.mkv file with multiple audio and subtitle streams ---> .mp4 file with one audio/sub

[ToxynSummers]

I'm new, so please excuse me if i've posted into the wrong area, but i have a pile of .mkv files which i've ripped from original DVDs which each have two different language audio streams and two different language subtitle streams, and im wanting to convert them to .mp4 files that will play on an ipod video with one audio stream and subtitles superimposed on top of the video (ie no use of vobsub in playback).

Does anyone know of an easy way to do this or a howto that can point me in the right direction?

Thanks.

[Adub]

Well first of all, you can use the MkvextractGUI to extract all of those streams, which you can then mux to mp4 with mp4box.
However, (as far as I know, atleast) you will have to re-encode the audio using the Textsub() or Vobsub() commands in Avisynth, if you want to superimose the subs onto the video.