Using appsrc with jetpack version 4.6.3

There are samples for using appsrc:
Latency issue: nvv4l2h265enc accumulates four images before releasing the first - #3 by DaneLLL
What is maximum video encoding resolution in pixels? - #11 by DaneLLL

Please refer to them and give it a try. Please use nvv4l2h264enc and nvv4l2decoder plugins since omxh264enc and omxh264dec are deprecated.