Extends Unity VideoPlayer with methods to display the videos first frame, with with either a yielding coroutine or callback function when the video is ready to be displayed.

VideoPlayerExtentions.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Video;

public static class VideoPlayerExtentions 
{
    public static void ShowFirstFrame(this VideoPlayer player, System.Action onCompleteCallback)
    {        
        VideoPlayer.FrameReadyEventHandler frameReadyHandler = null;
        bool oldSendFrameReadyEvents = player.sendFrameReadyEvents;
        frameReadyHandler =  (source,index)=>{
            player.sendFrameReadyEvents = oldSendFrameReadyEvents;
            player.frameReady -= frameReadyHandler;
            onCompleteCallback();            
        };

        player.frameReady += frameReadyHandler;
        player.sendFrameReadyEvents = true;

        player.Prepare();
        player.StepForward();        
    }  

    public static IEnumerator ShowFirstFrame(this VideoPlayer player)
    {
        VideoPlayer.FrameReadyEventHandler frameReadyHandler = null;
        bool frameReady = false;
        bool oldSendFrameReadyEvents = player.sendFrameReadyEvents;
        
        frameReadyHandler =  (source,index)=>{
            frameReady = true;
            player.frameReady -= frameReadyHandler;
            player.sendFrameReadyEvents = oldSendFrameReadyEvents;
        };

        player.frameReady += frameReadyHandler;
        player.sendFrameReadyEvents = true;

        player.Prepare();
        player.StepForward();    

        while(!frameReady){
            yield return null;
        }    
    }  
}

Judging by your response, I have probably misinterpreted the use case of this script. If so, what is it for?

My Unity version is 2019.4.12f1

This script is for displaying the first frame of video until play is initiated by user interaction.

Ah okay I understand the logic now behind how it works.

I ended up coding something very similar to your suggestions with saving the initial frame, although I'm gonna experiment with AssetDatabase.ImportAsset(path) now, I hadn't seen that earlier.