php

<?php
        $joinVideosTXT="joinVideos.txt";
		$joinVideos=fopen($joinVideosTXT,"w+");





		//Writes "joinVideos.txt"
		$video="nameVideo1";
		$video2="nameVideo2";
		$pathVideo=$video.".webm";
		$pathVideo2=$video2.".webm";
		$strVideo="file '".$pathVideo."'"."\r\n";
		$strVideo2="file '".$pathVideo2."'"."\r\n";

		fwrite($joinVideos, $strVideo);
		fwrite($joinVideos, $strVideo2);
		fclose($joinVideos);



		$ffmpeg="ffmpeg.exe";
		$videoFinal="videoFinal.webm";

		// unlink($videoFinal);//remove previous $videoFinal
		$cmd="$ffmpeg -f concat -i " .$joinVideosTXT." -c copy ".$videoFinal;


		system($cmd);

	?>


	<video controls="controls">
		<source src="videoFinal.webm" type="video/webm">
	</video>
</body>