Convert M2TS to AMR — Free Online Tool
Convert M2TS Blu-ray and AVCHD video files to AMR audio, extracting the speech-optimized audio track encoded with the AMR-NB codec at 12,200 bps — ideal for producing compact voice recordings from camcorder footage or broadcast captures. This tool runs entirely in your browser via FFmpeg.wasm; no files leave your device.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your M2TS file here
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Settings
Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
M2TS is a MPEG-2 Transport Stream container that typically carries high-definition video (H.264 or H.265) alongside multichannel audio tracks such as AC-3, DTS, or AAC. During this conversion, FFmpeg discards the video stream entirely and transcodes the first audio track into AMR-NB (Adaptive Multi-Rate Narrowband) using the libopencore_amrnb encoder at a fixed bitrate of 12,200 bps. AMR-NB is a narrowband codec that operates on 8 kHz sampled audio, so the full-bandwidth audio from the M2TS source — which may be 48 kHz stereo or surround — is downsampled to 8 kHz mono. The result is a highly compact .amr file optimized for intelligible speech, not music or cinematic audio.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg multimedia processing tool, which in this browser-based implementation runs as a WebAssembly binary (FFmpeg.wasm) without any server involvement — your M2TS file is processed entirely locally in your browser tab. |
-i input.m2ts
|
Specifies the input file — an M2TS BDAV MPEG-2 Transport Stream, which may contain HD video, multichannel audio (AC-3, DTS, AAC), subtitles, and multiple language tracks. FFmpeg demuxes all streams from this container before the output mapping is applied. |
-c:a libopencore_amrnb
|
Selects the libopencore_amrnb encoder to transcode the audio into AMR Narrowband format, automatically downmixing any stereo or surround audio from the M2TS to mono and resampling it from its native rate (typically 48 kHz) to the 8 kHz rate required by AMR-NB. The video stream is implicitly dropped because the AMR output container cannot hold video. |
-b:a 12200
|
Sets the AMR-NB encoding bitrate to 12,200 bits per second, which corresponds to AMR mode 7 — the highest quality and highest bitrate mode available in AMR-NB. This provides the best speech intelligibility the format can offer from the M2TS audio source. The value is in bits per second, not kilobits, because AMR-NB modes use sub-kilobit increments. |
output.amr
|
Defines the output file as a .amr file using the AMR container format, which stores a single AMR-NB encoded audio stream. The .amr extension ensures compatibility with mobile devices, telephony systems, and voice applications that recognize the standard AMR file signature. |
Common Use Cases
- Extracting a spoken interview or commentary track from AVCHD camcorder footage (.m2ts) for use in a mobile voice transcription app that accepts AMR files
- Pulling a narration or voiceover recorded to Blu-ray-standard M2TS by a broadcast team and converting it to AMR for archival in a telecommunications or IVR system
- Reducing a large M2TS conference recording to a tiny AMR file to share via legacy MMS messaging or embedded in a system that only supports narrowband speech formats
- Converting spoken-word content captured by an AVCHD camcorder on location into AMR for import into mobile telephony middleware or SIP-based VoIP platforms
- Preprocessing M2TS field recordings from a broadcast camera for speech recognition pipelines that require 8 kHz mono AMR-NB input
- Archiving the dialogue or announcement audio from a Blu-ray production master into an AMR format suited for low-storage, speech-centric archives
Frequently Asked Questions
No — AMR-NB is specifically engineered for human speech and performs very poorly on music, sound effects, or full-bandwidth audio. It resamples everything to 8 kHz mono, which eliminates most of the frequency range present in M2TS audio tracks (which are typically 48 kHz stereo or 5.1 surround). If your M2TS contains music or cinematic audio, a format like MP3 or AAC is far more appropriate. AMR should only be used when the content is primarily spoken voice.
By default, FFmpeg selects the first audio stream in the M2TS file, which is typically the primary language track. M2TS files from Blu-ray discs often contain multiple audio tracks (e.g., different languages or commentary). If you want a specific track, you would add a stream selector such as '-map 0:a:1' to pick the second audio stream before the output filename in the FFmpeg command.
AMR-NB (Narrowband) operates at 8 kHz sample rate and bitrates up to 12,200 bps, while AMR-WB (Wideband) operates at 16 kHz and supports bitrates up to 23,850 bps. This tool uses AMR-NB via libopencore_amrnb, which is the most universally supported AMR variant. If your use case involves higher-quality speech (e.g., HD Voice on modern VoIP systems) and your target platform supports AMR-WB, you could modify the command to use '-c:a libopencore_amrwb' with a compatible wideband bitrate. For basic mobile telephony compatibility, AMR-NB at 12,200 bps is the standard choice.
Replace the value after '-b:a' in the command with one of the valid AMR-NB bitrates: 4750, 5150, 5900, 6700, 7400, 7950, 10200, or 12200 (in bits per second, not kilobits). For example, to use the lowest bitrate for maximum compression, the flag would be '-b:a 4750'. Note that AMR-NB only accepts these specific fixed values — arbitrary bitrates are not supported, and FFmpeg will snap to the nearest valid mode if given an unrecognized value.
Dramatically smaller. An M2TS file from an AVCHD camcorder or Blu-ray rip typically runs at 15–40 Mbps due to its HD video stream. Once the video is stripped and audio is encoded as AMR-NB at 12,200 bps (approximately 1.5 KB/s), even an hour of audio results in a file of only about 5–6 MB. A 10-minute M2TS that might be 1–2 GB will produce an AMR file of under 1 MB, though all video, surround channels, and high-frequency audio content will be lost in the process.
Yes. On Linux or macOS you can use a shell loop: 'for f in *.m2ts; do ffmpeg -i "$f" -c:a libopencore_amrnb -b:a 12200 "${f%.m2ts}.amr"; done'. On Windows Command Prompt, the equivalent is 'for %f in (*.m2ts) do ffmpeg -i "%f" -c:a libopencore_amrnb -b:a 12200 "%~nf.amr"'. Batch processing is especially useful for this conversion because the browser-based tool is best suited for single files up to 1 GB, whereas local FFmpeg handles large collections of M2TS files from a camcorder card efficiently.
Technical Notes
AMR-NB encoding imposes hard constraints that anyone converting from M2TS must understand. First, AMR-NB mandates mono audio at an 8 kHz sample rate — FFmpeg will automatically downmix stereo or multichannel M2TS audio to mono and resample from the source rate (typically 48 kHz) to 8 kHz. This means stereo separation, surround channels (AC-3 5.1, DTS, etc.), and all audio content above 4 kHz is permanently discarded. Second, the libopencore_amrnb encoder only accepts the eight standardized AMR mode bitrates; values outside this set cause FFmpeg to select the nearest valid mode, so always use an explicit, valid '-b:a' value. Third, no metadata from the M2TS container — chapter markers, subtitle streams, secondary audio tracks, or Blu-ray-specific navigation data — is preserved in the AMR output, as the .amr format supports only a single raw audio stream with a minimal header. Finally, because the AMR codec was designed for telephone-grade speech, any M2TS source containing background music, ambient sound, or effects will exhibit significant perceptual artifacts and frequency distortion in the output — this conversion is only appropriate when the audio content is predominantly spoken voice.