Playpath or Saving as for file name ?

[megalivestream]

I use rtmpdumphelper . i used it against a live stream tv channel and got this output

tcUrl: rtmp://stream4.dmi.ae/live4/_definst_
pageUrl: http://www.dmi.ae/live.asp?lang=ar&ChannelID=1
Playpath: mp4:dubaitv_source
Saving as: mp4_dubaitv_source

What would be the file name in this case ?
mp4:dubaitv_source OR mp4_dubaitv_source

and it appears this has an mp4 in the name , does this mean the file ends with .mp4 and not flv ?
please clarify .

Thanks