AMR to MP3 Converter for Call Recordings

How to convert an AMR file

1. Copy the .amr file to your computer, or open this page on the phone itself, and choose the file above.
2. The tool suggests 128 kbps, which is more than enough for phone audio.
3. Convert and download the MP3.

What AMR is

Adaptive Multi-Rate (AMR) is a speech codec standardised for mobile phone networks. The common narrowband version records at 8 kHz, which captures the frequencies of a voice and little else, at bitrates between 4.75 and 12.2 kbps. That makes files tiny: a minute takes well under 100 KB. A wideband version, AMR-WB, records at 16 kHz for clearer "HD voice" audio. The converter reads both.

Why it sounds thin, and what converting does

Narrowband AMR keeps roughly the range of an old landline call, so it lacks the low warmth and high crispness of a normal recording. Converting to MP3 can't add that back. What it does is make the recording playable everywhere. The MP3 is resampled to 44.1 kHz, the standard rate every player supports, and at 128 kbps it will be many times the size of the AMR while sounding exactly as it did.

Call recordings and privacy

Call recordings often involve another person's voice and sensitive details. Converting them on an upload site sends a copy to a stranger's server. This converter runs in your browser: the AMR file is read from your device and the MP3 saved back to it, with nothing transmitted. Check the recording laws where you live before recording or sharing calls.

From call recording to transcript

mydubly doesn't accept AMR uploads, so convert to MP3 first, then use the audio to text tool for a timestamped transcript. Phone-quality audio is harder for speech recognition than a good microphone; the phone call transcription article explains what to expect and how to get the best result.

How the free converter works

The converter is ffmpeg, the open-source media toolkit, compiled to WebAssembly so it runs inside your browser tab. Your file is read straight from your disk by that engine; it is never uploaded to mydubly or anywhere else, and no account is needed.

• The engine is about 30 MB and downloads the first time you convert something. After that your browser normally keeps it.
• Large inputs are fine because the file is read in place, but the result is built in memory, so outputs are capped at about 1.5 GB.
• Speed depends on your device. Copying streams takes seconds; re-encoding video is the slow case.
• Keep the tab open until the download button appears. Closing it stops the conversion.