Extract Audio from MPEG to VOC — Free Online Tool
Extract audio from MPEG video files and save it as a VOC file — the classic Sound Blaster format used in DOS-era games and multimedia. The audio is decoded from MPEG's MP2 or MP3 stream and re-encoded to raw PCM (pcm_u8), producing an uncompressed 8-bit unsigned PCM audio file compatible with vintage Sound Blaster hardware and DOS applications.
to
FFmpeg Command
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Estimated output:
Conversion Complete!
DownloadHow It Works
MPEG files typically carry audio encoded in MP2 (MPEG Layer II) or occasionally MP3 or AAC. During this conversion, FFmpeg discards the video stream entirely using the -vn flag, then decodes the compressed MPEG audio and re-encodes it as unsigned 8-bit PCM (pcm_u8) — the default and most compatible codec for the VOC container. VOC is a simple, headerless-style format developed by Creative Labs, and unlike the lossy MPEG audio source, the output PCM data is uncompressed. However, because pcm_u8 is 8-bit audio, there is a reduction in dynamic range compared to modern 16-bit or 24-bit formats — this is intentional for VOC compatibility rather than a conversion artifact.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool. In the browser-based version of this tool, FFmpeg runs locally via WebAssembly (FFmpeg.wasm) — no data is sent to a server. The same command can be run identically on any desktop with FFmpeg installed. |
-i input.mpeg
|
Specifies the input MPEG file. FFmpeg reads the MPEG program or transport stream, which contains MPEG-1/2 video and typically MP2 audio tracks that will be processed in subsequent steps. |
-vn
|
Disables video output entirely. Since this is an audio extraction tool, the MPEG-1 or MPEG-2 video stream is discarded, and only the audio stream is passed through for decoding and re-encoding into the VOC file. |
-c:a pcm_u8
|
Sets the audio codec to unsigned 8-bit PCM, which is the native and most compatible audio encoding for the VOC format. The compressed MPEG audio (MP2/MP3) is fully decoded and then re-encoded as raw 8-bit PCM to match the Sound Blaster VOC specification. |
output.voc
|
Defines the output filename with the .voc extension, which tells FFmpeg to write a Creative Labs VOC container. The resulting file is an uncompressed 8-bit PCM audio file ready for use with Sound Blaster hardware, DOSBox, or DOS-era multimedia software. |
Common Use Cases
- Extracting dialogue or sound effects from MPEG video footage to use as VOC samples in a DOS game or retro game mod
- Preparing audio assets from MPEG-encoded training or educational videos for playback in legacy DOS-based kiosk or multimedia systems that only support Sound Blaster VOC files
- Converting MPEG broadcast clips or archival video audio into VOC format for use with vintage Creative Labs Sound Blaster cards in period-accurate retro PC builds
- Generating VOC audio assets from modern MPEG source video for inclusion in DOSBox game setups, demoscene productions, or other DOS emulation environments
- Stripping and archiving audio tracks from old MPEG-1 home video or VCD recordings into the VOC format as part of a retro multimedia preservation project
Frequently Asked Questions
Yes, in a nuanced way. The MPEG audio (typically MP2 or MP3) is already lossy, so some quality was lost when the MPEG file was originally created. Converting to VOC with pcm_u8 produces uncompressed audio, but 8-bit unsigned PCM has limited dynamic range (only 256 quantization levels), which introduces a characteristic lo-fi quality compared to 16-bit audio. If preserving fidelity is important, you can use the pcm_s16le codec instead, though many VOC players and DOS applications expect 8-bit audio.
Yes. VOC files produced with pcm_u8 encoding are directly compatible with DOSBox's Sound Blaster emulation and most DOS-era software that supports Creative Labs VOC audio. The format was designed specifically for this ecosystem. Just ensure the sample rate of the source audio matches what your target application expects, as some DOS programs are hardcoded to specific sample rates like 22050 Hz or 11025 Hz.
The VOC format supports both 8-bit unsigned (pcm_u8) and 16-bit signed little-endian (pcm_s16le) PCM, but pcm_u8 is the historical default — it matches the original Sound Blaster hardware capabilities and is what most DOS-era software expects. The FFmpeg command uses pcm_u8 for maximum retro compatibility. If your target application supports 16-bit VOC, you can change -c:a pcm_u8 to -c:a pcm_s16le in the command for better dynamic range.
No. The VOC format does not support metadata tags of any kind — it is a raw audio container with no provisions for embedding title, artist, album, or other descriptive information. Any ID3 or metadata tags present in the MPEG file will be discarded during conversion. This is a fundamental limitation of the VOC format, not a tool limitation.
You can add the -ar flag to specify a target sample rate. For example, to output at 22050 Hz (common in DOS games), use: ffmpeg -i input.mpeg -vn -ar 22050 -c:a pcm_u8 output.voc. Lowering the sample rate reduces file size and can improve compatibility with older Sound Blaster models that top out at 22050 Hz or 11025 Hz. Without the -ar flag, FFmpeg will use the source MPEG audio's original sample rate.
Yes. On Linux or macOS, you can run a simple shell loop: for f in *.mpeg; do ffmpeg -i "$f" -vn -c:a pcm_u8 "${f%.mpeg}.voc"; done. On Windows Command Prompt, use: for %f in (*.mpeg) do ffmpeg -i "%f" -vn -c:a pcm_u8 "%~nf.voc". This applies the same extraction and pcm_u8 encoding to every MPEG file in the directory, producing a matching VOC file for each.
Technical Notes
MPEG files use a program stream or transport stream container carrying video (MPEG-1 or MPEG-2) and audio (most commonly MP2, sometimes MP3 or AAC). When extracting audio for VOC output, FFmpeg fully decodes the compressed MPEG audio to PCM internally before re-encoding it to pcm_u8 — this is a full transcode, not a stream copy, because VOC and MPEG audio are entirely different codecs. The VOC format was designed around the constraints of early 1990s Sound Blaster hardware: it supports only mono or stereo audio, no multi-track audio, no subtitles, and no chapters. The pcm_u8 codec stores audio as unsigned 8-bit values (0–255), centered at 128, which gives a theoretical signal-to-noise ratio of about 49 dB — noticeably lower than 16-bit audio's ~96 dB. File sizes will be larger than the original MPEG audio because PCM is uncompressed, but VOC files from typical MPEG sources are still modest in size given the 8-bit depth. One known limitation is that VOC does not carry sample rate metadata in the same way modern formats do — some playback tools may need the sample rate specified manually if it deviates from their default assumption.