MyMediaTools

Convert MOV to AMR — Free Online Tool

Convert MOV video files to AMR audio, extracting and re-encoding the audio track using the libopencore_amrnb codec — a narrowband speech codec originally designed for GSM mobile networks. Ideal for isolating voice recordings from QuickTime video files into a compact, telephony-compatible format.

FFmpeg Command

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Estimated output:

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How It Works

During this conversion, FFmpeg discards the video stream entirely and extracts the audio track from the MOV container. The audio — which in a typical MOV file is encoded as AAC or another broadband codec — is then transcoded (fully re-encoded) into AMR-NB (Adaptive Multi-Rate Narrowband) using the libopencore_amrnb encoder. AMR-NB operates at a fixed 8kHz sample rate, so FFmpeg will automatically downsample the source audio to match. The result is a very small .amr file optimized for speech intelligibility at low bitrates, at the cost of music quality, stereo channels, and any non-audio data (chapters, subtitles, multiple audio tracks) present in the original MOV file.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg multimedia processing tool. In this browser-based tool, FFmpeg runs entirely via WebAssembly (FFmpeg.wasm) inside your browser — no file data leaves your device.
-i input.mov Specifies the input file — a MOV (QuickTime) container, which may contain video, audio, chapters, and subtitle streams. FFmpeg will parse all streams but only the audio will be used in this conversion.
-c:a libopencore_amrnb Sets the audio codec to libopencore_amrnb, an open-source encoder for the AMR Narrowband standard. This re-encodes the MOV file's audio (typically AAC) into the AMR-NB format, automatically downsampling to 8kHz mono to comply with the codec's fixed requirements.
-b:a 12200 Sets the AMR-NB encoding mode to 12.2 kbps, which is the highest quality mode available in the AMR-NB standard and offers the best speech intelligibility. This value must match one of AMR-NB's eight fixed bitrate modes; 12200 is the default and recommended choice for most voice recording use cases.
output.amr Defines the output filename with the .amr extension, which FFmpeg uses to write the resulting AMR-NB audio file. The .amr container is minimal — it stores only the raw AMR audio frames with a short file header and carries no video, metadata, or chapter information from the original MOV.

Common Use Cases

  • Extracting voice memos or interview recordings captured as MOV files on an iPhone or mirrorless camera for use in mobile telephony systems or IVR platforms that require AMR input
  • Converting QuickTime screen recordings of video calls or lectures into compact AMR files for archiving spoken-word content with minimal storage overhead
  • Preparing voice-over or narration audio recorded in Final Cut Pro and exported as MOV for upload to legacy mobile communication systems that only accept AMR format
  • Stripping audio from MOV field recordings to create AMR-formatted audio samples compatible with older feature phones or embedded telephony hardware
  • Reducing file size of spoken-word MOV recordings for transmission over bandwidth-constrained networks where only speech intelligibility matters

Frequently Asked Questions

Yes, and significantly so for anything beyond speech. AMR-NB is a narrowband codec that samples audio at only 8kHz, which means frequencies above 4kHz — present in music, background noise, and most broadband audio — are completely cut off. Your MOV file's AAC or PCM audio track, which typically captures up to 20kHz, will sound noticeably muffled and telephone-like after conversion. For voice recordings where only speech intelligibility matters, the quality is acceptable; for music or rich soundscapes, AMR is the wrong target format.
AMR-NB is inherently a mono format, so FFmpeg will automatically downmix your MOV file's stereo (or multichannel) audio to a single mono channel during conversion. If your MOV has separate left and right channels with distinct content, that spatial information will be lost. The downmix averages the channels, so voices panned to center will generally survive well, but stereo music or dual-language tracks will be collapsed into a single blend.
These numbers are bitrates in bits per second corresponding to AMR-NB's standardized codec modes. The default of 12200 bps (12.2 kbps) is the highest quality AMR-NB mode and produces the most intelligible speech. Lower modes like 4750 bps (4.75 kbps) compress more aggressively and are suitable for low-bandwidth voice transmission but introduce more artifacts. Unlike MP3 or AAC where bitrate changes are gradual, AMR uses a fixed set of discrete encoding modes — you cannot specify an arbitrary bitrate.
No. AMR is a bare audio format with virtually no metadata container support. Chapter markers, subtitle tracks, multiple audio streams, and even basic tags like title or artist that may exist in your MOV file will be stripped entirely during conversion. If preserving metadata is important, you should save it separately before converting, as the AMR format has no standardized way to store it.
Replace the value after -b:a in the command with one of the valid AMR-NB mode bitrates: 4750, 5150, 5900, 6700, 7400, 7950, or 10200 (in bits per second). For example, to use the most compressed mode, run: ffmpeg -i input.mov -c:a libopencore_amrnb -b:a 4750 output.amr. Note that AMR-NB does not accept arbitrary bitrate values — FFmpeg will snap to the nearest valid mode if you enter something non-standard, so it's best to use one of the defined values explicitly.
Yes, on Linux or macOS you can use a shell loop: for f in *.mov; do ffmpeg -i "$f" -c:a libopencore_amrnb -b:a 12200 "${f%.mov}.amr"; done. On Windows Command Prompt, use: for %f in (*.mov) do ffmpeg -i "%f" -c:a libopencore_amrnb -b:a 12200 "%~nf.amr". The browser-based tool processes one file at a time, so the FFmpeg command is especially useful when you need to convert large batches or files over 1GB.

Technical Notes

The libopencore_amrnb encoder is an open-source implementation of the 3GPP AMR-NB standard (as defined in ETSI TS 126 092) and must be compiled into FFmpeg — it is not included in default builds due to patent considerations, though it is available in most binary distributions like FFmpeg.wasm. AMR-NB is strictly limited to 8kHz sample rate, mono channel, and one of eight fixed bitrate modes ranging from 4.75 to 12.2 kbps. FFmpeg will automatically insert a sample rate conversion (resampling) step when processing MOV files whose audio tracks operate at standard rates like 44.1kHz or 48kHz, using its built-in resampler. If your MOV contains multiple audio tracks, FFmpeg will select the first audio stream by default; use -map 0:a:1 to target a specific track. The AMR file format itself uses the .amr extension and a simple file header (magic bytes '#!AMR
') with no support for embedded album art, lyrics, or chapter data. For wideband speech at higher quality, consider AMR-WB (libopencore_amrwb) which operates at 16kHz — though support for AMR-WB playback is less universal than AMR-NB on legacy devices.

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