It's been a while I haven't used EXT-X-START, but enabling it on a live stream recently, I noticed that it works in some third-party players and iOS, but not Quicktime 10.4 and tvOS. Am I doing something wrong here ?
Here is a test stream
http://www.djing.com/tv/a-05.m3u8
Line for EXT-X-START
#EXT-X-START:TIME-OFFSET=0.0
