Extract Audio from M4V to AMR — Free Online Tool
Extract audio from M4V iTunes video files and convert it to AMR format using the libopencore_amrnb codec — optimized for speech and voice content. AMR's narrow-band compression makes it ideal for stripping dialogue or voiceover from M4V video for use in mobile telephony, voice messaging, or low-bandwidth speech applications.
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FFmpeg Command
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Estimated output:
Conversion Complete!
DownloadHow It Works
This tool strips the video stream entirely from the M4V container and transcodes the AAC audio track (M4V's default audio codec) into AMR-NB (Adaptive Multi-Rate Narrow-Band) using the libopencore_amrnb encoder. Because AAC and AMR are completely different audio codecs, a full re-encoding of the audio is required — this is not a simple remux. The AMR codec was specifically engineered for speech signals and uses dynamic bitrate modes ranging from 4,750 to 12,200 bps, far lower than typical AAC bitrates in M4V files. The output is a raw .amr file containing only the audio, with no video, subtitle, or chapter data carried over from the original M4V.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, which handles the decoding of the M4V container, audio transcoding pipeline, and writing of the output AMR file entirely on your local machine. |
-i input.m4v
|
Specifies the input M4V file. FFmpeg reads and demuxes the M4V container, identifying its video stream (typically H.264) and audio stream (typically AAC) for processing. |
-vn
|
Disables video output entirely, instructing FFmpeg to ignore the H.264 or H.265 video stream from the M4V. Since AMR is an audio-only format, this flag is required to produce a valid output file. |
-c:a libopencore_amrnb
|
Selects the libopencore_amrnb encoder to transcode the M4V's AAC audio into AMR Narrow-Band format. This triggers a full re-encode — not a copy — because AAC and AMR-NB are entirely different codecs with different compression algorithms and frequency targets. |
-b:a 12200
|
Sets the AMR-NB bitrate to 12,200 bits per second, which corresponds to Mode 7 — the highest quality operating mode available in AMR-NB. This gives the best speech intelligibility the format can produce from the original M4V audio. |
output.amr
|
Defines the output filename with the .amr extension. FFmpeg uses this extension to select the AMR file format muxer, which writes the encoded audio with the standard ISF AMR header recognized by mobile devices and telephony systems. |
Common Use Cases
- Extracting spoken dialogue or narration from an iTunes M4V lecture or educational video to send as a voice note via a mobile messaging app that accepts AMR attachments
- Converting the audio track from an M4V audiobook or spoken-word video download into AMR for playback on older feature phones or embedded devices that support AMR but not AAC
- Stripping the voiceover from an M4V tutorial video to create a lightweight AMR file for review or transcription on low-bandwidth mobile connections
- Archiving the speech audio from iOS-recorded M4V video clips in AMR format for integration into a telecom or IVR system that requires AMR-encoded voice prompts
- Extracting interview audio from an M4V video file to share as an AMR voice memo compatible with legacy Android or Symbian devices
- Preparing speech audio from an M4V video for use in a voice recognition or speech analysis pipeline that expects AMR-NB encoded input
Frequently Asked Questions
Yes, expect a noticeable quality reduction, especially for music or complex audio. AMR-NB is engineered exclusively for speech in the 300–3400 Hz frequency range, so it discards most of the frequency content that AAC preserves. At the default 12,200 bps bitrate (AMR's highest mode), speech remains intelligible and clear, but any music, ambient sound, or wide-frequency audio in the original M4V will sound thin and degraded. This conversion is best suited for M4V files containing primarily voice content.
No. AMR-NB is strictly a mono, single-channel format. If your M4V file contains stereo or multi-channel AAC audio, FFmpeg will automatically downmix it to mono during the conversion. Additionally, AMR does not support multiple audio tracks — only one audio stream will be present in the output .amr file, regardless of how many tracks existed in the source M4V.
None of this data carries over. M4V is a feature-rich container that can hold chapters, subtitles, multiple audio tracks, and iTunes-specific metadata tags. AMR is a bare audio format with no container features of this kind — it holds only the encoded speech bitstream. All chapters, subtitle tracks, cover art, and metadata from the M4V will be lost in the output .amr file.
Replace the value after -b:a with one of the eight AMR-NB mode bitrates: 4750, 5150, 5900, 6700, 7400, 7950, 10200, or 12200 (in bits per second, not kilobits). For example, to use the lowest bitrate mode, change the command to: ffmpeg -i input.m4v -vn -c:a libopencore_amrnb -b:a 4750 output.amr. Lower modes produce smaller files but reduced speech clarity, while 12200 (the default here) gives the best quality AMR-NB can offer.
The displayed command processes one file at a time, but you can batch it with a shell loop. On Linux or macOS, run: for f in *.m4v; do ffmpeg -i "$f" -vn -c:a libopencore_amrnb -b:a 12200 "${f%.m4v}.amr"; done. On Windows Command Prompt, use: for %f in (*.m4v) do ffmpeg -i "%f" -vn -c:a libopencore_amrnb -b:a 12200 "%~nf.amr". Note that libopencore_amrnb must be compiled into your local FFmpeg build for this to work.
The libopencore_amrnb encoder is not included in all FFmpeg builds due to licensing considerations — it requires FFmpeg to be compiled with --enable-libopencore-amrnb. Standard builds from ffmpeg.org's static binaries typically include it, but some package manager distributions (such as certain Linux repos) ship a restricted build that omits it. Check your build's codec support by running ffmpeg -codecs | grep amr. If it's missing, download a full-featured static build from the official FFmpeg website or a trusted third-party like gyan.dev (Windows).
Technical Notes
AMR-NB (Narrow-Band), implemented here via libopencore_amrnb, operates at a fixed 8,000 Hz sample rate with mono channel audio — a significant constraint compared to the 44,100 Hz or 48,000 Hz stereo AAC typically found in M4V files. FFmpeg will automatically resample the audio to 8 kHz during this conversion, which is the primary source of the audible quality reduction on non-speech content. The eight AMR bitrate modes are not continuous like typical audio encoders; they are discrete codec operating modes (Mode 0 through Mode 7), and FFmpeg maps the -b:a value to the nearest valid mode. The default of 12,200 bps corresponds to Mode 7, AMR-NB's highest quality setting. M4V files protected with Apple FairPlay DRM cannot be processed — only DRM-free M4V files (such as those from personal recordings or DRM-free iTunes purchases) will convert successfully. The output .amr file uses the simple storage format (ISF) with a magic number header (#!AMR\n), which is broadly compatible with mobile platforms but lacks the richer metadata support of formats like MP4 or OGG.