Janne Grunau
Senior Software Engineer at Cinemo
Berlin, Germany
Summary
🤩
Rockstar🎓
Top SchoolJanne Grunau is a Senior Software Engineer based in Berlin with 26 years of hands-on experience in systems, embedded and backend engineering. He has a strong track record contributing to high-profile open-source projects—including Linux kernel subsystems, AsahiLinux for Apple Silicon, the AV1 encoder rav1e, and Google OSS-Fuzz—often working on low-level performance, build systems, and hardware integration. At Cinemo he continues to apply deep expertise in media processing and kernel-level device support, building on prior freelance work that spanned diverse platforms. Janne’s background in bioinformatics gives him a distinctive systems-thinking approach to complex problems, and his contributions range from ARM/assembly optimizations to USB, SPI and power-management support for modern SoCs. Colleagues rely on him for robust, portable solutions that bridge bootloaders, kernel drivers and user-space media stacks.
26 years of coding experience
5 years of employment as a software developer
Bachelor of Science (BSc), Bioinformatics, Bachelor of Science (BSc), Bioinformatics at Freie Universität Berlin
Github Skills (65)
deco10
python10
mpeg2-ts10
bash10
spi10
device-driver10
build-automation10
boot10
arm10
embedded10
fuzzer10
bootloader10
iommu10
apple-silicon10
encoder10
Programming languages (14)
Github contributions (5)
MythTV/mythtv
May 2002 - Dec 2010
The official MythTV repository
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1136 commits in 8 years 8 months
Contributions summary:Janne contributed to the MythTV project by fixing bugs and optimizing code related to audio decoding, subtitle handling, and MPEG-TS stream processing. Their work included improvements to the H.264 decoder, the addition of AAC/LATM parsing and decoding capabilities, and enhancing the handling of DVB subtitles. They also addressed playback issues, such as those related to frame count in H.264 streams and seeking in the audio decoder.
mythtv
AsahiLinux/m1n1
Feb 2021 - Jan 2023
A bootloader and experimentation playground for Apple Silicon
Role in this project:Back-end Developer & System Architect
Back-end Developer & System ArchitectContributions:79 reviews, 120 commits, 113 PRs in 1 year 11 months
Contributions summary:Janne's contributions primarily focused on enhancing the `asahilinux/m1n1` bootloader project for Apple Silicon devices. They implemented features such as setting boot arguments, support for XZ compression for kernel payloads, and integrating the use of argparse and pathlib for improved code structure. Furthermore, the user made significant contributions to the USB subsystem, adding a second CDC ACM interface for virtualized UART and enhancing the handling of the TPS6598x power management IC. They also contributed to the ADT handling and MMIO tracing infrastructure for the system.
apple-siliconbootloader
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