使用PHP解析MRSS - 子元素

I know child elements have been discussed a lot, but I've gone through the helpful answers to related questions and can't seem to get it working (new to coding, so bear with me).

Here's what I'm working with:

rss xmlns:media="http://search.yahoo.com/mrss/" xmlns:bc="http://www.brightcove.tv/link"       xmlns:dcterms="http://purl.org/dc/terms/" version="2.0">
<channel>
<title>Search Videos By Criteria</title>
<link>...</link>
<description/> 
<copyright>Copyright 2014</copyright>
<lastBuildDate>Thu, 25 Sep 2014 13:29:49 -0700</lastBuildDate>
<generator>http://www.brightcove.com/?v=1.0</generator>
<item>
<title>5 best guards in Lakers history</title>
<link/>
<description>...</description>
<guid>video3805826070001</guid>
<pubDate>Thu, 25 Sep 2014 05:11:39 -0700</pubDate>
<media:content duration="121" medium="video" type="video/mp4"  url="http://videos.usatoday.net/Brightcove2/29906170001/2014/09/29906170001_3805837947001_5-BEST-GUARDS-IN-LAKERS--HISTORY-final.mp4?videoId=3805826070001"/>
<media:group>...</media:group>
<media:keywords>jerry west,derek fisher,Gail Goodrich,losangeleslakers,SMGV,USA Today Sports,Kobe Bryant,video big board,sports,basketball,lakers,magic johnson,nba
</media:keywords>
<media:thumbnail height="90" url="http://videos.usatoday.net/Brightcove2/29906170001/2014/09/29906170001_3805822421001_Screen-Shot-2014-09-25-at-8-06-28-AM.jpg?pubId=29906170001" width="120"/>
<media:thumbnail height="360" url="http://videos.usatoday.net/Brightcove2/29906170001/2014/09/29906170001_3805709286001_Screen-Shot-2014-09-25-at-8-06-28-AM.jpg?pubId=29906170001" width="480"/>
<bc:titleid>3805826070001</bc:titleid>
<bc:duration>121</bc:duration>
<dcterms:valid/>
<bc:accountid>44854217001</bc:accountid>
</item>

I'm using the following SimpleXML_Parser script to pull most of the info out that I need:

<?php
$html = "";
$url = "http://api.brightcove.com/services/library?command=search_videos&any=tag:NBA&output=mrss&media_delivery=http&sort_by=CREATION_DATE:DESC&token=NU-nMdtzfF8z9NNinlAgM4c9S-9BBfKpm6gFISdwyk-AnQ84efFBbQ..";
$xml = simplexml_load_file($url);
for($i = 0; $i < 80; $i++){
$title = $xml->channel->item[$i]->video;
$link = $xml->channel->item[$i]->link;
$title = $xml->channel->item[$i]->title;
$pubDate = $xml->channel->item[$i]->pubDate;
$description = $xml->channel->item[$i]->description;/* The code below starting with $html is where you setup how the parsed data will look on the webpage */
$html .= "<div><h3>$title</h3><br/>$description<p><br/>$pubDate<p><br/>$link<p><br/>$titleid<p><br/></div><iframe width='580' height='360' src='http://link.brightcove.com/services/player/bcpid3742068445001?bckey=/*deleted API key&bctid=$titleid' frameborder='0'></iframe><hr/>";}
echo $html;/* tutorial for this script is here https://www.youtube.com/watch?v=4ZLZkdiKGE0 */?>

What I need to be able to parse out of the feed is the string of number assigned to "titleid"

I have tried adding in variations on approaches for pulling out child elements, such as:

$titleid = $xml->children(‘media’, true)->div->children(‘bc’, true)->div[$i]->titled;

But not having any luck. I'm sure it's something obvious to a seasoned developer, but again, I'm a newbie.

Any suggestions?

Thanks for any help!

To parse MRSS properly you need first to put the getNamespaces to true.

Then select the namespace $xml->channel->item[$i]->children($namespaces['bc']) finaly you can extract the wanted value from it in your case id

<?php

$html = "";
$url = "http://api.brightcove.com/services/library?command=search_videos&any=tag:NBA&output=mrss&media_delivery=http&sort_by=CREATION_DATE:DESC&token=NU-nMdtzfF8z9NNinlAgM4c9S-9BBfKpm6gFISdwyk-AnQ84efFBbQ..";
$xml = simplexml_load_file($url);
$namespaces = $xml->getNamespaces(true); // get namespaces

for($i = 0; $i < 80; $i++){
  $title = $xml->channel->item[$i]->video;
  $link = $xml->channel->item[$i]->link;
  $title = $xml->channel->item[$i]->title;
  $pubDate = $xml->channel->item[$i]->pubDate;
  $description = $xml->channel->item[$i]->description;

  $titleid = $xml->channel->item[$i]->children($namespaces['bc'])->titleid;

  echo $title_group .'<br>';

}