title: Get youtube video url form webpage source
body: <p>Is it possible to get the download URL of currently playing video from source of YouTube webpage?Thanks in advance.Please help me.</p>
  
  <p>Actually I have a downloader but it is not working now.When I have tried with the URL provided by the downloader in browser it returns an error page says "Access to the webpage was denied".The Url that I got for a video is as 
      <strong>" <a href="http://r14---sn-h557snel.c.youtube.com/videoplayback?gcr=in&amp;ip=121.241.181.70&amp;upn=OOcjKEO_S6I&amp;cp=U0hUTFZQT19KU0NONF9OSlNGOmFRT2JSUUs2bDVi&amp;ipbits=8&amp;fexp=900148,920704,912806,928001,922403,922405,929901,913605,929104,913546,913556,908496,920201,913302,919009,911116,901451,902556&amp;ms=au&amp;mt=1357625350&amp;mv=m&amp;id=31a79fcdbfc6c2f6&amp;sparams=cp,gcr,id,ip,ipbits,itag,ratebypass,source,upn,expire&amp;expire=1357651559&amp;itag=18&amp;key=yt1&amp;newshard=yes&amp;source=youtube&amp;ratebypass=yes&amp;sver=3" rel="nofollow">http://r14---sn-h557snel.c.youtube.com/videoplayback?gcr=in&amp;ip=121.241.181.70&amp;upn=OOcjKEO_S6I&amp;cp=U0hUTFZQT19KU0NONF9OSlNGOmFRT2JSUUs2bDVi&amp;ipbits=8&amp;fexp=900148,920704,912806,928001,922403,922405,929901,913605,929104,913546,913556,908496,920201,913302,919009,911116,901451,902556&amp;ms=au&amp;mt=1357625350&amp;mv=m&amp;id=31a79fcdbfc6c2f6&amp;sparams=cp,gcr,id,ip,ipbits,itag,ratebypass,source,upn,expire&amp;expire=1357651559&amp;itag=18&amp;key=yt1&amp;newshard=yes&amp;source=youtube&amp;ratebypass=yes&amp;sver=3</a>"</strong></p>
  
  <p>Few months before the format of URL was 
      <strong>" <a href="http://o-o---preferred---sn-h557snes---v24---lscache3.c.youtube.com/videoplayback?upn=AmmxhSpq470&amp;sparams=cp,gcr,id,ip,ipbits,itag,ratebypass,source,upn,expire&amp;fexp=917013,906437,916626,922401,920704,912806,927201,925706,922403,913546,913556,916805,920201,901451&amp;ms=au&amp;expire=1353668177&amp;itag=18&amp;ipbits=8&amp;gcr=in&amp;sver=3&amp;ratebypass=yes&amp;mt=1353646087&amp;ip=121.241.181.70&amp;mv=m&amp;source=youtube&amp;key=yt1&amp;cp=U0hUSFZRVl9MUUNONF9OS1pCOmhtUTVMak5oTVNy&amp;id=c429fa5466ee9447&amp;newshard=yes" rel="nofollow">http://o-o---preferred---sn-h557snes---v24---lscache3.c.youtube.com/videoplayback?upn=AmmxhSpq470&amp;sparams=cp,gcr,id,ip,ipbits,itag,ratebypass,source,upn,expire&amp;fexp=917013,906437,916626,922401,920704,912806,927201,925706,922403,913546,913556,916805,920201,901451&amp;ms=au&amp;expire=1353668177&amp;itag=18&amp;ipbits=8&amp;gcr=in&amp;sver=3&amp;ratebypass=yes&amp;mt=1353646087&amp;ip=121.241.181.70&amp;mv=m&amp;source=youtube&amp;key=yt1&amp;cp=U0hUSFZRVl9MUUNONF9OS1pCOmhtUTVMak5oTVNy&amp;id=c429fa5466ee9447&amp;newshard=yes</a> "</strong></p>
  
  <p>So I don't know whether the downloader gives the correct URL. Please help me</p>