Convert GSM to VTT

Sonix transcribes your GSM file and exports it as WebVTT captions perfect for HTML5 video and web platforms.

HTML5 ready
5-min turnaround
Web compatible
Audio
Video
DOCX
SRT/VTT
PDF
53+ Languages
About This Format

Understanding GSM files

What is a GSM file?

Telephone-quality audio for voicemail and calls

GSM is a compressed audio stream that is primarily used by cell phones. GSM files are designed for telephone-quality audio use in Europe and stores audio mainly for telephone quality voice. It makes for a good balance between size of file and quality retention with data around 96KB per minute. GSM is primarily used for voicemail storage or to record phone conversations that will be played back later.

Common Uses

  • Voicemail storage
  • Phone call recordings
  • Telephony applications

Audio Quality

Telephone-grade audio; good for speech, not music

Transcription Tips for GSM

  • Optimized for voice - excellent for speech transcription
  • Limited frequency range (telephone quality)

Where GSM Files Come From

  • Voicemail systems
  • PBX recordings
  • Call center recordings
10x
Faster than real-time
Get your GSM VTT in minutes
99%
Accuracy rate
Industry-leading AI for GSM files
53+
Languages
Captions in any language
30+
Export formats
VTT, SRT, text, and more
How It Works

Convert GSM to VTT in 6 steps

Step 1

Create account

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

Step 2

Upload file

Upload your GSM 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 and timestamps your GSM audio.

Step 5

Edit captions

Fine-tune caption timing and text with our editor.

Step 6

Export VTT

Download your GSM captions as a WebVTT file.

Common Questions

Everything about GSM to VTT

Can you convert GSM to VTT captions?

Yes! Sonix transcribes your GSM file with precise timestamps and exports it as WebVTT captions for web video.

What is a VTT file?

WebVTT (Web Video Text Tracks) is the native caption format for HTML5 video. It's supported by all modern browsers and video platforms.

VTT vs SRT - which should I use?

Use VTT for web video (HTML5) and SRT for video editors. VTT supports advanced styling like colors and positioning.

Does VTT support styling?

Yes! VTT supports CSS styling for colors, fonts, positioning, and more. Customize how your captions appear on screen.

Is VTT compatible with browsers?

VTT is supported by Chrome, Firefox, Safari, Edge, and all modern browsers. It's the web standard for video captions.

Can I use VTT with video.js?

Absolutely! VTT works seamlessly with video.js, Plyr, JW Player, and other HTML5 video players.

Why Sonix

Web-ready VTT from GSM files

HTML5 Native

VTT is the web standard for captions, supported by all modern browsers.

Styleable

Apply CSS styling for colors, fonts, positioning, and more.

Precise Timing

Word-level timestamps ensure perfect sync with your video.

Universal Support

Works with all HTML5 video players and web platforms.

Reviews

Trusted by web developers

4.98 rating from 211 reviews

Awesome and I was really shocked when I saw how carefully my mp3 file was transcribed!!
RB
Rosalind B.
Tehran, Iran
Sonix's transcription and translation features are stunningly accurate, I'm very impressed.
CB
Constantine B.
Istanbul, Turkey
The transcription service was awesome. I can’t thank Sonix enough.
GI
Glenda I.
San Diego, CA USA
The UI is da bomb with so many great features including the one where I can highlight a passage and download as a clip. So very useful! It’s editing and transcription combined!!
SG
Steve G.
Sammamish, Washington
I have tested your product among others, and I have to say, Sonix provides the best results, a really great product!!!
DB
Dan B.
London, Ontario, Canada
I was especially impressed with the quality when it comes to other accents as most other companies can only give a good machine transcript if it is a US accent. Sonix is amazing and I have ...
PS
Preethi S.
Hyderabad, India
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