RTSP from Uniview cameras won't play on iPhone

[kmax1940]

I am using FFMPEG to take the RTSP from uniview cameras and turn it into HLS.

When I encode the rtsp to libx264 it will play on iPhones.
BUT...
When I copy the rtsp rather than encoding it... it won't play on iPhones. I just plays black.

This is ONLY with uniview.... with all other manufacturers I have tried this with it works fine on iPhones.

Any ideas?

 

[kmax1940]

If I use
"-c:v libx264" it works on iPhone

If I use
"-c:v copy" it does not play on iPhone. It just flashes the first picture or either just plays black screen.