For the youtube urls that VLC 2.2.4 on OS X can play, VLCKit can't play. I saw the following in the output console:
2016-10-07 21:27:51.412910 App[13086:868188] [] nw_host_stats_add_src recv too small, received 24, expected 28
2016-10-07 21:27:51.413454 App[13086:868188] [] sa_dst_src_lookup send failed: [65] No route to host
2016-10-07 21:27:51.414426 App[13086:868188] [] nw_host_stats_add_src received non-critical error for SRC_ADDED: [2] No such file or directory
2016-10-07 21:27:51.414895 App[13086:868188] [] sa_dst_compare_rfc6724 Rule 1, prefer d1, d2 is not routable
2016-10-07 21:27:51.415383 App[13086:868188] [] sa_dst_compare_internal 172.217.4.142:443@0 > 2607:f8b0:4007:808::200e.443@0
2016-10-07 21:27:52.259880 App[13086:868206] [] sa_dst_compare_rfc6724 Rule 1, prefer d1, d2 is not routable
2016-10-07 21:27:52.260349 App[13086:868206] [] sa_dst_compare_internal 172.217.4.142:443@0 > 2607:f8b0:4007:808::200e.443@0
State changed to Stopped <-- (logged by my app: the VLCMediaPlayer instance changed its state to "stopped.")