FLAC (Free Lossless Audio Codec) is the gold standard for audio archiving and high-fidelity listening. But what happens when you need to split a FLAC file? Can you divide it without losing the perfect quality that makes FLAC special?
The answer is yes - and in this guide, you'll learn exactly how to split FLAC files while preserving every bit of audio quality.
Understanding FLAC: Why Lossless Matters
Before diving into splitting, let's understand what makes FLAC different from formats like MP3:
| Feature | FLAC (Lossless) | MP3 (Lossy) |
|---|---|---|
| Quality | Identical to source | Reduced (perceptually similar) |
| Compression | ~50-60% of WAV | ~10% of WAV |
| Re-encoding loss | None (mathematically perfect) | Cumulative degradation |
| Best for | Archiving, audiophiles, masters | Portable devices, streaming |
The key insight: FLAC compression is reversible. Unlike MP3, which permanently discards audio data, FLAC simply compresses data like a ZIP file. You can decompress it to get the exact original audio back.
How Lossless Splitting Works
When you split a FLAC file properly, here's what happens:
- Decode: FLAC is decompressed to raw PCM (pulse-code modulation) audio data
- Split: The PCM data is divided at sample boundaries
- Re-encode: Each segment is compressed back to FLAC (or saved as WAV)
Because FLAC decompression is mathematically perfect, and PCM splitting preserves all samples, the entire process is 100% lossless. The audio in your split files is bit-for-bit identical to the corresponding portions of the original.
Technical Note: ChunkAudio outputs WAV files (uncompressed lossless) rather than re-encoding to FLAC. This is because browser-based FLAC encoding is complex. You can easily convert the WAV outputs to FLAC afterward using free tools - no quality is lost in this extra step.
Step-by-Step: Split FLAC Files Online
1 Open ChunkAudio
Navigate to ChunkAudio's Audio Splitter. No installation required - it works entirely in your web browser.
2 Upload Your FLAC File
Drag and drop your FLAC file onto the upload area, or click to browse. The file is processed locally - nothing is uploaded to any server, ensuring your audio stays private.
3 Choose Split Method
Select how you want to divide your FLAC file:
- By Duration: Create segments of specific length
- By Number of Parts: Divide into equal parts
- By File Size: Create parts that fit size constraints
4 Process and Download
Click "Split Audio". Your browser decodes the FLAC, splits the PCM data, and outputs WAV files. Download individually or as a ZIP archive.
5 Convert Back to FLAC (Optional)
To save space, convert the WAV files back to FLAC using any of these free tools:
- fre:ac: Free, cross-platform, batch conversion
- FFmpeg: Command line, powerful and fast
- VLC: Media player with built-in conversion
- dBpoweramp: Windows, excellent metadata handling
Common FLAC Splitting Scenarios
Splitting Album Rips into Tracks
Many vinyl or CD rips exist as single FLAC files for an entire album. If you have a CUE sheet, it contains the exact track boundaries. You can:
- Use desktop tools like CUETools or Medieval CUE Splitter for automatic splitting
- Reference the CUE sheet timestamps and split manually using ChunkAudio's duration option
Creating Samples from Long Recordings
If you have a long live recording or field recording in FLAC, you can split it into shorter segments for easier browsing and sharing while maintaining full quality.
Preparing Files for Limited Storage Devices
Some portable players have file size limits. Split large FLAC files into smaller segments that fit your device's constraints.
Split Your FLAC Files Losslessly
Preserve every bit of audio quality with our free online splitting tool.
Try ChunkAudio FreeFLAC vs Other Lossless Formats
FLAC isn't the only lossless format. Here's how it compares:
| Format | Compression | Compatibility | Notes |
|---|---|---|---|
| FLAC | Best (50-60% of WAV) | Excellent (most devices) | Open source, most popular |
| ALAC | Good (similar to FLAC) | Apple ecosystem | Apple's lossless codec |
| WAV | None (uncompressed) | Universal | Largest files, simplest |
| AIFF | None (uncompressed) | Mac-focused | Apple's uncompressed format |
| WavPack | Best (with hybrid mode) | Limited | Niche, powerful features |
ChunkAudio supports all these formats for input and outputs WAV, which can then be converted to any other lossless format without quality loss.
High-Resolution FLAC Considerations
FLAC files can store high-resolution audio beyond CD quality:
- CD quality: 16-bit, 44.1 kHz
- High-res: 24-bit, 96 kHz or higher
- Studio master: 24-bit, 192 kHz
ChunkAudio preserves the original bit depth and sample rate when splitting. A 24-bit/96kHz FLAC file outputs 24-bit/96kHz WAV segments.
High-Res File Sizes: 24-bit/96kHz FLAC files are significantly larger than CD quality. Ensure you have sufficient browser memory for very large files. For files over 500MB, consider using desktop software like Audacity or splitting in stages.
Verifying Lossless Quality After Splitting
If you want to confirm that your split files are truly lossless:
Method 1: Checksum Comparison
Decode your original FLAC and split files to PCM. Use a hex editor or tool to compare the raw audio data - it should be byte-identical within each segment.
Method 2: Spectrum Analysis
Use Audacity or Spek to view the frequency spectrum. Lossless files show full frequency response up to the Nyquist frequency (half the sample rate). MP3s show visible cutoffs.
Method 3: Dynamic Range Meter
Check the DR (dynamic range) values using tools like foobar2000's DR Meter. Split lossless files should have identical DR values to the original.
Converting WAV Outputs Back to FLAC
After splitting, you'll want to convert your WAV files back to FLAC to save space. Here's how with popular tools:
Using FFmpeg (Command Line)
Fast and scriptable for batch conversion:
ffmpeg -i input.wav -c:a flac output.flac
Using VLC (GUI)
- Media -> Convert / Save
- Add your WAV files
- Select FLAC as output format
- Start conversion
Using fre:ac (Batch GUI)
- Download and install fre:ac (free, open source)
- Drag all WAV files into the window
- Select FLAC as output encoder
- Click Start to batch convert
Frequently Asked Questions
Is FLAC truly lossless when split?
Yes, FLAC is a lossless codec, meaning the audio data is mathematically identical to the source. When you split a FLAC file properly (decoding to PCM and re-encoding), the audio quality remains perfect - bit-for-bit identical to the original within each segment. No information is discarded at any step.
Why does ChunkAudio output WAV instead of FLAC?
WAV is the intermediate lossless format used during processing. Browser-based FLAC encoding is technically complex and computationally intensive. WAV output ensures maximum compatibility and speed. You can easily convert the WAV files back to FLAC using free tools like fre:ac, FFmpeg, or VLC - no quality is lost in this extra step.
Can I split a FLAC album with CUE sheet?
CUE sheets define track boundaries in a single FLAC file. While ChunkAudio doesn't read CUE files directly, you can use the timestamps from your CUE sheet to calculate durations and split manually. For automated CUE splitting with track metadata, desktop tools like CUETools or Medieval CUE Splitter are purpose-built for this task.
How much larger are split FLAC files compared to the original?
The total size of split files is nearly identical to the original. FLAC compression works on small audio frames, so splitting doesn't significantly affect the compression ratio. You might see a tiny increase due to additional file headers in each output file, but it's negligible - usually less than 1% total.
Can I split high-resolution FLAC files (24-bit/96kHz)?
Yes, ChunkAudio fully supports high-resolution FLAC files including 24-bit audio at sample rates up to 192kHz. The tool preserves the original bit depth and sample rate in the output WAV files. After conversion back to FLAC, your files maintain their original high-resolution specifications.