How to remove too much lag before downloading MP4 on the site?

Question

IIS

Hello, there is a site with online video and, accordingly, a server on Windows, when a user tries to turn on MP4 video on the site, it starts downloading after 10 to 50+ seconds (depending on the file size), while this delay does not even show the duration video. At the same time, FLV works perfectly: the download starts instantly or after a few seconds. I read somewhere that meta in MP4 is located at the end of the file, which is why you have to download it all first before playback starts.
Additional info: when you try to play a video from the server, you still get a delay of 1-2 seconds, which is a bit much considering the zero ping, FLV plays almost immediately.

Answer 1

We move meta tags to the beginning using Mp4box:
mp4box -inter 500 -add in.mp4 -new out.mp4
Plus, for browsers and players, if a certain buffer is full, the video will not play. In flash, the buffer size can be changed.

Answer 2

Tell me, please, what am I doing wrong?