Converting pcm audio within an mpeg file to ac3

Does anyone know a way of extracting the pcm audio from an mpeg file so I can convert it to ac3 so that my wdlive box will play it?

Many thanks

TsRemux can extract the audio from an mpeg file, although the UI isn’t user-friendly for this task.

YAMB is another option (and a little more straightforward) for demuxing the audio track.

Do you already have a tool for the conversion process?

I have used mkvtovob initially so I could watch through the ps3 but then I bought a wdlive box and everything was fine until tthe latest firmware update of the wd live boxwhich now gives me white noise sound on my mpeg files with pcm sound.