Hacking on the PipeWire GStreamer elements
Last week I attended the GStreamer Spring Hackfest in Thessaloniki. It was very nice to meet all the usual people again, as it’s been a while (I last attended a GStreamer event in 2022), and we had a great time!
What did I do there? Well, it was a great opportunity to deal with something I don’t normally do but it is quite important that someone eventually does… work on the PipeWire GStreamer elements! (yes, see what I did there?)
Pretty much anyone who has used pipewiresrc or pipewiresink in GStreamer can tell you the experience is not great. Of course you can get things done one way or another, but you can easily find yourself facing issues. The solution is often not to use those elements, at least for audio. pulsesrc and pulsesink do a great job and they are still the recommended way to access audio devices. For video, however, you need pipewiresrc to capture, and that specific scenario works relatively well, but don’t try to share a stream from pipewiresink to pipewiresrc unless you are looking for trouble.
How is it that PipeWire, of all things, does not have good GStreamer support? The truth is, these elements originate all the way back in PulseVideo… PulseVideo was the original project that was then turned into PipeWire after it was rewritten with audio and MIDI support added. The first and most important goal of this project was to allow applications to capture video from a camera, so all the focus was on that use case. And this is the use case that indeed works reasonably well until today. Everything else, including audio support, was later added without paying too much attention to detail, as things were evolving quickly, and more attention was needed in the PipeWire core, plugins, and session management.
