Hello guys hope everything it's allright



so here is the problem, i'm trying to render a video file using vegas 10 to have 5.1 surround sound from a stereo track, every time i try to render i get this message:

" an error ocurred while creating the media file xxx.mp4 "

" an error ocurred while opening a codec "


does vegas needs an external 5.1 sound codec in order for this to work, or im just trying to render this the wrong way...

by the way im using this template


internet 16:9HD 25p


sony avc (mp4, m2ts,avc)

the resulting file would be an mp4 video file



than very much in advance for your ideas