Trim Video
Cut clips with stream-copy or re-encode - drag & drop studio powered by ffmpeg.wasm.
OpenTranscribe video in your browser with Whisper and export SRT/VTT in multiple languages. Optional OpenAI or Groq key for faster results. - runs entirely in your browser. Free, fast and private.
MP4, WebM, MOV, MKV, MP3 or WAV - processed in this tab, nothing uploaded to OneDevToolkit.
Set the spoken language and output languages. Local Whisper is default; paste your own OpenAI or Groq key for faster results.
Audio is extracted at 16 kHz, then transcribed with timed cues. Keep this tab open until files are ready.
Edit cues if needed, then save subtitles per language - or a ZIP of every file.
Video Subtitle Generator transcribes speech from a video or audio file in this browser tab. Local Whisper is the default. If you paste your own OpenAI or Groq key, audio goes only to that provider - never to OneDevToolkit servers.
Drop a clip, pick the spoken language and the subtitle languages you need, then generate SRT and VTT files. Short clips work fully offline after the Whisper model downloads once. Longer or multi-language jobs are faster with your own API key. Edit cues before you download.
Processes data instantly with no server round-trips.
Your data never leaves your browser. Nothing is uploaded.
Works in any modern browser. Nothing to download or install.
No limits, no sign-up, no credit card required.
Works on desktop, tablet and mobile devices.
Beautiful in both themes. Your preference is saved.
Keyboard shortcut
Run Video Subtitle Generator on local files when you cannot upload client or work documents.
Process deliverables on-device and keep an audit trail with privacy receipts where supported.
Handle common video & audio tasks without installing desktop software.
Answers for this tool. For site-wide help, open the FAQ hub.
No. The file stays in this tab. Local mode never sends audio anywhere. Optional API mode sends audio from your browser to OpenAI or Groq using your key only.
On-device translation models are too large for a casual browser tool. Without a key you still get subtitles in the spoken language. Add your OpenAI or Groq key to translate cues into other languages.
Local Whisper is best under about 15 minutes and 250 MB. Longer files should use your own API key, or trim the clip first.
Video tools use ffmpeg.wasm in your browser after the engine loads. Your clip is processed locally - it is not uploaded to OneDevToolkit for conversion.
The first run downloads the FFmpeg WebAssembly engine (~30 MB). Later runs reuse the browser cache and start faster.
Common inputs include MP4, WebM, MOV, and MKV. Exact support depends on what your browser can demux and what FFmpeg can decode in-wasm.
Stream copy needs compatible codecs/keyframes. Switch to re-encode for frame-accurate cuts or mixed sources - Video Subtitle Generator often retries automatically.
Shorter clips are safer in-browser. Very long 4K files may exhaust memory. Trim first if jobs fail or the tab freezes.
Most modes let you keep or drop audio. Check the Options panel before processing.
Yes for short clips. Prefer Wi-Fi for the first FFmpeg download and avoid huge phone recordings when possible.
Lower resolution, stronger compression, or shorter duration reduces size. The success banner shows before/after size when available.
OneDevToolkit does not add watermarks to Video Subtitle Generator outputs.