MyMediaTools

Extract Audio from MTS to VOC — Free Online Tool

Extract audio from AVCHD camcorder footage (.mts) and save it as a VOC file — the classic Creative Labs audio format used in DOS-era games and multimedia. The AC-3 or AAC audio track from your MTS file is decoded and re-encoded as raw 8-bit unsigned PCM, producing a VOC file fully compatible with vintage Sound Blaster software and retro game engines.

FFmpeg Command

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Estimated output:

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How It Works

MTS files are MPEG-2 Transport Stream containers carrying H.264 video alongside AC-3 or AAC audio, as recorded by Sony and Panasonic camcorders. During this conversion, FFmpeg discards the H.264 video stream entirely using the -vn flag, then decodes the compressed AC-3 or AAC audio to raw PCM. That raw audio is then re-encoded as 8-bit unsigned PCM (pcm_u8) and written into a VOC container — the format originally designed by Creative Labs for the Sound Blaster card. Because VOC only supports a single audio track and no compressed codecs, this is a full decode-and-re-encode of the audio, not a stream copy. The result is a lossless PCM file in a retro-compatible wrapper, though the 8-bit depth means significantly lower dynamic range than the original camcorder audio.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg tool, which handles all decoding, audio processing, and re-encoding for this MTS-to-VOC conversion entirely within your browser via WebAssembly.
-i input.mts Specifies the input AVCHD camcorder file in MTS format, which contains an H.264 video stream and compressed AC-3 or AAC audio in an MPEG-2 Transport Stream container.
-vn Disables video output entirely, ensuring the H.264 video stream from the MTS file is ignored and not processed — this is an audio-only extraction to VOC.
-c:a pcm_u8 Sets the audio codec to 8-bit unsigned PCM, which is the native audio encoding of early VOC files designed for the Creative Labs Sound Blaster card. The compressed AC-3 or AAC audio from the MTS file is fully decoded and then re-encoded to this raw 8-bit format.
output.voc Specifies the output file in VOC format — the Creative Labs Sound Blaster audio container. FFmpeg infers the VOC muxer from the .voc file extension and writes the pcm_u8 audio data into this retro-compatible wrapper.

Common Use Cases

  • Extracting a voiceover or dialogue recording made on a Sony or Panasonic camcorder for use as a sound effect or voice line in a DOS game or retro game engine that only accepts VOC files.
  • Converting AVCHD camcorder audio into VOC format for playback through vintage Sound Blaster hardware or period-accurate DOS emulators like DOSBox.
  • Preparing audio assets recorded in the field on an AVCHD camcorder for import into classic multimedia authoring tools like Asymetrix Toolbook or early Macromedia Director versions that support VOC.
  • Archiving a specific audio moment from MTS camcorder footage — such as a speech or event recording — in the VOC format for a retro computing collection or museum exhibit.
  • Supplying ambient sound or narration recorded via AVCHD to an open-source retro game project where the audio pipeline is built around the VOC format.
  • Testing or demonstrating Sound Blaster audio playback compatibility using real-world recorded audio rather than synthesized or pre-existing DOS-era samples.

Frequently Asked Questions

Yes, there will be a noticeable quality reduction due to the 8-bit unsigned PCM format used in VOC files. While VOC pcm_u8 is technically lossless in the sense that it stores raw PCM without compression artifacts, 8-bit audio has a dynamic range of only about 48 dB, compared to the 16-bit or higher quality of the original AC-3 or AAC audio in your MTS file. This means quieter sounds may be lost in quantization noise and the audio will sound grainier than the source. This is expected and characteristic of the VOC format's era.
Yes. VOC files support both pcm_u8 and pcm_s16le (16-bit signed little-endian PCM), and using pcm_s16le gives you a much higher dynamic range — approximately 96 dB versus 48 dB for 8-bit. To use it, change the command to: ffmpeg -i input.mts -vn -c:a pcm_s16le output.voc. Note that not all retro software and hardware supports 16-bit VOC files, as early Sound Blaster cards only handled 8-bit audio, so check your target application's compatibility before switching.
By default, FFmpeg selects the first audio stream it finds in the MTS file, which is typically the primary stereo or surround AC-3 track recorded by the camcorder. VOC files only support a single audio track, so only one stream can be included. If you need a specific track — for example, a secondary audio channel recorded on a different mic input — you can specify it with the -map flag: ffmpeg -i input.mts -map 0:a:1 -vn -c:a pcm_u8 output.voc, where 0:a:1 selects the second audio stream.
No. The VOC format was designed purely for audio sample data and has no metadata fields beyond basic audio parameters like sample rate and bit depth. Any metadata embedded in the MTS file — including recording timestamps, GPS coordinates, camera model, or copyright tags — will be lost during conversion. If metadata preservation is important, consider extracting the audio to a format like FLAC or WAV, which support metadata tags, before converting to VOC for specific retro use.
You can process multiple files using a shell loop. On Linux or macOS, run: for f in *.mts; do ffmpeg -i "$f" -vn -c:a pcm_u8 "${f%.mts}.voc"; done. On Windows Command Prompt, use: for %f in (*.mts) do ffmpeg -i "%f" -vn -c:a pcm_u8 "%~nf.voc". Each MTS file in the folder will be processed sequentially and output as a VOC file with the same base filename. This is especially useful when you have a batch of camcorder clips from a shoot that all need audio extracted for a retro game project.
Early VOC files and some retro applications only support mono audio, and FFmpeg may downmix stereo to mono depending on the codec configuration and target sample rate. If you want to explicitly keep stereo output (where the VOC format and your target software support it), you can add -ac 2 to the command: ffmpeg -i input.mts -vn -c:a pcm_u8 -ac 2 output.voc. Conversely, if you intentionally need mono for DOSBox or vintage Sound Blaster compatibility, add -ac 1 to force a mono downmix.

Technical Notes

VOC files store audio as raw uncompressed PCM with a simple header that encodes sample rate, bit depth, and channel count — there is no container-level compression, chapter support, subtitle support, or metadata beyond these basic parameters. The default codec used here, pcm_u8, encodes each sample as an unsigned 8-bit integer, which was the native format for the original Sound Blaster ISA cards. The source MTS audio — whether AC-3 (Dolby Digital) or AAC — must be fully decoded before writing to VOC, so this is never a stream copy operation. Sample rate conversion may also occur: if the MTS audio is recorded at 48 kHz (standard for camcorders), FFmpeg will retain that rate in the VOC file, but some retro applications expect 22050 Hz or 11025 Hz VOC files, so you may need to add -ar 22050 to the command for compatibility. File sizes for pcm_u8 VOC output are relatively small compared to 16-bit formats — roughly 48 KB per second of mono audio at 48 kHz — but much larger than the compressed AC-3 or AAC source. There are no special FFmpeg flags required for VOC output beyond the codec selection, as the format is straightforward with no complex muxer options.

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