I am implementing a screen capture widget to create a video. The video was successfully created in MP4 format and I can view it in my app and then I posted it to my web. However, on the web, I cannot see the video preview, only when I download the video and view it on my phone can I see it. I think the problem is that there is some missing format that makes the video not playable on Https. Here is my code:

I am working on an app where i first extract audio from a video, then transcribe it and then i wanna attach that transcribed captions or subtitles to the original video.