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 55+ 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 54+ languages from your original video.
More ways to work with FLV files
Other FLV conversions
Trusted by video creators
I'm fully going to recommend Sonix to everyone! Most people are going to be blown away!
I am thrilled with the level of accuracy and the easy if which I am able to listen to and adjust the transcript. It’s very user friendly.
I wouldn't have been able to pass my course without this technology. I was able to get two A's thanks to this program!
Thank you for all of your help with my dissertation!!! Ya'll rock!!
I LOVE Sonix. It's saving my life. I'm working on a project with almost NO budget, interviewing a bunch of people and the Sonix transcriptions are accurate, and are so easy and int...
I loved my experience cause Sonix has a really good tutorial and it got the words from the audio pretty well. It really did it what I needed really fast, even if it was the first t...
Sonix is AWESOME and extremely accurate. This software has it all. I wish that all of the software that I use on a daily basis had the complete and thoughtfully created functionali...
Content is still king. Google can’t crawl audio from webinars and videos. Getting that content transcribed with Sonix is an absolute must if you want to drive more leads to your web site.
Add subtitles to FLV now
Try Sonix free with 30 minutes of transcription. No credit card required.
