Ethernet camera performance significantly degraded in version 1.14

I have a simple pipeline to display an ethernet camera using the NXP IMX6d chip. In Gstreamer version 1.8.3, the video is nice and smooth. But in version 1.14, the video becomes very jerky.

Of course the pipeline is in code but in a gst-launch command line, it would be udpsrc port=<port_num> ! application/x-rtp media=video,clock-rate=90000,encoding-name=H264,payload=96 ! rtph264depay ! h264parse ! imxvpudec ! imxipuvideosink framebuffer=<device_name>.

To isolate the problem I inserted a bufferprobe on each source pad and found that on the src pad of the decoder I was getting the correct 30 frames/second in 1.8.3, but in 1.14 I am only getting around 9 frames per second.

After a bunch of tests, I was able to isolate the change that caused the difference in behavior: bilboed/gst-plugins-base@8bee96c4.