OpenWV is a free and open-source reimplementation of Google's Widevine Content Decryption Module (CDM), the portion of the Widevine DRM system that runs in your browser, obtains content keys for protected media, and decrypts the media using those keys. OpenWV is a drop-in replacement for Google's official, proprietary CDM and implements the same shared library API.

OpenWV does not come with a device identity and will not work without one. A device identity, typically stored as a .wvd file, contains metadata about a Widevine client as well as a private key that authenticates that client to Widevine license servers. Some license servers return different sets of content keys to different clients: for example, many content providers encrypt high-definition content with a separate key and only give that key to device identities from hardware-backed ("L1") CDMs. If you want to use OpenWV, you must obtain an appropriate .wvd file yourself and include it in the build as described below.

Compilation

Because CDM libraries are heavily sandboxed by browsers, OpenWV cannot read configuration from disk at runtime. That means that all configuration, including the device identity mentioned above, must be present at build-time. As such, there are no official precompiled binaries: the only way to use OpenWV is to build it yourself.

To build OpenWV, follow these steps:

1. Make sure that Git, Rust, and Clang are installed on your system. (To install Clang on Windows 10/11, run winget install LLVM.LLVM.)
2. Clone this repository and its submodule, telling Git to keep the two in sync: git clone --recurse-submodules -c submodule.recurse=true https://github.com/tchebb/openwv.git
3. Place your .wvd file in the project root (alongside this README) and name it embedded.wvd. You may set other configuration options as desired by editing the CONFIG variable in src/config.rs.
4. Build the library: cargo build --release
5. Find the built library in target/release/. Depending on your OS, it will be named libwidevinecdm.so, widevinecdm.dll, or libwidevinecdm.dylib.

Installation

NOTE: In these instructions, "the OpenWV library" means the library you built in the last section—libwidevinecdm.so on Linux, widevinecdm.dll on Windows, or libwidevinecdm.dylib on macOS.

Firefox

1. Open about:support and note your "Profile Directory".
2. Open about:config. Set media.gmp-widevinecdm.autoupdate to false (creating it if needed), and set media.gmp-widevinecdm.version to openwv (or to another name for the directory you'll create in step 4).
3. Navigate to gmp-widevinecdm/ within your profile directory.
4. Create a subdirectory named openwv and place the OpenWV library and manifest-firefox.json, renamed to manifest.json, inside it. Note that you must use OpenWV's manifest.json instead of Google's, as Firefox will not play video if we falsely advertise decoding support.

If you manually check for addon updates, Firefox will replace OpenWV with Google's CDM. The media.gmp-widevinecdm.autoupdate setting prevents automatic updates, but there's no way to prevent manual updates. If this happens, set media.gmp-widevinecdm.version back to openwv—no need to repeat the other steps.

Chrome/Chromium

1. Open chrome://version/ and note the parent directory of your "Profile Path". This is Chrome's "User Data Directory".
2. Navigate to WidevineCdm/ within the User Data Directory.
3. If there are any existing subdirectories, delete them.
4. Create a subdirectory named 9999 (or any numeric version greater than that of Google's CDM), and place OpenWV's manifest-chromium.json, renamed to manifest.json, inside it.
5. Beside manifest.json, create a directory named _platform_specific with a directory named {linux,win,mac}_{x86,x64,arm,arm64}, as appropriate, inside it. For example, _platform_specific/linux_x64/ on 64-bit Intel Linux. Place the OpenWV library in this innermost directory.
6. On Linux only, launch and quit the browser once before playing any Widevine-protected media. OpenWV will not be loaded on the first launch due to an implementation quirk of Chromium.

Kodi (via InputStream Adaptive)

1. Build OpenWV with encrypt_client_id: EncryptClientId::Never, as Kodi cannot handle service certificate request messages as of this writing (InputStream Adaptive v21.5.10).
2. In Kodi, navigate to "Add-ons > My add-ons > VideoPlayer InputStream > InputStream Adaptive" and select "Configure".
3. Ensure the settings level (the gear icon) is set to at least "Advanced".
4. In the "Expert" tab, set "Decrypter path" to the directory where you've put the OpenWV library. Don't include the library name itself.

References

The APIs, algorithms, and data types used in OpenWV were gathered from a variety of official and unofficial sources:

• API headers (third-party/cdm/) come from the Chromium source.
• Widevine protobuf definitions (third-party/widevine_protos.pb) were extracted from chromecast_oss/chromium/src/out_chromecast_steak/release/pyproto/ in Google's Chromecast Ultra v1.42 source drop.
• The .wvd format and many algorithmic details come from the pywidevine project.