Convert FLAC to captions

Create accessible closed captions from your lossless FLAC audio. Professional-quality captions from the highest quality source audio.

ADA compliant
5-min turnaround
Accessible
Audio
Video
DOCX
SRT/VTT
PDF
53+ Languages
About This Format

Understanding FLAC files

What is a FLAC file?

Lossless audio compression - CD quality at half the size

Free Lossless Audio Codec file (FLAC) is an audio format similar to MP3, but lossless. What does this mean? The audio in a FLAC file is compressed without any loss in quality, whereas a MP3 file compresses the audio but usually lowers the quality of the file by excluding certain frequencies. A FLAC file works similar to how a ZIP file is compressed. Since FLAC is highly optimized for audio, you’ll receive a better compression ratio when compared to the ZIP compression algorithms. You can play compressed FLAC files in your favorite media player (including VLC, your car, or home stereo, or computer) just like you would an MP3 file (without having to uncompress it separately).
FLAC files are one of the fastest and most widely supported lossless audio codecs and is one of the few that are non-proprietary and has a well-documented open-source reference implementation. There are no attached patents for FLAC files. It was developed in 2000 and FLAC files discourage developers to not include any DRM features.

Common Uses

  • Audiophile music collections
  • Music archiving
  • High-fidelity audio
  • Lossless music streaming

Audio Quality

Bit-perfect lossless compression - identical to original

Transcription Tips for FLAC

  • Excellent for transcription - no quality loss from compression
  • Smaller than WAV but same audio quality
  • Well-suited for interview and podcast archiving

Where FLAC Files Come From

  • Bandcamp downloads
  • HD music stores
  • Audio archivists
  • Tidal streaming rips
10x
Faster than real-time
Get your FLAC captions in minutes
99%
Accuracy rate
Industry-leading AI for FLAC files
53+
Languages
Captions in any language
30+
Export formats
SRT, VTT, SCC, and more
How It Works

Create captions from FLAC in 6 steps

Step 1

Create account

Sign up for Sonix's free trial. Includes 30 minutes free.

Step 2

Upload file

Upload your FLAC file from your computer or cloud storage.

Step 3

Select language

Choose from 53+ languages spoken in your file.

Step 4

Auto-transcribe

Sonix AI transcribes your FLAC with word-level timestamps.

Step 5

Edit captions

Fine-tune timing and formatting for accessibility.

Step 6

Export

Download closed captions in SRT, VTT, or SCC format.

Common Questions

Everything about FLAC captions

Why use FLAC for professional captions?

FLAC's lossless audio provides the clearest source for caption transcription. When accuracy is critical, FLAC source files deliver the best possible results.

Are FLAC-to-caption conversions ADA compliant?

Sonix generates captions meeting ADA requirements. FLAC's perfect quality helps achieve accuracy levels exceeding professional captioning standards.

Can I add sound descriptions to FLAC captions?

Yes! After transcription, add non-speech descriptions like [music], [applause], or [door closes] in Sonix's editor.

How accurate are AI captions from FLAC?

Sonix achieves 99%+ accuracy on clear FLAC audio, often exceeding this due to the pristine lossless quality.

What caption format works for broadcast FLAC?

For broadcast television, export to SCC or STL formats which meet FCC requirements.

Can I caption FLAC files with multiple speakers?

Yes! Speaker detection works excellently with FLAC's perfect audio quality. Each speaker gets labeled captions.

Why Sonix

Accessible captions from FLAC files

Accessibility First

Create captions that make your content accessible to deaf and hard-of-hearing viewers.

ADA Compliant

Meet accessibility requirements with properly formatted closed captions.

Sound Descriptions

Add non-speech elements like [music] and [applause] for full context.

SEO Benefits

Captions make video content searchable and improve discoverability.

Reviews

Trusted by accessibility teams

4.98 rating from 211 reviews

English dictation is very accurate. And the online editor is easy to use. Also it generates SRT files that I can import in my video editors for further processing.
MC
Michael C.
Aberdeen, Hong Kong
I really like it. Easy to use, very accurate, and easy to correct when it is not. A truly super program, and I would recommend it to anyone.
WP
Wayne P.
Pflugerville, TX
You guys saved me hours of work, reduced my stress level the moment I started and saw the first result coming in.
DV
David V.
Sofia, Bulgaria
I love Sonix. It's accurate, intuitive, friendly and simple to use for the technically inept like me! I typically use it for English but we used it this time in French and it was g...
SR
Sairica R.
San Juan de La Rambla, Spain
It was so easy and convenient to use. The transcripts require minimal editing and the delivery time is fantastic!
GS
Georgette S.
Toronto, Canada
Sonix is light years ahead of all the other solutions I researched and tried!
GB
Garth B.
Calgary, Canada
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