Verbascope

Frequently asked questions

Quick answers about how Verbascope works, what it supports, and where your data lives.

What is Verbascope?

Verbascope turns any video with subtitles into a language-learning tool. Watch in the language you are learning, click words you do not know to save them in context, and review your growing vocabulary later — without ever stopping the show.

Do I need to sign up or create an account?

No. There is no sign-up and no account. Open the player and start watching.

Is my video uploaded anywhere?

No. Videos play directly from your device — nothing is uploaded. Your playback position, subtitles, and saved words are stored locally in your browser.

Which subtitle formats are supported?

You can load SRT, VTT, ASS/SSA, and TTML/EBU-TT-D subtitle files. You can also pick a subtitle track embedded inside an MKV video file.

My video has no sound — what's going on?

Verbascope plays video directly in your browser, so it can only decode what the browser itself supports. Most modern browsers handle H.264 + AAC in an MP4 container without issue. The audio tracks that commonly fail to play are:

  • AC3 / EAC3 (Dolby Digital, Dolby Digital Plus) — common in MKV rips from Blu-ray or DVD
  • DTS / DTS-HD — common in higher-quality MKV rips
  • TrueHD — Blu-ray lossless audio
  • Opus in MP4 — Safari in particular still struggles with this combination

Video codecs can also cause silent failures: HEVC/H.265 plays only on some platforms, and older VP9 / AV1 content fails on older browsers.

The fix is to convert the file (or just its audio track) to a browser-friendly codec with ffmpeg.

How do I install ffmpeg?

ffmpeg is a free command-line tool for converting video and audio.

macOS (via Homebrew):

brew install ffmpeg

Windows (via winget):

winget install Gyan.FFmpeg

Linux (Debian / Ubuntu):

sudo apt update && sudo apt install ffmpeg

Linux (Fedora):

sudo dnf install ffmpeg

Verify the install:

ffmpeg -version

How do I convert a video to a browser-friendly format?

If only the audio is the problem (e.g. AC3 or DTS), keep the video stream as-is and re-encode just the audio to AAC. This is fast because the video is copied without re-compression:

ffmpeg -i input.mkv -c:v copy -c:a aac -b:a 192k output.mp4

If the video codec is also unsupported (e.g. HEVC), re-encode both streams to H.264 + AAC:

ffmpeg -i input.mkv -c:v libx264 -preset medium -crf 20 -c:a aac -b:a 192k output.mp4

For files with multiple audio tracks, pick the one you want with -map:

ffmpeg -i input.mkv -map 0:v:0 -map 0:a:1 -c:v copy -c:a aac -b:a 192k output.mp4

-map 0:a:1 selects the second audio track from the first input. Use ffmpeg -i input.mkv on its own first to list the tracks.

How do I extract subtitles from a video file?

If your video has embedded subtitle tracks (typical for MKV files), you can pull each one out into its own .srt file. List the tracks first:

ffmpeg -i input.mkv

Look for lines like Stream #0:2(eng): Subtitle: subrip — the 0:2 is what you reference next. Extract that track to SRT:

ffmpeg -i input.mkv -map 0:2 -c:s srt subs.eng.srt

For text-based subtitles already in subrip (SRT) format, you can copy without re-encoding:

ffmpeg -i input.mkv -map 0:s:0 -c:s copy subs.srt

Bitmap subtitles (hdmv_pgs_subtitle, dvd_subtitle) are image-based and cannot be converted to SRT by ffmpeg alone — you would need an OCR tool such as SubtitleEdit to convert them to text.

How do I save vocabulary while watching?

Click any word in the currently displayed subtitle line. The word is saved together with the sentence it appeared in, so you keep the context. Saved words show up in the right-hand panel and are remembered per video.

Can I export my saved words?

Yes. Open the Tools popup in the right-hand panel and export your selections to CSV. Import the file into Anki, a spreadsheet, or any other tool you use for review.

What if I only have subtitles in one language?

You can generate a machine translation directly inside the player. Pick a target language and Verbascope streams the translation back as a second subtitle track.

How does the A–B loop work?

Set an in-point (A) and an out-point (B) and the player will replay that segment until you turn the loop off. Combine it with the playback-speed buttons to slow tricky lines down.

Will my progress be there next time I open the video?

Yes. Verbascope remembers playback position, both subtitle tracks, and your saved words per video. Up to five recent videos are kept; older ones are evicted automatically.

Can I watch with dual subtitles on my TV?

Yes. Use the Tools popup to export both tracks merged into a single colour-coded ASS file. Drop it next to the video file on a USB stick or media server and your TV will show original and translated subtitles together.

Which browsers does Verbascope work in?

Any modern browser with HTML5 video support. For drag-and-drop folder access, a Chromium-based browser (Chrome, Edge, Brave) gives the smoothest experience via the File System Access API.

Does Verbascope cost anything?

No. Verbascope is free and runs entirely in your browser.

Still curious? Open the player and try it on a video you already love.