Now I'm able to insert text into HLS streams and when I use DVBinspector to inspect the tags I can see something like "!. +g ID3.......TIT2.....Hello world.....".
However, how could I add artist/album/title... information, instead of pure text?
What's more, when I play the HLS stream with the above "hello world" ID3 tags, nothing appear on my screen. I also used VLC and check "media information". But it doesn't show anything about the ID3 tags. I can only detect the tags' existence with DVBInspector.... :(