MyMediaTools

Convert MTS to VOC — Free Online Tool

Convert MTS camcorder footage (AVCHD with H.264 video and AC-3/AAC audio) to VOC, the classic Creative Labs audio format used by DOS games and Sound Blaster hardware. This tool extracts and re-encodes the audio stream to raw unsigned 8-bit PCM, stripping the video entirely to produce a retro-compatible VOC file — all processed locally in your browser.

FFmpeg Command

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Estimated output:

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How It Works

MTS files are AVCHD containers carrying H.264 video alongside AC-3 or AAC audio, typically recorded by Sony or Panasonic camcorders. VOC is a purely audio format with no video support whatsoever, so the H.264 video stream is completely discarded during this conversion — no video re-encoding occurs. The AC-3 or AAC audio from the MTS file is decoded and then re-encoded as unsigned 8-bit PCM (pcm_u8), which is the default and most broadly compatible codec for the VOC format. Because VOC files store raw uncompressed PCM audio, the output will be lossless in terms of PCM fidelity, but since the original AC-3/AAC audio was already lossy, some quality from the original recording is not recoverable. The resulting VOC file will also be significantly larger per second of audio than the compressed AC-3/AAC source, because PCM carries no compression.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg multimedia processing tool. In this browser-based tool, FFmpeg runs as a WebAssembly binary (FFmpeg.wasm) entirely within your browser — the same command shown here can also be run locally on your desktop FFmpeg installation for files over 1 GB.
-i input.mts Specifies the input file: an MTS file in the AVCHD format, which is an MPEG-2 Transport Stream container holding an H.264 video track and AC-3 or AAC audio as recorded by Sony or Panasonic camcorders.
-c:a pcm_u8 Sets the audio codec to unsigned 8-bit PCM, which is the native audio encoding of the VOC format as used by Creative Labs Sound Blaster hardware. This decodes the lossy AC-3 or AAC audio from the MTS file and re-encodes it as uncompressed raw PCM samples. The video stream is implicitly dropped because the VOC output format has no video support.
output.voc Defines the output filename with the .voc extension, which tells FFmpeg to write the result in the Creative Labs VOC container format. The VOC format wraps the raw PCM audio in a simple typed-block structure compatible with DOS-era Sound Blaster playback APIs and modern emulators like DOSBox.

Common Use Cases

  • Sampling a short audio clip from camcorder footage to use as a sound effect in a retro DOS game or demoscene project that requires VOC-format audio assets.
  • Archiving spoken-word or environmental audio recorded on an AVCHD camcorder into the VOC format for use with vintage Sound Blaster hardware or DOSBox emulation environments.
  • Extracting event or nature sounds from MTS camcorder recordings to build a custom sound library for classic game modding communities that distribute assets in VOC format.
  • Converting a camcorder-recorded voice memo or interview segment into a VOC file for playback in a period-authentic DOS multimedia application or digital exhibit.
  • Producing VOC audio assets for a homebrew retro game that targets Sound Blaster-compatible audio output, using real-world camcorder recordings as source material.
  • Testing or demonstrating the VOC audio format in an educational context by converting recognizable real-world AVCHD footage to illustrate how early PC sound cards handled audio data.

Frequently Asked Questions

Partially. The MTS file's audio is already stored in a lossy format — either AC-3 or AAC — so any compression artifacts from the original camcorder recording are already baked in and cannot be recovered. The conversion to VOC uses unsigned 8-bit PCM (pcm_u8), which itself introduces a significant quality reduction: 8-bit PCM has a dynamic range of only about 48 dB, compared to the 96 dB of 16-bit audio. If your source MTS was recorded at high quality, you may notice an audible noise floor and reduced fidelity in the VOC output. For higher fidelity, you could modify the FFmpeg command to use pcm_s16le instead.
The video is completely discarded. VOC is a strictly audio-only format with no container support for video streams, so FFmpeg drops the H.264 video track entirely during this conversion. No video re-encoding takes place — the video data is simply not written to the output file. Only the first audio track from the MTS file is extracted and converted to PCM.
The MTS format stores audio as compressed AC-3 or AAC, which use psychoacoustic algorithms to reduce file size — often achieving compression ratios of 10:1 or more. VOC with pcm_u8 stores raw, uncompressed audio samples: every second of audio at a typical 48 kHz sample rate occupies 48,000 bytes with no compression at all. This means a 10-minute MTS file's audio track might expand from a few megabytes of AC-3 to over 27 MB as an 8-bit PCM VOC file.
Yes. VOC supports both pcm_u8 and pcm_s16le codecs. To use 16-bit signed PCM, change the FFmpeg command to: ffmpeg -i input.mts -c:a pcm_s16le output.voc. This doubles the dynamic range to approximately 96 dB and will noticeably reduce noise and improve fidelity compared to 8-bit output, at the cost of doubling the file size. Most modern Sound Blaster emulators and DOSBox support both variants.
FFmpeg processes one input file at a time, but you can batch convert using a shell loop. On Linux or macOS: for f in *.mts; do ffmpeg -i "$f" -c:a pcm_u8 "${f%.mts}.voc"; done. On Windows Command Prompt: for %f in (*.mts) do ffmpeg -i "%f" -c:a pcm_u8 "%~nf.voc". This is particularly useful for converting a full memory card of AVCHD footage into individual VOC audio files for a game sound asset library.
No. The VOC format was designed for early DOS-era Sound Blaster hardware and has essentially no metadata support by modern standards. Camcorder-specific metadata embedded in the MTS file — such as recording date, GPS coordinates, camera model, and any chapter or scene markers — is entirely lost during conversion to VOC. If preserving metadata matters, consider keeping the original MTS file as your archive copy.

Technical Notes

The VOC format originates from Creative Labs' Sound Blaster era and stores audio as a series of typed data blocks, but for practical purposes FFmpeg writes a straightforward PCM payload with a VOC header. The default codec, pcm_u8, represents audio as unsigned 8-bit samples with a center value of 128, which is the native representation expected by Sound Blaster hardware and DOS game engines. When FFmpeg decodes the MTS file's AC-3 or AAC audio track, it converts the multi-channel or stereo audio to the sample format required by pcm_u8; if your MTS contains 5.1 surround AC-3 (common on higher-end AVCHD camcorders), FFmpeg will downmix it to stereo or mono depending on the channel layout negotiation. The VOC format does not support multiple audio tracks, so only the primary audio stream from the MTS file will be written to the output. Sample rate is preserved from the source where possible, though vintage Sound Blaster hardware natively operated at 8 kHz or 22.05 kHz — if you need to target specific retro hardware, add -ar 22050 or -ar 8000 to the FFmpeg command to resample accordingly. There is no subtitle or chapter support in VOC, and no mechanism to embed cover art or any EXIF-style fields.

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