Ondřej Caletka
Learning And Development Systems Engineer at CSNOG
Amsterdam, North Holland, Netherlands
Summary
👤
Senior🎓
Top SchoolOndřej Caletka is a Learning and Development Systems Engineer with 14 years of experience building and operating networking services, Linux systems, and training programs from Prague to Amsterdam. A long-time open source and IPv6 enthusiast, he contributes to projects like youtube-dl (subtitle and HLS fixes) and OpenWrt packages (NAT64/tayga integration), blending practical network engineering with Python and shell development. At RIPE NCC he applies hands-on expertise in DNS, DNSSEC and TLS to learning systems, while volunteering on CSNOG and co-organising LinuxDays to bridge community education and operations. His background includes DNS and e-mail administration, IP resource management, and technical writing from a decade at CESNET, evidencing both operational depth and the ability to explain complex topics. Not obvious at first glance: he combines protocol-level fixes (ICMP/NAT64) with user-facing tooling improvements for media extraction, showing a rare mix of low-level networking and application-layer problem solving.
14 years of coding experience
9 years of employment as a software developer
Ing., Telecomunications, Ing., Telecomunications at České vysoké učení technické v Praze - ČVUT
English, tsjechisch, Dutch
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (19)
python10
feature-extraction10
scripting10
youtube-dl10
extraction10
c1110
c1710
video-download10
openwrt10
script10
subtitle10
data-extraction10
sh10
shell10
extractor10
Programming languages (14)
Github contributions (5)
openwrt/packages
Jun 2014 - Apr 2021
Community maintained packages for OpenWrt. Documentation for submitting pull requests is in CONTRIBUTING.md
Role in this project:
Back-end Developer
Back-end DeveloperContributions:21 commits, 8 PRs, 38 comments in 6 years 10 months
Contributions summary:Ondřej's commits primarily focus on enhancing the `tayga` package, which appears to be a NAT64 implementation for OpenWrt. They added and updated scripts to integrate `tayga` with netifd, the OpenWrt network interface daemon. The contributions include fixing ICMP checksum errors, adding support for static mapping, and incorporating NTP sync checks to ensure network functionality, and refactoring the aiccu package.
pull-requestsopenwrtstudio
ytdl-org/youtube-dl
Jan 2015 - Dec 2017
Command-line program to download videos from YouTube.com and other video sites
Role in this project:Back-end Developer
Back-end DeveloperContributions:6 commits, 6 PRs, 18 comments in 3 years
Contributions summary:Ondřej primarily contributed to adding and improving subtitle support for various video extractors within the youtube-dl project. Their work involved implementing closed captions for Czech Television, integrating subtitle capabilities for stream.cz, and refining the extraction logic for Playtvak videos. These changes involved modifications to Python code, specifically within the extractor modules, to fetch and process subtitle data. Furthermore, they fixed issues related to HLS playlists within ceskatelevize.
downloadervideosyoutubeyoutube-dlvideo-sites
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