Etienne Dechamps

Also known as: dechamps, edechamps, e-t172

I am a software engineer with ~20 years experience (~10 years professionally) specializing in backend/systems programming targetting Linux and Windows. I also like to spend my time on pet projects related to audio and video playback (e.g. calibration, signal processing), and a bunch of other things.

My primary language is C++, but I also dabble in Python especially for data crunching and signal processing projects. I'd love to write some Rust one day.

This is my personal profile describing projects I do on my free time. I am also employed as a software engineer by Google, but none of the activity under this GitHub profile is affiliated to my employer in any way. My GitHub activity on behalf of my employer can be found under the edechamps-Google profile.

Active projects

• FlexASIO, a universal ASIO driver (C++, Windows, audio)
  • By far the project I'm most known for, with 1k+ GitHub stars and a Wikipedia mention.
• ASIO401, an ASIO driver for the QA403 industrial-grade audio analyzer and earlier versions (C++, Windows, USB, audio)
  • Directly implementing a bespoke USB protocol using WinUSB.
  • Developed with the support and blessing of the manufacturer.
• videojitter, a physical light-based video frame presentation timing measurement system (Python, video, signal processing)
  • The first tool of its kind, as far as I'm aware.
• transmission_delete_unwanted, a tool for removing files from Transmission torrents (Python)

Inactive projects

• Loudspeaker Explorer, a loudspeaker measurement visualization, analysis and comparison tool (Python, Jupyter, data visualization, audio)
  • Ever wondered what would happen if someone crammed an entire app into a single Jupyter notebook and ran the entire thing off Colab? Now you know.
• RudeWindowFixer, a tool to fix Windows always-on-top taskbar issues (C, Windows, binary reverse engineering)
  • My first foray into binary reverse engineering, reversing closed-source Windows explorer binaries related to taskbar operation and using my findings to work around a particularly annoying bug Microsoft hasn't bothered to fix in many years.
• WindowInvestigator, a set of Windows window management introspection tools (C, Windows)
  • I wrote these to help with the investigation that led to RudeWindowFixer.
• WinSoftVol, a Windows driver to force software volume control (C, Windows, kernel-mode driver)
  • My first foray into Windows driver development.
  • This trivial filter driver alters the way Windows audio devices work, preventing Windows from using hardware volume control.
• kmlpipe, a geographic data processing toolbox (bash, XSLT, GIS)
  • I wrote this to assist me in my search for the perfect London flat.
  • It's a geographical information system using XML files as its internal representation (I'm sorry), with individual processing steps written in XSLT (I'm very sorry), with the whole thing orchestrated by a pile of shell scripts (I am so, so sorry). It also integrates with various APIs like Google Maps.
    • Needless to say, if you're planning to use this, you are either very brave, foolish, or both.
• AudioMeterEvent, a tool to automatically call an HTTP API when a Windows audio device is in use (C#, Windows, audio)
  • My first foray into C#.
  • I use this for home automation, to automatically turn my speakers on/off based on audio activity.
• LGTVDeviceListener, an LG TV remote control tool triggered by Windows USB device plug/unplug events (C++, Windows)
  • What do you mean, "niche"?
• laplock, a tool to automatically lock a Windows laptop when its lid is closed (C, Windows)
  • One of these "I can't believe Windows doesn't have that built in" workarounds
  • My oldest project on GitHub: initial release was in 2013. It still works and I still use it to this day!
• APO, a bunch of random docs on Windows APOs (Windows, audio)
• audiotools, a disparate set of docs and tools for audio measurement (audio)
  • Includes discussions of some of the relevant IEC and AES standards.
• HDRCompare, a set of filters to compare SDR vs. HDR video files (ffmpeg, video)
• WinIPBroadcast, a tool to send network broadcasts to all Windows network interfaces (C, Windows, networking)
  • Another decade-old tool, which (as far as I know) still works to this day.
  • I wrote it to get old LAN games to work. Not nearly as useful nowadays.

Projects I've significantly contributed to

• tinc, a peer-to-peer mesh VPN (C, networking)
  • Made major contributions to the modern tinc 1.1 protocol (SPTPS), including redesigning the way it does NAT traversal (UDP hole punching, etc.) and MTU probing.
• ZFS On Linux, a feature-rich filesystem (C, Linux, kernel)
  • My first foray into Linux kernel development.
  • Made a number of non-trivial contributions, mostly related to performance and scalability, on behalf of my employer at the time, OVH.