These negotiations have been going on for many years, certainly as early as the 1997 WIPO World Symposium on Broadcasting, New Communication Technologies and Intellectual Property, in Manila, and arguably earlier. Beginning in 2017, there has been a new push to conclude the negotiations, although countries are miles apparent on substantive issues.
The 2014 KEI testimony before the House Judiciary Committee provides some historical context.
2014 KEI testimony on WIPO broadcasting treaty, to House Judiciary Subcommittee on Courts, Intellectual Property, and Internet
See in particular the 11 page written testimony.
Thiru has a timeline of WIPO negotiations on the treaty from 1961 to 2017, available here.
For more up-to-date information, see the pages for recent meetings of the WIPO SCCR.