Convert FLAC to VOC — Free Online Tool
Convert FLAC lossless audio files to VOC format using the pcm_u8 codec — the raw 8-bit unsigned PCM encoding used by Creative Labs' Sound Blaster hardware. This tool runs entirely in your browser via FFmpeg.wasm, making it ideal for preparing retro game audio assets or DOS-era sound effects without installing any software.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your FLAC file here
or click to browse
Free — no uploads, no signups. Your files never leave your browser.
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
FLAC stores audio as losslessly compressed integer samples, which FFmpeg first decodes into raw PCM. During conversion to VOC, those decoded samples are re-encoded as unsigned 8-bit PCM (pcm_u8) — a very shallow bit depth of 0–255 per sample, centered at 128 for silence. This is a genuine quality reduction: FLAC typically carries 16- or 24-bit audio, and squeezing it into 8-bit introduces quantization noise and reduces dynamic range to roughly 48 dB. The resulting VOC file uses the classic Creative Labs container format, which embeds the raw PCM data in typed data blocks with a simple header, making it directly compatible with DOS Sound Blaster drivers and retro game engines.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — in this browser tool, that is FFmpeg compiled to WebAssembly (ffmpeg.wasm), which runs the identical conversion logic locally in your browser without sending any data to a server. |
-i input.flac
|
Specifies the input FLAC file. FFmpeg reads the FLAC container, identifies the losslessly compressed audio stream, and decodes it to raw PCM internally before applying the output codec. |
-c:a pcm_u8
|
Sets the audio codec for the output to pcm_u8 — 8-bit unsigned PCM, the encoding natively used by Creative Labs Sound Blaster hardware and required by most DOS applications that read VOC files. This is where the bit-depth reduction from FLAC's 16/24-bit source to 8-bit occurs. |
output.voc
|
Specifies the output filename with the .voc extension, which tells FFmpeg to use the Creative Voice File muxer and write the pcm_u8 audio data into the VOC container format with its characteristic 'Creative Voice File' header block structure. |
Common Use Cases
- Preparing sound effects for DOS game mods or recreations that require Sound Blaster-compatible VOC assets
- Converting a high-quality FLAC music archive into period-accurate 8-bit audio for use in retro demoscene productions
- Replacing or patching audio files in classic DOS games (such as those using the iD Software or LucasArts engines) that load .voc files directly
- Creating lo-fi 8-bit audio samples from pristine FLAC recordings for use in chiptune or retro-aesthetic music production
- Archiving or restoring original VOC-format audio from FLAC backups for vintage computer emulation environments like DOSBox
Frequently Asked Questions
Yes — this conversion is lossy in practice even though both formats store raw PCM rather than using perceptual compression. FLAC typically encodes at 16 or 24 bits per sample, while the default VOC output uses pcm_u8, which is only 8-bit unsigned PCM. This limits dynamic range to about 48 dB and introduces audible quantization noise, especially in quiet passages. The original FLAC file is not modified, so you retain the lossless source.
Yes. VOC supports pcm_s16le (signed 16-bit little-endian PCM), which preserves far more dynamic range. To use it, change the FFmpeg command to: ffmpeg -i input.flac -c:a pcm_s16le output.voc. Note that not all DOS-era software or Sound Blaster hardware modes support 16-bit VOC playback, so check your target application's compatibility before switching.
No. The VOC format does not support embedded metadata tags. All Vorbis comment tags present in your FLAC file — including artist, album, title, and ReplayGain values — will be discarded during conversion. If metadata preservation matters, keep your original FLAC files as the archival source.
By default, FFmpeg preserves the input sample rate from the FLAC file. However, the original Sound Blaster hardware and many DOS applications that use VOC files only support limited sample rates (commonly 8000, 11025, 22050, or 44100 Hz). If your FLAC is at 48000 Hz or higher, you may want to resample it explicitly by adding -ar 22050 (or another target rate) to the FFmpeg command to ensure compatibility with your target application.
On Linux or macOS, you can run: for f in *.flac; do ffmpeg -i "$f" -c:a pcm_u8 "${f%.flac}.voc"; done. On Windows (Command Prompt), use: for %f in (*.flac) do ffmpeg -i "%f" -c:a pcm_u8 "%~nf.voc". This applies the same pcm_u8 encoding used by this browser tool to every FLAC file in the current directory.
FLAC uses lossless compression that typically reduces file size by 40–60% compared to raw PCM. VOC stores audio as uncompressed raw PCM with no compression whatsoever, so the output file size is determined purely by duration, sample rate, and bit depth. Even though the bit depth drops to 8-bit (halving the per-sample size compared to 16-bit FLAC source), the absence of compression in VOC often results in a file that is larger than the FLAC source for the same audio content.
Technical Notes
The VOC format was designed in the early 1990s for Creative Labs' Sound Blaster cards and uses a chunked block structure with a 'Creative Voice File' ASCII header. FFmpeg supports writing VOC with two audio codecs: pcm_u8 (8-bit unsigned, the default and most universally compatible with DOS software) and pcm_s16le (16-bit signed little-endian, supported by later SB16-class hardware). The pcm_u8 encoding used in this tool represents silence as 128 and encodes the full waveform in the 0–255 range, which is a fundamentally different representation from the signed integers used in FLAC — FFmpeg handles this conversion transparently. VOC has no support for metadata tags, chapters, cue sheets, or ReplayGain data, all of which are features FLAC supports and which will be silently dropped. The format also does not support multi-channel audio beyond mono and stereo in typical implementations, so surround-encoded FLAC files will be downmixed. For DOSBox or other emulators, VOC files are typically loaded directly by the game engine without any additional configuration.