Capture Studio 作者： Chiva

Capture Studio is a full capture toolkit for Firefox. Take a screenshot, record
your screen or camera, download a video, read what was said in it, mark it up,
and keep the result — without a single one of those steps going through a server
somewhere.

Formerly published as "Capture & ScreenShare".

SCREENSHOTS

• Visible area — capture what is on screen right now. Ctrl+Alt+V
• Selected area — drag a rectangle and capture only that. Ctrl+Alt+A
• Full page — the whole scrollable page, scrolled and stitched into one tall
image. Ctrl+Alt+F
• Timed capture — a 3, 5 or 10 second countdown shown on the page, for menus
and hover states that vanish the moment you click elsewhere. Ctrl+Alt+C
• Annotate an image you already have — open one from your computer or paste it
from the clipboard. Ctrl+Alt+E

Every capture opens straight in the editor.

RECORDING

• Screen — record a display, a window or a tab, with system sound and your
microphone if you want them.
• Camera — record your webcam, with or without the microphone.

Both save as .webm.

THE IMAGE EDITOR

Pen, highlighter, line, arrow, rectangle, ellipse and text, each on a single
key. Erase back to the original picture. Hold Shift to snap a shape straight.

Annotations are objects rather than baked-in pixels: click one to move, resize
or delete it, and undo steps back through what you drew rather than through
frames. Text has a full bar of its own — a searchable font list including
Google Fonts, size, bold, italic, underline, strikethrough, colour, highlight
and alignment.

• Crop, with arrow keys to nudge the frame a pixel at a time.
• Split one capture into many. Add columns and rows, drag any line inside the
frame to size the pieces, and save every cell as its own PNG — numbered so a
twelve-way split sorts back into the order it was cut.
• Convert a picture to Canvas 2D drawing code. The image is reduced to a few
colours and its boundaries traced into outlines, and what comes out is a
drawCapture(ctx) function of moveTo, lineTo and fill. The bitmap is not in
the output — this is a conversion, not a canvas wrapped around a data: URL.

Finish with Download, Copy, or Upload to Google Drive.

VIDEO DOWNLOAD

• A Download button on the YouTube page itself, in the row beside Like and
Share, offering only the resolutions the video actually has — each with an
estimated size — plus audio-only as MP3, M4A or Opus.
• YouTube and roughly two thousand other sites. Paste an address or open the
page and press Ctrl+Alt+D. Pick a quality up to 4K, a container, or audio
only as MP3, M4A, Opus, FLAC or WAV. Subtitles can be fetched, including
auto-generated ones, and burned into the file. Playlists come down as a
numbered folder.
• A format table when you want to be exact — every stream with its resolution,
frame rate, codecs, size, and whether it carries sound at all. Click a row to
take that exact stream; a video-only stream is paired with the best audio and
merged.
• It finds what a page is playing even when the page will not say. A modern
player hands its <video> a blob: URL and feeds it segments, so the document
knows nothing; the downloader also lists every media response seen on the
tab, HLS and DASH manifests included.
• Downloads outlive the tab. The queue lives in the helper, not the page —
close the downloader mid-download and reopen it, and the job is still there.
• Progress says which part it is on: Video, then Audio, then Merging — rather
than a bar that reaches 100% and starts again.
• "Use my Firefox cookies" downloads as your signed-in session, for sites that
need it. Off by default.

Please read REQUIREMENTS below: full download support needs a small helper
program installed separately.

TRANSCRIPTS

Press Transcript under a YouTube video, or Ctrl+Alt+T on any page, and what was
said opens as a note.

• Every paragraph links back into the video at the second it was spoken, so
finding the sentence and watching the person say it are the same action.
• Captions are not prose, and turning them into prose is most of the work here.
They arrive as thousands of fragments cut where the line on screen had to
break, and machine-made ones repeat the tail of each fragment to make the
words roll upward. Those repeats are removed and the fragments regrouped into
paragraphs at pauses and sentence ends. What comes out reads as writing.
• Or as a table — time in one column, words in the other — which you can
annotate in place with a column of your own notes.
• Copy it in the shape you need: plain text, text with timestamps, Markdown
table, Markdown note, SubRip .srt or WebVTT .vtt.
• Languages are sorted so the useful one is at the top: written-by-a-person
above machine-generated, the spoken language above translations of it, and
the spoken track marked.

These are the video's own captions. There is no speech recognition here, no API
key and no service in the middle — so a video with no captions has no
transcript, and it says so rather than offering to make one.

NOTES

A Markdown editor built on blocks: headings, lists, to-dos, quotes, callouts,
tables, code, diagrams and dividers, with a selection toolbar and a "/" menu.
What it saves is plain Markdown — a .md file any other program can open.

• Read a web page as a note. Give it a URL and it keeps the article and leaves
the navigation, banners and promos behind, using Mozilla's Readability — the
same engine as Firefox's own Reader Mode. Nothing on the page runs: the HTML
is parsed in a document that is never attached to anything, and scripts are
stripped before the extractor sees it.
• Browse your Drive as a tree, and open a folder as a tab with its own address
bar and listing, the way a folder opens in a file manager.
• Drag the columns to resize them, or fold the file list away entirely. The
widths are remembered.
• A .json file opens in a read-only viewer, re-indented and syntax coloured.
• Rename, move, bin and restore, with a searchable folder picker.

GOOGLE DRIVE (OPTIONAL)

Sign in and captures, recordings, transcripts and notes can be saved to your
own Drive. Several accounts can be signed in at once, each appearing as its own
branch with its own storage total and its own root folder — the place that
account starts and where its new files go.

The file list shows Markdown, text and JSON files, and folders. Nothing else in
your Drive appears: not PDFs, not images, and none of Google's own Docs, Sheets
or Slides.

Drive is entirely optional. Everything above works signed out.

PRIVACY

Captures, recordings and transcripts are held on your own machine in the
browser's storage. They leave it only when you press Upload, and only to your
own Google Drive.

There is no developer server, no account with us, no analytics and no
telemetry. The only addresses this add-on contacts are Google's, for a Drive
upload you asked for, and the video's own site when reading its captions.

REQUIREMENTS

• Firefox 140 or later on desktop; Firefox 142 or later on Android.
• Video download beyond plain, directly-fetchable files needs a small helper
program — a native messaging host built on yt-dlp and ffmpeg, installed
separately and running only on your machine. Without it the downloader still
works for simple files and tells you plainly that it is doing the lesser
thing. Setup instructions are in the project README.

KEYBOARD SHORTCUTS

Ctrl+Alt+V capture the visible area
Ctrl+Alt+A capture a selected area
Ctrl+Alt+F capture the full page
Ctrl+Alt+C capture after a countdown
Ctrl+Alt+E open the editor
Ctrl+Alt+D download video from this page
Ctrl+Alt+T transcribe the video on this page