decklink: Black screen when grabbing 1080p30 from decklink intensity pro 4K

Submitted by sylvain cormier

Link to original bug (#752028)

Description

Created attachment 306940
GST_DEBUG=*:6

gst-launch-1.0 decklinkvideosrc mode = 10 connection= 2 ! xvimagesink
gives black screen.

Attachment 306940, "GST_DEBUG=*:6":
GstreamerLog.txt.tar.gz

Version: 1.5.2