How capture video thumbnail , when video is uploaded under media video type file? I'm using Core media module to upload video[Media Type is video,which has field video of 'file field type'].
This module will refer video.png as thumnail for all video uploaded from the local system.

I want to capture first frame of video as thumbnail when video is uploaded from the local system in media section.
I have seen 'PHP ffmpeg' , module , But i don't know the approach to follow to capture first frame of video.
 If i need to write a custom module to capture thumnail while saving media type of video, which hook function I need to use or please suggest me what apprach I can follow?
You can use https://www.drupal.org/project/media_thumbnails_video for this.
It has a dependency (php-ffmpeg/php-ffmpeg) that requires both the FFMpeg and FFProbe binaries to be installed on your server.