DownloadHelper CoApp 2.0.20

Video DownloadHelper CoApp Overview

Video DownloadHelper CoApp is the companion application for the Video DownloadHelper browser add-on. Some operations the add-on requires cannot be carried out from inside the browser, so the add-on calls this external application transparently when needed.

Installation and Platform Support

The CoApp is available for Windows, macOS, and Linux, with 32-bit and 64-bit Linux builds. The installation method depends on the platform.

• Windows: The user downloads the installer, runs it by double-clicking the file, and follows the on-screen instructions.
• macOS: A pkg file is the recommended method. A DMG image is also offered, in which case the application is dragged to a chosen location and then installed with a terminal command, either for the current user or system-wide.
• Linux: Debian and Ubuntu users can install a .deb package. Other distributions use a tar.gz archive that requires an additional step to complete the installation. A user-wide installation extracts the archive into the home directory, while a system-wide installation extracts it into /opt with administrator rights.

Each download is listed with a SHA256 checksum, which allows users to verify the file before installing it. Linux builds are published for several glibc versions, including 2.23, 2.27, and 2.31.

Core Functions

The CoApp handles tasks that a browser extension cannot perform on its own.

• File writing: Browser add-ons cannot write large files such as videos directly. The downloads API transfers data from a URL verbatim, which is unsuitable for files generated by the add-on. Writing files through the CoApp is also required for HLS and DASH streams.
• Media conversion: The application includes a build of the ffmpeg video converter. It creates combined audio and video files when the two streams are delivered separately, and it performs conversion operations on downloaded media. Firefox users previously had to install a separate converter for these tasks, and conversion was not supported in other browsers.
• Background operation: The add-on calls the application whenever an operation requires it, so users generally do not interact with the CoApp directly.
• Native messaging: Communication takes place through the Native Messaging Protocol, which ensures the application cannot be launched by other add-ons.

Security and Source Code

The companion app uses the Native Messaging Protocol, and its full source code is released as open source on GitHub. Public access to the code allows independent review of its behavior.

Release Status

The latest release on GitHub is version 2.0.19, published on 19 February. The repository was archived by its owner on December 15, 2025, and is now read-only.

Usability

After installation, the CoApp requires no configuration, since the add-on manages when it is called. Windows and macOS pkg installations involve a single installer, while Linux users who choose the tar.gz archive must complete extra steps and may prefer the terminal instructions provided for user-wide or system-wide installs.