Extract Audio from M2TS to VOC — Free Online Tool
Extract audio from M2TS Blu-ray and AVCHD files and save it as a VOC file using unsigned 8-bit PCM encoding — the raw audio format developed by Creative Labs for DOS-era Sound Blaster hardware. This tool strips all video, subtitle, and secondary audio tracks from the M2TS container and outputs a single uncompressed mono or stereo audio stream in the retro VOC format, entirely in your browser.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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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 high-definition transport stream container typically carrying compressed audio codecs such as AAC, AC-3, DTS, or TrueHD alongside H.264 or H.265 video. During this conversion, FFmpeg discards all video streams entirely and decodes whichever audio track is selected (defaulting to the first available track) into raw PCM samples. Those samples are then re-encoded as unsigned 8-bit PCM (pcm_u8) and written into a VOC container — Creative Labs' legacy Sound Blaster format from the early 1990s. Because VOC only supports a single audio track and does not understand the multi-track, multi-stream structure of M2TS, only the primary audio stream is extracted. The high-bit-depth, high-sample-rate audio from the Blu-ray source is downconverted to fit the limitations of 8-bit unsigned PCM, which is a significant quality reduction but is required for genuine VOC compatibility.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — the open-source multimedia processing engine that powers this conversion. In the browser-based tool, this runs via FFmpeg.wasm, a WebAssembly port that executes the same logic client-side without uploading your M2TS file to any server. |
-i input.m2ts
|
Specifies the input file as an M2TS transport stream. FFmpeg will probe the container to detect all streams present — typically H.264 or H.265 video, one or more audio tracks (AAC, AC-3, TrueHD, DTS, etc.), and possibly PGS subtitle streams embedded in the Blu-ray or AVCHD structure. |
-vn
|
Disables video output entirely, telling FFmpeg to ignore all video streams in the M2TS file. Since the goal is audio extraction into a VOC file — which has no video support whatsoever — this flag ensures no attempt is made to encode or mux the H.264/H.265 video track. |
-c:a pcm_u8
|
Sets the audio codec to unsigned 8-bit PCM, the native encoding used by the original Creative Labs Sound Blaster card. The M2TS audio stream (regardless of whether it was AAC, AC-3, or lossless TrueHD) is decoded to raw PCM and then quantized down to 8-bit unsigned samples to produce a genuine VOC-compatible audio stream. |
output.voc
|
Specifies the output filename with the .voc extension, which causes FFmpeg to select the Creative Voice File muxer. The resulting file will have a valid VOC header recognized by Sound Blaster utilities, DOSBox, and other retro-compatible audio players. |
Common Use Cases
- Sampling dialogue or sound effects from a Blu-ray rip to use in a DOS game mod or retro game project that requires Sound Blaster-compatible VOC assets
- Extracting a short audio clip from an AVCHD camcorder recording to embed in a legacy multimedia application or interactive demo that only accepts VOC input
- Creating period-accurate audio assets from modern HD video sources for a demoscene production targeting real DOS hardware or DOSBox emulation
- Pulling the audio track from a Blu-ray concert or film M2TS file to quickly audition its content using an old Sound Blaster utility or a VOC-capable media player
- Converting a voice-over or narration recorded on an AVCHD camcorder into a VOC file for use in a retro-style point-and-click adventure game engine that natively supports the Creative Labs format
- Archiving or cataloging audio content from an M2TS source in VOC format as part of a preservation project focused on DOS-era multimedia interactivity
Frequently Asked Questions
Significantly reduced, unfortunately. M2TS files typically carry audio encoded at 24-bit depth, 48 kHz or higher sample rates, often in lossless formats like TrueHD or DTS-HD MA. VOC with pcm_u8 encoding is limited to 8-bit unsigned PCM, which gives you only 256 discrete amplitude levels compared to the millions available at 24-bit. The result is noticeably lower dynamic range and increased quantization noise, which is inherent to the format rather than a flaw in the conversion. This is appropriate if you specifically need Sound Blaster-compatible VOC files, but if you want high-quality audio extraction from M2TS, a format like FLAC or WAV would be a far better choice.
FFmpeg will select the first audio stream in the M2TS file by default, which is typically the primary language track. M2TS files from Blu-ray discs often contain multiple tracks — for example, a lossless TrueHD main track plus a Dolby Digital compatibility track, or multiple language dubs. Because VOC does not support multiple audio tracks, only one stream can be written to the output. If you want to extract a specific track rather than the default, you can modify the FFmpeg command to add '-map 0:a:1' (for the second audio stream) or '-map 0:a:2' for the third, before the output filename.
Yes, VOC files can carry stereo audio, so if your M2TS source is stereo or if FFmpeg downmixes a surround track to stereo, the output VOC file will be stereo. However, compatibility with older Sound Blaster hardware and some legacy software may vary — early Sound Blaster cards and DOS utilities sometimes only expected mono VOC files. If you encounter playback issues in retro environments, you can add '-ac 1' to the FFmpeg command to force a mono downmix before the output filename.
Both are discarded entirely. M2TS supports embedded subtitle tracks (PGS bitmap subtitles are common on Blu-ray) and the source file may have chapter metadata, but VOC is a simple raw audio container with no provision for subtitles, chapters, or any non-audio data. The '-vn' flag in the command explicitly drops the video stream, and since VOC has no subtitle or chapter support, all such metadata is silently ignored during muxing.
The VOC format itself does not have a quality parameter like bitrate, since pcm_u8 is uncompressed, but you can control the sample rate by adding '-ar 22050' or '-ar 44100' before the output filename in the command. For example: 'ffmpeg -i input.m2ts -vn -ar 22050 -c:a pcm_u8 output.voc'. Lower sample rates reduce file size and are more compatible with original Sound Blaster hardware limits (the original SB supported up to 22 kHz in stereo). Omitting '-ar' lets FFmpeg pass through whatever sample rate the M2TS audio stream uses, which may be 48 kHz.
Yes, the displayed command is designed for a single file, but you can adapt it for batch processing in a shell script. On Linux or macOS, use: 'for f in *.m2ts; do ffmpeg -i "$f" -vn -c:a pcm_u8 "${f%.m2ts}.voc"; done'. On Windows Command Prompt, use: 'for %f in (*.m2ts) do ffmpeg -i "%f" -vn -c:a pcm_u8 "%~nf.voc"'. This is particularly useful for processing collections of AVCHD recordings or Blu-ray chapter files, which are often split across many .m2ts files. The browser-based tool handles files up to 1 GB, so local FFmpeg is recommended for large batches.
Technical Notes
The VOC format was designed by Creative Labs in the early 1990s and is one of the oldest PC audio container formats still recognized by FFmpeg. It uses a chunked structure with a file header identifying it as a Creative Voice File, followed by data blocks. FFmpeg's VOC muxer supports two codecs: pcm_u8 (unsigned 8-bit, the classic Sound Blaster format) and pcm_s16le (signed 16-bit little-endian, a later extension). This conversion uses pcm_u8 by default, matching the most widely compatible Sound Blaster mode. A key limitation is that VOC does not carry rich metadata — no title, album, artist, or language tags from the M2TS source are preserved. The M2TS container can hold multiple audio streams with stream-level language metadata (ISO 639 language codes), but all of this is stripped on output. Additionally, if the source M2TS carries surround audio (5.1 or 7.1 channels), FFmpeg will automatically downmix to stereo or mono depending on the channel layout negotiation, since pcm_u8 in VOC does not support discrete surround channels. File sizes for VOC output depend entirely on duration and sample rate: at 44.1 kHz mono pcm_u8, one minute of audio occupies approximately 2.6 MB — much smaller than the M2TS source but comparable to uncompressed WAV at the same settings.