PHP - Youtube Mp4 Downloader

Yt2Mp4.php

<?php
function YT_IN_DX($url){
	$cookie_file_path = "cookies.txt";
	$agent = "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:43.0) Gecko/20100101 Firefox/46.0";
	$ch = curl_init();
	$headers[] = "Connection: Keep-Alive";
	curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
	curl_setopt($ch, CURLOPT_HEADER, 1);
	curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
	curl_setopt($ch, CURLOPT_USERAGENT, $agent);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
	curl_setopt($ch, CURLOPT_COOKIEFILE, $cookie_file_path); 
	curl_setopt($ch, CURLOPT_COOKIEJAR, $cookie_file_path); 
	curl_setopt($ch, CURLOPT_URL, $url);
	$res = curl_exec($ch);
	curl_close($ch);
	return $res;
}
function YT_V_INFO($v){
	$url="https://www.youtube.com/watch?v=$v";
	$html=YT_IN_DX($url);
	$video_links=Explode_Content('ytplayer.config = ', ';ytplayer.load', $html);
	$jsondownload1=json_decode($video_links, true);
	$json_str=$jsondownload1["args"]["player_response"];
	$jsn_str=str_replace("\u0026","&",$json_str);
	$streamin_data_json=json_decode($jsn_str, true);

	// Get and show full list of properties of this video
	//printf('<pre>%s</pre>', var_export($video_links, true));

	// Get and show video url and thumbnail
	printf('<h3>Requesting video data:</h3>%s</br>%s</br><img src="%s"/></br>', $jsondownload1["args"]["title"], $jsondownload1["args"]["loaderUrl"], $jsondownload1["args"]["thumbnail_url"]);
	
	printf('<h3>List of available formats:</h3><ul>');
	foreach ($streamin_data_json["streamingData"]["formats"] as $key => $value)
	{
		printf('<li>Mirror[%d]: <a href="%s" target="_blank">%s</a> - Quality: %s %s</li>', $key, $value["url"], $value["mimeType"], $value["quality"], $value["qualityLabel"]);
	}
	print('</ul>');

	// Get and show list of formats
	printf('<h3>Extra data:</h3><pre>%s</pre>', var_export($streamin_data_json["streamingData"]["formats"], true));
	
	// Returning index [0] direct url and quality
	#return sprintf('%s - %s', $streamin_data_json["streamingData"]["formats"][0]["url"], $streamin_data_json["streamingData"]["formats"][0]["quality"]);
}

function Explode_Content($first, $last, $string){
	$exp=explode($first,$string);
	// Check if ID is invalid
	if(count($exp) === 1)
		die('Invalid youtube video ID');
	$exp=explode($last,$exp[1]);
	return $exp[0];
}

// Include these functions at the top.
// Get direct url from Youtube with two lines

YT_V_INFO(isset($_GET["v"]) ? $_GET["v"] : 'xcJtL7QggTI');
?>