Process_broken_closest.php

<?php

/*    This file is part of DynamicEmulationATSCDASH.

    DynamicEmulationATSCDASH is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    DynamicEmulationATSCDASH is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with DynamicEmulationATSCDASH.  If not, see <http://www.gnu.org/licenses/>.
	*/
	
$micro_date = microtime();
$date_array = explode(" ",$micro_date);
$date = date("Y-m-d H:i:s",$date_array[1]);
#unlink ('../bin/timelog.txt');
#file_put_contents ( "timelog.txt" , "Start:" . $date . $date_array[0] . " \r\n" , FILE_APPEND );

ini_set('memory_limit','-1');//remove memory limit

#chdir('../bin/');
$currDir=dirname(__FILE__);

#Define Paths

$DASHContent="../../Work/Route_Sender/bin/ToS_1_0/";
$OriginalMPD= "MultiRate_Dynamic.mpd";

$Delay=0;	#How much would the AST of the patched MPD be lagging the current system time, i.e. how far in future is the AST (in seconds)?
$PatchedMPD="MultiRate_Dynamic_Patched.mpd";
#HTMLLocalStorage="/home/nomor/.config/google-chrome-unstable/Default/Local Storage/"

if (isset($_GET['astoffset'])) {
$offsetToNow=$_GET['astoffset'];
}
else
$offsetToNow = 0;

if (isset($_GET['type'])) {
	$requestType=$_GET['type'];
}

if($requestType=="mpd")
{
	processAndSendMPD($OriginalMPD,$PatchedMPD,$DASHContent,$offsetToNow);
}

function processAndSendMPD($OriginalMPD,$PatchedMPD,$DASHContent,$offsetToNow)
{
	$micro_date = microtime();
	$date_array = explode(" ",$micro_date);
	$date_array[0] = round($date_array[0],4);
	$date = date("Y-m-d H:i:s",$date_array[1]);
	//file_put_contents ( "timelog.txt" , "Tuned in:" . $date . $date_array[0] . " \r\n" , FILE_APPEND );

	$AST_SEC = new DateTime( 'now',  new DateTimeZone( 'UTC' ) );	/* initializer for availability start time */
	$AST_SEC->setTimestamp($date_array[1]);    //Better use a single time than now above
	//$AST_SEC->add(new DateInterval('PT1S'));
	$AST_SEC_W3C = $AST_SEC->format(DATE_W3C);

	preg_match('/\.\d*/',$date_array[0],$dateFracPart);
	$extension_pos = strrpos($AST_SEC_W3C, '+'); // find position of the last + in W3C date to slip frac seconds
	$AST_W3C = substr($AST_SEC_W3C, 0, $extension_pos) . $dateFracPart[0] . "Z" ;//substr($AST_SEC_W3C, $extension_pos);
	//file_put_contents ( "timelog.txt" , "Setting AST: " . $AST_W3C . " \r\n" , FILE_APPEND );

	$ASTO_SEC = new DateTime( 'now',  new DateTimeZone( 'UTC' ) );	/* initializer for availability start time */
	$ASTO_SEC->setTimestamp($date_array[1] - $offsetToNow);    //Better use a single time than now above
	$ASTO_SEC_W3C = $ASTO_SEC->format(DATE_W3C);

	$extension_pos = strrpos($ASTO_SEC_W3C, '+'); // find position of the last + in W3C date to slip frac seconds
	$ASTO_W3C = substr($ASTO_SEC_W3C, 0, $extension_pos) . $dateFracPart[0] . "Z" ;//substr($AST_SEC_W3C, $extension_pos);

		$MPD = simplexml_load_file($DASHContent . "/" . $OriginalMPD);
		if (!$MPD)
			die("Failed loading XML file");

		$dom_sxe = dom_import_simplexml($MPD);
		if (!$dom_sxe) 
		{
			echo 'Error while converting XML';
			exit;
		}
		
		$dom = new DOMDocument('1.0');
		$dom_sxe = $dom->importNode($dom_sxe, true);
		$dom_sxe = $dom->appendChild($dom_sxe);
		
		$periods = parseMPD($dom->documentElement);
		

		$cumulativeUpdatedDuration = 0;    //Cumulation of period duration on updated MPD
		$tuneInPeriodStart = 0;
		
		$MPDNode = &$periods[0]['node']->parentNode;
		
		$MPD_AST = $MPDNode->getAttribute("availabilityStartTime");
		$MPD_AST = $ASTO_W3C;//$MPDNode->getAttribute("availabilityStartTime");
		preg_match('/\.\d*/',$MPD_AST,$matches);
		$fracAST = "0" . $matches[0];
		$originalAST = new DateTime($MPD_AST);   
		$deltaTimeASTTuneIn = $AST_SEC->getTimestamp() + round($date_array[0],4) - ($originalAST->getTimestamp() + $fracAST);  //Time elapsed between the original AST and Tune-in time
		
		//file_put_contents ( "timelog.txt" , "TimeOffset: " . $deltaTimeASTTuneIn . ", Original ts:" . ($originalAST->getTimestamp() + $fracAST) . "Tune-in TS: " . ($AST_SEC->getTimestamp() + round($date_array[0],4)) . "\r\n" , FILE_APPEND );
		
		$MPDNode->setAttribute("availabilityStartTime",$AST_W3C);    //Set AST to tune-in time
		
		$periodStart;   //Start of this period in the iteration
		$duration;      //Duration of current period in the iteration
		$lastPeriodStart;   //Period start of the last period in the iteration
		$lastPeriodDuration;    //Period duration of the last period in iteration
		
		$responseToSend[1] = count($periods) - 1;
		
		for ($periodIndex = 0; $periodIndex < count($periods); $periodIndex++)  //Loop on all periods in orginal MPD
		{
			$periodStart = $periods[$periodIndex]['node']->getAttribute("start");
			$duration = somehowPleaseGetDurationInFractionalSecondsBecuasePHPHasABug($periods[$periodIndex]['node']->getAttribute("duration"));
			
			if($periodStart === '')
				$periodStart = $lastPeriodStart + $lastPeriodDuration;
			else
				$periodStart = somehowPleaseGetDurationInFractionalSecondsBecuasePHPHasABug($periodStart);	//Convert Duration string to number
			
			if($deltaTimeASTTuneIn < $periodStart)   //Tune-in is before this period, it stays intact (except that its start may need an update, which is optional for subsequent periods)
			{
				$periods[$periodIndex]['node']->setAttribute("start","PT". round($lastPeriodStart + $lastPeriodDuration,4)."S"); 
				//Set already for the next iteration
				$lastPeriodStart = $lastPeriodStart + $lastPeriodDuration;
				$responseToSend[] = $lastPeriodStart;
				$lastPeriodDuration = $duration;  
				continue;
			}
			
			//Set already for the next iteration
			$lastPeriodStart = $periodStart;
			$lastPeriodDuration = $duration;  
			
			if($deltaTimeASTTuneIn > $periodStart + $duration)   //This period is no more relevant and is not received, hence remove this
			{
				$dom->documentElement->removeChild ($periods[$periodIndex]['node']);
				$responseToSend[1] = $responseToSend[1] - 1;
				continue;
			}
			
			//The only case here is the period in which we tune in
			
			$videoSegmentTemplate = &$periods[$periodIndex]['adaptationSet'][0]['representation'][0]['segmentTemplate']['node'];
			$audioSegmentTemplate = &$periods[$periodIndex]['adaptationSet'][1]['representation'][0]['segmentTemplate']['node'];
			
			$videoTimescale = $videoSegmentTemplate->getAttribute("timescale");
			$videoSegmentDuration = $videoSegmentTemplate->getAttribute("duration");
			$videoStartNum = $videoSegmentTemplate->getAttribute("startNumber");
			$videoPTO = $videoSegmentTemplate->getAttribute("presentationTimeOffset");
			
			$newVideoStartNumber = ceil(($deltaTimeASTTuneIn - $periodStart)*$videoTimescale/$videoSegmentDuration) + $videoStartNum;
			//file_put_contents ( "timelog.txt" , "new video offset: " . ($deltaTimeASTTuneIn - $periodStart)*$videoTimescale/$videoSegmentDuration . "\r\n" , FILE_APPEND );
			$videoOffsetUpdate = ($newVideoStartNumber - $videoStartNum) * $videoSegmentDuration/$videoTimescale;
			
			$audioTimescale = $audioSegmentTemplate->getAttribute("timescale");
			$audioSegmentDuration = $audioSegmentTemplate->getAttribute("duration");
			$audioStartNum = $audioSegmentTemplate->getAttribute("startNumber");
			$audioPTO = $audioSegmentTemplate->getAttribute("presentationTimeOffset");
			
			$newAudioStartNumber = ceil(($deltaTimeASTTuneIn - $periodStart)*$audioTimescale/$audioSegmentDuration) + $audioStartNum;
			//file_put_contents ( "timelog.txt" , "new audio offset: " . ($deltaTimeASTTuneIn - $periodStart)*$audioTimescale/$audioSegmentDuration . "\r\n" , FILE_APPEND );
			$audioOffsetUpdate = ($newAudioStartNumber - $audioStartNum) * $audioSegmentDuration/$audioTimescale;
			
			// Find the smaller update offset of audio and video, set the other to the smaller
			$offsetUpdate = min($videoOffsetUpdate , $audioOffsetUpdate);
			
			$newAudioPTO = round($offsetUpdate*$audioTimescale + $audioPTO); //Round, since PTO is int type
			$newVideoPTO = round($offsetUpdate*$videoTimescale + $videoPTO); //Round, since PTO is int type
			
			//The adjusted period start and duration governed by new audio/video offset above.
			$periods[$periodIndex]['node']->setAttribute("start","PT". round($offsetUpdate + $periodStart - $deltaTimeASTTuneIn ,4)."S");         
			
			$remainingPeriodDuration = $duration - max($videoOffsetUpdate , $audioOffsetUpdate);
			
			$periods[$periodIndex]['node']->setAttribute("duration", "PT". round($remainingPeriodDuration,4) . "S");
			
			//Update again the last saved values for the next iteration
			$lastPeriodStart = $offsetUpdate + $periodStart - $deltaTimeASTTuneIn;
			$lastPeriodDuration = $remainingPeriodDuration;   
			
			$videoSegmentTemplate->setAttribute("presentationTimeOffset",$newVideoPTO);
			$videoSegmentTemplate->setAttribute("startNumber",$newVideoStartNumber);

			$audioSegmentTemplate->setAttribute("presentationTimeOffset",$newAudioPTO);
			$audioSegmentTemplate->setAttribute("startNumber",$newAudioStartNumber);
			
			//$periods[$periodIndex]['node']->removeChild ($periods[$periodIndex]['adaptationSet'][1]['node']);
		}
		
	//Set the updated MPD duration
	
	$MPDNode->setAttribute("mediaPresentationDuration","PT". round($lastPeriodStart + $lastPeriodDuration ,4) . "S");
	
	/*if($AdSource == 1 && count($periods) >= 2)
	{
		$BaseURL = $dom->createElement( "BaseURL", "../Ad2/");
		$TargetPeriod = $periods[count($periods) - 2];
		$TargetAS = $TargetPeriod['adaptationSet'][0]['node'];
		$TargetPeriodNode = $TargetPeriod['node'];
		$TargetPeriodNode->insertBefore($BaseURL,$TargetAS);
	}*/

	$BaseURL = $dom->createElement( "BaseURL", $DASHContent);
	$TargetPeriodNode = $periods[0]['node'];
	$MPDNode->insertBefore($BaseURL,$TargetPeriodNode);
		
	$dom->save($PatchedMPD);
	
	corsHeader();
	header("Content-Type: application/xml");
	$toecho = $dom->saveXML();

	echo $toecho;
	
	#file_put_contents ( "timelog.txt" , $latestFiles , FILE_APPEND );
	$micro_date = microtime();
	$date_array = explode(" ",$micro_date);
	$date = date("Y-m-d H:i:s",$date_array[1]);
	//file_put_contents ( "timelog.txt" , "Done:" . $date . $date_array[0] . " \r\n" , FILE_APPEND );
}
	exit;
/*Send out CORS header*/
function corsHeader()
{
	header("Access-Control-Allow-Headers: origin,range");
	header("Access-Control-Expose-Headers: Server,range");
	header("Access-Control-Allow-Methods: GET, HEAD, OPTIONS");
	header("Access-Control-Allow-Origin: *");
}

function &parseMPD($docElement)
{
    foreach ($docElement->childNodes as $node)
    {
        //echo $node->nodeName; // body
        if($node->nodeName === 'Location')
            $locationNode = $node;
        if($node->nodeName === 'BaseURL')
            $baseURLNode = $node;    
        if($node->nodeName === 'Period')
        {
            $periods[]['node'] = $node;

            $currentPeriod = &$periods[count($periods) - 1];
            foreach ($currentPeriod['node']->childNodes as $node)
            {
                if($node->nodeName === 'AdaptationSet')
                {
                    $currentPeriod['adaptationSet'][]['node'] = $node;
                    
                    $currentAdaptationSet = &$currentPeriod['adaptationSet'][count($currentPeriod['adaptationSet']) - 1];                    
                    foreach ($currentAdaptationSet['node']->childNodes as $node)
                    {
                        if($node->nodeName === 'Representation')
                        {
                            $currentAdaptationSet['representation'][]['node'] = $node;
                            
                            $currentRepresentation = &$currentAdaptationSet['representation'][count($currentAdaptationSet['representation']) - 1];

                            foreach ($currentRepresentation['node']->childNodes as $node)
                            {
                                if($node->nodeName === 'SegmentTemplate')
                                    $currentRepresentation['segmentTemplate']['node'] = $node;
                            }
                        }
                    }
                }
            }            
        }
    }
    
    return $periods;
}

function somehowPleaseGetDurationInFractionalSecondsBecuasePHPHasABug($durstr)
{
	    if(strpos($durstr,'.') !== FALSE)	//If indeed there is float values
		{
                        $temp = explode('.', $durstr);
			$durstrint = $temp[0] . 'S';
                        $temp1 = explode('.', $durstr);
                        $temp2 = explode('S',$temp1[1]);
			$fracSec = '0.' . $temp2[0];
		}
		else
		{
			$durstrint = $durstr;
			$fracSec = 0;
		}
		
        $di = new DateInterval($durstrint);

        $durationDT = new DateTime();
        $reft = clone $durationDT;
        $durationDT->add($di);
        $duration = $durationDT->getTimestamp() - $reft->getTimestamp() + $fracSec;
        
        return $duration;
}
?>