Transform your FLV videos into professional subtitles in multiple formats. Make legacy Flash content accessible and modern with professional subtitles.
Legacy Flash video format for web streaming
FLV files are also known as Flash Video Files. Most FLV files use Adobe Flash Player or Adobe Air to transmit audio/video over the Internet. Most embedded videos on the Internet are FLV files, but with the introduction of HTML5 videos, many streaming services have dropped usage of FLV files. You can sometimes see FLV files with a F4V file extension. FLV files aren’t as common now, but we still support them at Sonix.
Older format - quality varies significantly
Sign up for Sonix's free trial. Includes 30 minutes free.
Upload your FLV file from your computer or cloud storage.
Choose from 53+ languages spoken in your file.
Sonix AI transcribes your FLV with word-level timestamps.
Customize line length, duration, and subtitle breaks.
Download subtitles as SRT, VTT, or other formats.
Sonix exports FLV transcriptions to all major subtitle formats: SRT (universal), VTT (web), ASS/SSA (styled), SBV (YouTube), and more.
SRT is most compatible when converting FLV to MP4 or other modern formats. Most video editors and players support SRT without issues.
Convert your FLV to MP4, export SRT from Sonix, then either upload the SRT separately to YouTube or burn subtitles into the video before uploading.
Yes! Export to ASS/SSA format for advanced styling options including custom fonts, colors, positioning, and animations.
Most social platforms require burned-in subtitles. Convert FLV to MP4, export SRT from Sonix, then use video editing software to embed them permanently.
Sonix timestamps are audio-based, ensuring accurate sync regardless of video encoding variations common in FLV files from different eras.
Export subtitles as SRT, VTT, FCPXML, and more for any platform.
Control line length, duration, and style of your subtitles.
Create subtitles in 53+ languages from your original audio.
Permanently embed subtitles into your video with one click.
Sonix is the best transcription program I have worked with.
One of the best sites/services on the Internet I've ever tried.
We love transcribing with Sonix. Your interface for subtitle editing is excellent.
It's incredibly fast, and it sets the timing for subtitles perfectly. I dread having to time everything myself, and with Sonix I can do that just by pressing Enter!
It really accelerated my work and I was amazed by the accuracy, especially given that the video featured only non-native speakers.
Of all the programs that do this, I found you the best!
Your UI and UX was one of the best I've seen. And I've seen a lot of them. Clean, simple, and pretty easy to edit.
Easy to use and it saved me SO much time transcribing.
Try Sonix free with 30 minutes of transcription. No credit card required.
AI transcription and translation in 53+ languages.
