Handling HTML5 Video for iOS and Safari clients

[Leon]

Branch: varnish-5.1.2
Config: mostly default

Dear List,

there are a lot of stuff in the results of common search engines concerning 
streaming mp4 files via varnish. But my mental picture is still unsharp. Therefore 
following questions; It seems that Safari-Browser has still a problem with such 
assets. I had tried two approaches: 

1st: Just "pass" it to the backend:

 vcl_recv : if ( req.url ~ "\.(mp4|webm)$" ) { return(pipe); }

or

2nd: Deliver it directly 

 vcl_recv             : if ( req.url ~ "\.(mp4|webm)$" ) { unset req.http.cookie; }
 vcl_backend_response : if ( bereq.url ~ "\.(mp4|webm)$" ) { set beresp.do_stream = true; }


Both don't help to get the Safari browser to display the video content as done by the Firefox browser for example.


So, the questions: 

Which one should be the preferential approach - in general to deliver mp4 files?

Does someone has the same issues with the Safari-Browser? What could help here?

In the mean time, any other suggestions would be greatly appreciated.

Thanks,
Leon