streaming standard), -16 LUFS (podcast standard), or -23 LUFS (audiobook standard). Useful when batch-converting tracks with varying mastering levels.

MP3 plays universally. AAC plays on Apple, most Android, Sonos. FLAC plays on Sonos and Android, less well on older iPods. M4B audiobooks play with chapter navigation on iOS Books, Audiobookshelf, and Smart Audiobook Player. The advanced options include device presets.

Yes — uploaded AMR files are processed in isolated workers and deleted within minutes. We never play, store, or share the audio content. Especially important when working with personal audiobook libraries.