Windows Screen Recorder Development

I need a Windows compatible screen recording software that captures video with audio and saves it as an mp4.

Key Features:
- The software should record audio along with the screen video.
- The primary use of these recordings is for troubleshooting or support, so reliability and clarity are key.
- Free and open source software

Ideal Skills:
- Proficient in Windows software development.
- Experienced in creating multimedia applications.
- Understands the requirements for support-focused video clarity.