Some sink elements have a "sync" property that if you set it to false will dramatically improve the latency. My version of GStreamer doesn't have any of the gtk sinks so I don't know if they have it or not, but autovideosink does so you could test with that.
From: Emmanuel Pacaud <[hidden email]> To: Discussion of the development of and with GStreamer <[hidden email]> Sent: Wednesday, April 19, 2017 6:47 AM Subject: low latency appsrc pipeline
In a camera video viewer I'm developping, I'm trying to achiveve the
lowest latency possible for the video output.
The pipeline I'm using is based on appsrc, do some color conversion,
then display the output with gtksink or gtkglsink.
What I would like is a pipeline that displays the frames as they are
acquired from the camera. What would be the best way to achieve this
Currently, for some unkwnon reason, there is sometime around 1 second