Downloads and offline

Nuvio Web installs as an app and downloads titles so you can watch them without a connection: on a plane, on a train, or anywhere the Wi-Fi gives up.

#Installing the app

In Chrome, Edge and other Chromium browsers, open the profile menu and choose Install app. The item appears once the browser offers installation. The browser's own install button in the address bar works too. In Safari, use Share → Add to Dock (macOS) or Share → Add to Home Screen (iOS).

Installed, Nuvio Web opens in its own window, and it opens even with no network. The app's code is cached on the device, and a navigation that can't reach the server lands on the offline page instead of a browser error.

#Downloading a title

Open a title's sources (Select stream on its page). Every source the browser can play has a download button next to it. Pick one and it joins the queue. Each video (a movie, or one episode) gets one download.

Anything the player can play in the browser can be downloaded:

• direct files: MP4, WebM, MKV and similar, from an addon or a debrid service;
• HLS streams (.m3u8): the variant closest to your preferred quality (Settings → Playback), its separate audio track if it has one, and every segment. AES-128 encrypted streams are fine; the key is saved alongside.

What can't be downloaded, and why:

• torrents / P2P sources: the browser can't play them either;
• live streams: an HLS playlist without an end never finishes;
• DRM-protected streams (SAMPLE-AES, FairPlay, Widevine): the key can't be taken offline.

Subtitles come along too: your preferred subtitle language first, then one per other language, up to five.

#The Downloads page

Profile menu → Downloads lists this profile's downloads with their progress, and how much storage the browser allows the app. From there you can pause, resume, delete, or play.

• One at a time. Downloads queue and run in order. One download already saturates most connections, and one finished title is worth more than three half-finished ones.
• Resumable. Closing the tab pauses a download. It picks up where it left off the next time the app is open: a file continues from the bytes already saved, and an HLS download skips the segments it already has.
• Played from the device. Once a download finishes, the player uses the saved copy for that title, even online, and whichever source you picked.

#In the desktop app

The desktop app downloads to a folder on the computer instead of the browser's storage: Nuvio Web in the system's videos folder (~/Movies on macOS, %USERPROFILE%\Videos on Windows, XDG_VIDEOS_DIR, else ~/Videos, on Linux). Its built-in server does the fetching, so:

• any source with a link can be downloaded, including those only mpv plays (see Desktop); a finished one the window can't decode opens in mpv, from the file;
• there's no browser quota: the Downloads page shows the folder and its free space, and Open folder shows it in Finder, Explorer or the file manager;
• the files are ordinary files, named like a media library's: a folder per title, the video named after it (Breaking Bad S01E02.mkv, the extension its bytes say), and the subtitles beside it (Breaking Bad S01E02.en.srt), which mpv, VLC and IINA pick up on their own. An HLS copy is a playlist (… .m3u8) and its segments, which mpv, VLC and IINA open;
• downloads keep going as long as the app runs, whichever page is open, and one cut off by quitting resumes on the next launch.

While it downloads, the video is media; it takes its name once it is complete, so nothing half-downloaded looks playable. Two hidden files hold what the app needs: .nuvio.json (what the Downloads page lists) and, until it is done, .nuvio-plan.json. A second download with the same name gets a numbered folder (Heat (2)). Deleting one from the Downloads page deletes its folder. They are listed per profile, as in the browser.

#Offline

With no network, any page opens the offline page. It lists the finished downloads of the last profile used on this device and plays them in a simple player, with their subtitles, picking up where you left off. Watch progress made offline is kept on the device and sent to the server the next time the app is online.

#Where downloads live, and who sees them

Downloads are stored in the browser's private file storage for this site (the Origin Private File System). They count against the browser's storage quota for the site. The app asks the browser to keep them rather than evict them under storage pressure, but the browser has the final say.

They belong to the device, not the account. They don't sync to your other devices, and they are listed per profile. Signing out stops any download in progress and hides the downloads from the offline page, but keeps the files: they took hours to fetch, and signing back in brings them back. To free the space, delete them from the Downloads page.

#How it works

• A Web Worker does the fetching and writes to disk through synchronous file handles, so the page stays responsive during a multi-gigabyte download.
• It tries each source directly first. If the host sends no CORS headers, or the source is plain http: under an https: app, it falls back to the instance's download proxy (/api/downloads/proxy). The proxy only serves signed-in users, refuses private and internal addresses, and streams bytes through without keeping them. See Security.
• The service worker serves saved files at /offline-media/<id>/…, with range support so the video can seek, and x-content-type-options: nosniff. A direct file keeps the source's content type only when it is audio or video (or an HLS / MP4 application type); anything else is served as video/mp4, so a source can't plant an HTML page on the app's origin. The player plays a download through that URL, the same way as any other source.