Step 1
Upload video
Upload your FLV video file to Sonix and select the language.
Add subtitles to FLV videos
Sonix automatically transcribes your FLV video and lets you add professional subtitles with customizable styling.
Auto-transcribe
Custom styling
Burn-in option
Audio
Video
DOCX
SRT/VTT
PDF
53+ Languages
10x
Faster than real-time
Add subtitles to FLV in minutes
99%
Accuracy rate
Industry-leading AI transcription
53+
Languages
Subtitles in any language
Custom
Styling
Fonts, colors, positioning
Add subtitles to FLV in 4 steps
Step 2
Auto-transcribe
Sonix AI transcribes your video with word-level timestamps.
Step 3
Customize subtitles
Split subtitles, adjust timing, and customize fonts and colors.
Step 4
Export or burn-in
Download SRT/VTT files or burn subtitles directly into your video.
Everything about adding FLV subtitles
Can Sonix add subtitles to FLV videos?
Yes! Upload your FLV video, and Sonix will transcribe it and let you add professional subtitles with customizable styling.
Can I burn subtitles into the video?
Yes! Sonix can permanently embed (burn-in) subtitles into your FLV video with your choice of fonts, colors, and positioning.
What subtitle styles are available?
Customize fonts, colors, background boxes, positioning (top, center, bottom), and more for your burned-in subtitles.
Can I download subtitle files separately?
Yes! Export subtitles as SRT, VTT, or other formats to use with YouTube, Vimeo, or your video editor.
Can I translate subtitles to other languages?
Absolutely! Sonix can translate your subtitles into 54+ languages for multilingual videos.
How do I split subtitles correctly?
Sonix offers auto-split options for max characters per line, lines per caption, and max duration. Fine-tune manually if needed.
The easiest way to add video subtitles
Auto-Transcribe
Upload your FLV and get accurate subtitles automatically.
Custom Styling
Choose fonts, colors, and positioning for professional results.
Burn-in Option
Permanently embed subtitles into your video with one click.
Translate
Create subtitles in 53+ languages from your original video.
More ways to work with FLV files
Other FLV conversions
Trusted by video creators
What I loved about the transcription is that it is fast and it's also highly accurate.
You guys were SO easy to use. Competitors made my life so complicated but you guys were a breeze to work with!
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I was cleaning up the transcription of the recording of my Brazilian client. Sonix did a surprisingly good job. Sonix's accuracy in transcription is great.
I thought it was absolutely amazing, flawless.
I absolutely loved how well the software was able to distinguish between individual speakers. Exceptional product and well-polished.
Sonix is faster and better than YouTube at making captions for my videos!
I need to produce very accurate transcripts and the initial transcripts Sonix produces are much better than competitors (I've used many others).
Add subtitles to FLV now
Try Sonix free with 30 minutes of transcription. No credit card required.
