Process Video using FFMPEG in Laravel

video.php

    public function addVideo(Request $request) {
        $video = $request->file('video');
        $user = $request->user();


        $mainFileName = Str::random(6) . now()->timestamp . "." . $video->getClientOriginalExtension();
        $previewFileName = Str::random(6) . now()->timestamp . ".mp4";

        $mainFilePath = 'uploads/' . $user->uid  .'/video/'. $mainFileName;
        $previewFilePath = 'uploads/' . $user->uid  .'/video/'. $previewFileName;
        $overlayedFilePath = "uploads/" . $user->uid . "/video/overlayed_" . $video->id . ".mp4";
        $watermarkFilePath = 'watermark.png';


        $picName = 'uploads/' . $user->uid  .'/video/preview.jpg';

        //save locally
        Storage::disk('public')->put($mainFilePath, file_get_contents($video));

        // this would convert the video to a 480p mp4 video
        exec("ffmpeg -i '$mainFilePath' -s hd480 '$previewFilePath' ");
        
        //  this would give you a screenshot at the 5th second. Change the number after
        // -ss to choose the second of the video you want the pic to be taken at
        exec("ffmpeg -y -i '$mainFilePath' -ss  5 -vframes 1 $picName");


        while(!file_exists($previewFilePath)){
            sleep(1);
        }
        
        // this would add a watermark on the video to the bottom left
        exec("ffmpeg -i 'temp/$previewFilePath' -i '$watermarkFilePath' \-filter_complex \"[0:v][1:v] overlay=W-w:H-h:enable='between(t,0,20)'\" \-pix_fmt yuv420p -c:a copy '$overlayedFilePath'");


        // do any further processing

        return response( array( "message" => "Video Uploaded.", "data" => [
            "video_file" => $mainFilePath,
            "video_preview_file" = $previewFilePath,
            "video_pic_file" => $picName
        ]  ), 200 );

    }