Convert VOC to ALAC — Free Online Tool
Convert VOC audio files — the raw PCM format used by Creative Labs Sound Blaster cards in DOS-era games — to ALAC (Apple Lossless Audio Codec) stored in an M4A container. This is a fully lossless conversion: every audio sample from the original VOC file is preserved exactly in the compressed ALAC output, making it ideal for archiving retro game audio in a modern, Apple-compatible format.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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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
VOC files store uncompressed PCM audio (typically 8-bit unsigned PCM at low sample rates like 8kHz or 22kHz, or 16-bit signed little-endian PCM) with a simple header structure developed by Creative Labs. During this conversion, FFmpeg reads the raw PCM samples from the VOC container and re-encodes them using the ALAC codec, which applies lossless compression — similar in principle to ZIP compression but optimized for audio waveforms. The resulting file is wrapped in an MPEG-4 (M4A) container. Because both the source and destination are lossless, the decoded audio output is bit-for-bit identical to the original PCM data. The only transformation is the container format and the addition of lossless compression to reduce file size.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — the open-source multimedia processing engine running here via WebAssembly in your browser. The same binary can be installed on your desktop to run this command locally for files over 1GB. |
-i input.voc
|
Specifies the input file — a VOC file created by or for a Creative Labs Sound Blaster card. FFmpeg will detect the VOC container format and identify the PCM codec (pcm_u8 or pcm_s16le) automatically from the VOC block headers. |
-c:a alac
|
Sets the audio codec to ALAC (Apple Lossless Audio Codec), instructing FFmpeg to encode the raw PCM audio from the VOC file into lossless ALAC compression. This flag appears twice in the command; the second instance is redundant but harmless — the effective instruction is the same. |
-c:a alac
|
A duplicate of the preceding audio codec flag. FFmpeg accepts this without error, applying the last specified value — which is again ALAC. If running this command manually on your desktop, you can safely omit this second instance. |
output.m4a
|
Defines the output file. The .m4a extension tells FFmpeg to wrap the ALAC-encoded audio in an MPEG-4 container, which is the standard and Apple-compatible packaging for ALAC audio. This file can be played natively by iTunes, Apple Music, iPhone, and macOS without any additional codecs. |
Common Use Cases
- Archiving sound effects and music ripped from classic DOS games (e.g., Doom, Duke Nukem, Wing Commander) in a lossless format playable on modern Apple devices
- Importing retro game audio into a macOS or iOS music library via iTunes or the Music app, which natively supports ALAC but cannot play VOC files
- Preserving original Sound Blaster 8-bit audio samples for use in modern DAWs or sample libraries without any quality degradation
- Converting VOC voice lines or sound effects extracted from a DOS game for use in a podcast, video essay, or documentary about retro gaming history
- Migrating a collection of legacy multimedia VOC files from an old DOS machine into a format compatible with Apple ecosystem tools like Logic Pro or GarageBand
- Creating a lossless master archive of VOC audio before any further lossy conversion (e.g., to MP3 or AAC) for distribution
Frequently Asked Questions
No — this conversion is entirely lossless. VOC files store raw PCM audio, and ALAC is a lossless compression codec, meaning ALAC encodes the PCM samples in a way that can be decoded back to the exact original values. The 8-bit or 16-bit fidelity of the original Sound Blaster audio is fully preserved; ALAC simply reduces the file size through compression without discarding any data.
Yes, FFmpeg will read the 8-bit unsigned PCM (pcm_u8) from the VOC file and the ALAC encoder will preserve the original sample rate and bit depth. However, be aware that 8-bit audio has inherent low fidelity — that characteristic lo-fi Sound Blaster sound is baked into the source data itself. ALAC preserves that exactly; it does not upgrade or upsample the audio during this conversion.
Yes. ALAC in an M4A container is natively supported across the entire Apple ecosystem, including iPhone, iPad, Mac, Apple TV, and the Apple Music and iTunes applications. This is one of the primary advantages of converting VOC files to ALAC — you get lossless quality in a format that Apple devices can play without any additional software or codecs.
That is a redundancy in the generated command — the flag '-c:a alac' appears twice in a row, which is functionally harmless because FFmpeg processes the last value for a given option. In practice, the command works correctly and the audio is encoded as ALAC. If you are running this command locally on your desktop, you can safely remove the duplicate flag and use 'ffmpeg -i input.voc -c:a alac output.m4a' for a cleaner command.
On Linux or macOS, you can use a shell loop: 'for f in *.voc; do ffmpeg -i "$f" -c:a alac "${f%.voc}.m4a"; done'. On Windows Command Prompt, use: 'for %f in (*.voc) do ffmpeg -i "%f" -c:a alac "%~nf.m4a"'. This applies the same lossless ALAC conversion to every VOC file in the current directory, producing individual M4A output files.
VOC files have very minimal metadata support — typically just a version header and block-type markers, with no fields for track title, artist, or album. When converting to M4A/ALAC, FFmpeg will carry over any metadata it can parse, but in practice you will likely end up with an ALAC file with no embedded tags. You can add metadata manually using FFmpeg's '-metadata' flag (e.g., '-metadata title="Level 1 Theme"') or a tag editor like MusicBrainz Picard after conversion.
Technical Notes
VOC files were designed for the Creative Labs Sound Blaster ISA card and support two main PCM formats: unsigned 8-bit (pcm_u8) at sample rates typically ranging from 8kHz to 22kHz, and signed 16-bit little-endian (pcm_s16le) at higher rates. The format uses a chunked block structure (data blocks, silence blocks, loop blocks) that FFmpeg fully understands. When converting to ALAC, FFmpeg reads these PCM blocks and feeds the raw samples to the ALAC encoder, which applies a linear predictive coding (LPC) algorithm for lossless compression — typically achieving 40–60% size reduction over raw PCM, though the actual ratio depends heavily on the audio content. The M4A container (MPEG-4 Part 14) used for ALAC output supports chapter markers, but VOC files have no chapter data to carry over. Similarly, VOC does not support multiple audio tracks or subtitles, so the output will always be a single-track ALAC file. One practical note: because many VOC files are sourced from DOS games and recorded at 8kHz mono with 8-bit depth, the output ALAC file will faithfully preserve those constraints — ALAC is not a resampler or upscaler, it is purely a lossless codec.