Convert OGA to VOC — Free Online Tool
Convert OGA (Ogg Audio) files to VOC format, transcoding Vorbis or FLAC audio streams into raw PCM data compatible with Creative Labs' classic Sound Blaster format. This tool is ideal for retro game development or DOS-era audio workflows where VOC's uncompressed PCM_U8 encoding is required.
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FFmpeg Command
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Estimated output:
Conversion Complete!
DownloadHow It Works
OGA files store compressed audio using codecs like Vorbis (lossy) or FLAC (lossless) inside an Ogg container. During conversion, FFmpeg fully decodes the compressed audio stream into raw PCM samples, then re-encodes it as 8-bit unsigned PCM (pcm_u8) and wraps it in the VOC container structure. There is no stream copying here — a full decode-and-re-encode pass is mandatory because VOC supports only raw PCM audio, which is fundamentally incompatible with the compressed encoding used in OGA. The resulting file is uncompressed, so expect significantly larger file sizes despite the low 8-bit depth. Any Ogg-level metadata, chapter markers, or tags present in the OGA file will be discarded, as the VOC format has no equivalent metadata structure.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, which handles the full pipeline of demuxing the OGA container, decoding the compressed audio stream (Vorbis or FLAC), and re-encoding it as raw PCM for the VOC output. |
-i input.oga
|
Specifies the input OGA file. FFmpeg automatically detects the Ogg container and identifies the enclosed audio codec (typically Vorbis or FLAC) to decode it into raw PCM samples for further processing. |
-c:a pcm_u8
|
Sets the audio codec for the output to 8-bit unsigned PCM, the native raw audio format of the Creative Labs VOC container. This encodes each audio sample as a single unsigned byte (0–255), with 128 representing silence — matching the Sound Blaster hardware's expected audio encoding. |
output.voc
|
Specifies the output filename with the .voc extension, which tells FFmpeg to mux the encoded pcm_u8 audio stream into a VOC container complete with the Creative Labs VOC file header required for compatibility with Sound Blaster playback software and DOS applications. |
Common Use Cases
- Preparing audio assets for DOS game mods or demoscene projects that require Sound Blaster-compatible VOC files
- Converting background music or sound effects stored as OGA in a modern game engine into VOC files for a retro port targeting DOS or early Windows environments
- Archivists digitizing and reformatting audio for software preservation projects that need audio in the exact format used by 1990s multimedia applications
- Developers building emulator toolchains that require VOC audio as input for Sound Blaster hardware emulation layers
- Audio engineers testing and validating how modern audio content sounds when downsampled to 8-bit unsigned PCM quality, characteristic of early PC sound hardware
Frequently Asked Questions
Yes, almost certainly. VOC files encoded with pcm_u8 use 8-bit unsigned PCM, which provides only 256 distinct amplitude levels and a dynamic range of roughly 48 dB — far below the 96 dB of 16-bit audio. Your OGA source, whether Vorbis or FLAC, almost certainly has much higher fidelity. The conversion to pcm_u8 introduces significant quantization noise, which will be audible especially in quiet passages or complex audio. This is an inherent limitation of the VOC/pcm_u8 target format, not a deficiency of the conversion process.
Yes. The VOC format also supports 16-bit signed little-endian PCM (pcm_s16le), which doubles the bit depth and dramatically improves dynamic range. You can modify the FFmpeg command to use '-c:a pcm_s16le' instead of '-c:a pcm_u8'. However, be aware that some legacy DOS applications and Sound Blaster drivers only support 8-bit VOC playback, so pcm_s16le VOC files may not be compatible with all retro software targets.
Both are lost entirely. OGA (Ogg Audio) supports Vorbis comment metadata tags and chapter markers through the Ogg container structure. The VOC format has no standardized mechanism for storing metadata or chapter information — it is a simple raw audio container designed for playback on early PC hardware. FFmpeg will silently discard all tags and chapter data during this conversion with no way to preserve them in the output file.
OGA files use compressed audio codecs — Vorbis is lossy and achieves high compression ratios, while FLAC is losslessly compressed. VOC with pcm_u8 stores every audio sample as a raw uncompressed byte with no compression whatsoever. Even at the lower fidelity of 8-bit audio, an uncompressed file will typically be much larger than a compressed OGA equivalent, especially for long audio tracks. For example, one minute of mono 44.1 kHz pcm_u8 audio consumes approximately 2.6 MB as raw data.
You can batch convert using a shell loop. On Linux or macOS, run: 'for f in *.oga; do ffmpeg -i "$f" -c:a pcm_u8 "${f%.oga}.voc"; done'. On Windows Command Prompt, use: 'for %f in (*.oga) do ffmpeg -i "%f" -c:a pcm_u8 "%~nf.voc"'. Each OGA file in the directory will be decoded and re-encoded to a corresponding VOC file. This is especially useful for game asset pipelines where you need to convert an entire sound effects library.
By default, FFmpeg preserves the original sample rate from the OGA file in the VOC output. So if your OGA file is 44100 Hz, the VOC output will also be 44100 Hz. However, many Sound Blaster and DOS applications expect VOC files at lower sample rates such as 8000 Hz, 11025 Hz, or 22050 Hz. If you need to target a specific sample rate, add '-ar 22050' (or your desired rate) to the FFmpeg command before the output filename, e.g., 'ffmpeg -i input.oga -c:a pcm_u8 -ar 22050 output.voc'.
Technical Notes
The OGA-to-VOC conversion is a full transcoding operation with no possibility of stream copying. OGA wraps Vorbis (lossy, variable-bitrate), FLAC (lossless, compressed), or Opus audio inside an Ogg container, while VOC is a flat, uncompressed PCM container with a simple header structure developed by Creative Labs circa 1989. The default output codec, pcm_u8, uses unsigned 8-bit samples where silence is represented as 128 (0x80), which is a characteristic quirk of this format. The resulting audio has a theoretical signal-to-noise ratio ceiling of about 48 dB, making it unsuitable for high-fidelity applications but perfectly appropriate for its intended retro gaming and DOS compatibility use cases. FFmpeg handles the Ogg demuxing and Vorbis/FLAC decoding automatically before encoding to pcm_u8. There is no audio quality setting available in the FFmpeg command for this output format because pcm_u8 is fully defined by its bit depth — there are no encoding parameters to tune. Channel count is preserved from the source, but note that many legacy VOC players and Sound Blaster implementations only support mono audio; stereo OGA sources should have '-ac 1' added to the command if mono compatibility is required.