How to Contribute

We'd love to accept your patches and contributions to this project. There are just a few small guidelines you need to follow.

Contributor License Agreement

Contributions to this project must be accompanied by a Contributor License Agreement. You (or your employer) retain the copyright to your contribution; this simply gives us permission to use and redistribute your contributions as part of the project. Head over to to see your current agreements on file or to sign a new one.

You generally only need to submit a CLA once, so if you‘ve already submitted one (even if it was for a different project), you probably don’t need to do it again.

Code reviews

All submissions, including submissions by project members, require review. We use a Gerrit instance hosted at for this purpose.

Sending patches

The basic git workflow for modifying libwebp code and sending for review is:

  1. Get the latest version of the repository locally:

    git clone && cd libwebp
  2. Copy the commit-msg script into ./git/hooks (this will add an ID to all of your commits):

    curl -Lo .git/hooks/commit-msg && chmod u+x .git/hooks/commit-msg
  3. Modify the local copy of libwebp. Make sure the code builds successfully.

  4. Choose a short and representative commit message:

    git commit -a -m "Set commit message here"
  5. Send the patch for review:

    git push HEAD:refs/for/main

    Go to to view your patch and request a review from the maintainers.

See the WebM Project page for additional details.

Code Style

The C code style is based on the Google C++ Style Guide and clang-format --style=Google, though this project doesn't use the tool to enforce the formatting.

CMake files are formatted with cmake-format. cmake-format -i can be used to format individual files, it will use the settings from

Community Guidelines

This project follows Google's Open Source Community Guidelines.