slomo effect is lost

[wholeinsoul]

Hi. The video created by this application does play in slomo on iphone and mac quicktime player. But other players like google drive[whatever default player they have], videojs player, AVPlayer [in iphone app] do not play it in slow motion. But if I record slomo video using the native iphone camera app, all the above listed videos are able to play it in slowmo. Looks like there is some information that needs to embed inside the video file. Any clues ?

Thanks.