Extract Audio from MTS to WMA — Free Online Tool
Extract audio from MTS camcorder footage and save it as a WMA file — ideal for pulling AC-3 or AAC audio tracks from AVCHD recordings into a Windows-native format. The audio is re-encoded using the wmav2 codec, producing a compact, widely compatible Windows Media Audio file without retaining any video data.
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FFmpeg Command
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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
MTS files are AVCHD recordings typically captured by Sony or Panasonic camcorders, wrapping H.264 video alongside AC-3 or AAC audio inside an MPEG-2 Transport Stream container. This tool discards the video stream entirely and re-encodes the audio track from its original AC-3 or AAC encoding into WMA using Microsoft's wmav2 codec. Because the source audio codec is incompatible with the WMA container, a full audio transcode is required — there is no lossless stream copy possible here. The resulting .wma file contains only the audio, encoded at 128kbps by default, inside Microsoft's proprietary ASF container that underpins the WMA format.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool, which handles all demuxing, decoding, encoding, and muxing operations. When run via this web tool, it executes as FFmpeg.wasm inside your browser with no server involvement. |
-i input.mts
|
Specifies the input AVCHD file in MTS format — an MPEG-2 Transport Stream typically produced by Sony or Panasonic camcorders containing H.264 video and AC-3 or AAC audio. |
-vn
|
Disables video output entirely, instructing FFmpeg to ignore the H.264 video stream from the MTS file so that only the audio is processed and included in the output WMA file. |
-c:a wmav2
|
Sets the audio encoder to wmav2 (Windows Media Audio version 2), Microsoft's standard lossy audio codec and the only format natively supported by the WMA/ASF container. The source AC-3 or AAC audio from the MTS file is fully decoded and re-encoded using this codec. |
-b:a 128k
|
Sets the target audio bitrate to 128 kilobits per second for the wmav2 encoder. This is a standard mid-quality setting suitable for voice and general audio; raise it to 192k or 256k if the source MTS footage contains music or high-fidelity stereo recordings. |
output.wma
|
Defines the output filename and triggers FFmpeg to mux the encoded wmav2 audio into an ASF/WMA container. The .wma extension is recognized natively by Windows Media Player and other Windows-ecosystem applications. |
Common Use Cases
- Extracting interview or dialogue audio from AVCHD camcorder footage to edit in Windows-native applications like Windows Movie Maker or older versions of Microsoft Expression Encoder
- Pulling ambient sound or location audio from MTS recordings captured on a Sony Handycam or Panasonic HC series camcorder for use in a Windows-based multimedia project
- Converting camcorder-recorded event audio (speeches, ceremonies, concerts) from MTS into WMA for distribution via older Windows Media Player-based kiosks or digital signage systems
- Archiving the audio commentary track from MTS home videos into a smaller, audio-only WMA file to save storage while discarding the accompanying video
- Preparing audio from AVCHD footage for playback on legacy Windows devices, portable media players, or Xbox consoles that support WMA but not MTS or raw AAC files
- Extracting a stereo music or soundtrack recording captured via camcorder in MTS format into a WMA file for sharing via email or platforms that accept WMA attachments
Frequently Asked Questions
Yes, some quality loss is unavoidable because this conversion involves two stages of lossy compression. The original MTS file already stores audio in either AC-3 or AAC — both lossy formats — and re-encoding that into wmav2 at 128kbps introduces a second generation of compression artifacts. For speech and dialogue the result is generally acceptable, but for music or high-fidelity recordings, you should increase the bitrate to 192k or 256k to minimize audible degradation.
The WMA container (built on Microsoft's ASF format) only supports wmav1 and wmav2 audio codecs. The audio inside MTS files is encoded as AC-3 (Dolby Digital) or AAC, neither of which can be stored in an ASF/WMA container. Because the codec must change, a full re-encode from the source audio to wmav2 is required — stream copying with '-c:a copy' is not an option for this format pair.
Replace '128k' in the '-b:a 128k' flag with your desired bitrate. For example, use '-b:a 192k' or '-b:a 256k' for higher quality output. WMA supports bitrates up to 320kbps with wmav2. If you are extracting audio from a camcorder recording that captured music or high-quality stereo sound, 192k is a practical balance between file size and fidelity.
MTS files embed minimal metadata in the MPEG-2 Transport Stream headers, and most camcorder-specific tags (model, GPS, scene info) are not preserved during conversion to WMA. The WMA/ASF container does support standard metadata fields like title, artist, and album, but FFmpeg will only carry over metadata that maps between the two formats. You should expect to lose camcorder-specific technical metadata in the output file.
Yes. On Linux or macOS, you can run a shell loop: 'for f in *.mts; do ffmpeg -i "$f" -vn -c:a wmav2 -b:a 128k "${f%.mts}.wma"; done'. On Windows Command Prompt, use: 'for %f in (*.mts) do ffmpeg -i "%f" -vn -c:a wmav2 -b:a 128k "%~nf.wma"'. This processes every MTS file in the current directory and outputs a corresponding WMA file with the same base name.
WMA is not recommended for archival purposes. It is a proprietary Microsoft format with historically limited support outside of Windows ecosystems, and future software compatibility is not guaranteed. If your goal is long-term preservation of audio extracted from AVCHD footage, open formats like FLAC (lossless) or AAC/Opus (lossy but open) are better choices. WMA is most appropriate when the output needs to target Windows Media Player, older Windows devices, or platforms that specifically require WMA files.
Technical Notes
The MTS container is an MPEG-2 Transport Stream, a broadcast-derived format designed for robust transmission. When extracting audio from MTS, FFmpeg must demux the transport stream to isolate the audio PID (Packet Identifier) before decoding and re-encoding it. If the MTS file contains multiple audio tracks (e.g., a stereo main track and a separate narration track, which AVCHD permits), FFmpeg will by default select the first detected audio stream. Use '-map 0:a:1' in the command to explicitly select an alternate audio track. The WMA format uses Microsoft's ASF (Advanced Systems Format) container and only supports single audio streams — any multichannel audio beyond stereo may be downmixed depending on the wmav2 encoder's channel handling. The wmav2 codec performs adequately in the 128k–192k bitrate range for speech but can exhibit pre-echo and smearing artifacts on transient-heavy material like percussion at lower bitrates. Note also that WMA lacks support for chapters and subtitles, so any subtitle streams in the original MTS file are silently dropped.