I just found (parts of) the code from my diploma thesis from ca. 20 years ago:D
This was a media streaming app using RTP for live audio-/video-conferencing. The code consists of a full from scratch RTP stack (C++), plus DirectShow filters. I did integrate some codecs from ffmpeg. The solution was interoperable with some unix tools and it also talked to the infamous NetMeeting. H.263 was the frequently used codec at that time with H.264 just becoming available.
I had never written any meaningful C++, COM, ATL, DirectShow filter, or Winsock code before. Didn't know about apartment states (which probably make you sound like a crazy person). This was the result.
Even though I have no idea whether the result was or is considered ok by seasoned experts in said areas, I am still super proud of the result. I started from absolute zero, got up to speed with everything and still tried to produce neat solutions along the way.
Probably (unfortunately) still to this day my most challenging project (work and pet projects). Seeing a C++ app doing audio and video streaming, processing megabytes of data with a varienty other clients without crashing or memory hogging for hours. Sweet. Even integrated some existing codecs from ffmpeg into the solution. The app was written in C#.