Frame Input Serially or Latest one

How does deepstream take frame input? Is it serially or takes the latest one?
If a camera takes 30 frames per second and let assume to process 20 frames it takes more than one second. What will deepstream do? Will it wait for 21st frame(serially) or it will take the latest frame taken by the camera?

It will depend on how the rtspsrc is configured, if drop-on-latency property is true, then it will drop frames, and it will also depend on what latency property is set on rtspsrc bin from when it will start dropping the frames