YouTube MP4 (!) to anything: No sound

[Schlumpf]

I downloaded an MP4 video from YouTube using the "Get YouTube"-Bookmarklet. So I got an MP4 not an FLV.
I made some subtitles for a Keynote presentation and want to burn them in (Quicktime doesn't like subs with MP4).
VLC tells me the video codec is: "avc1", and the audio codec: "mp4a". No preset in ffmegX will give me sound in the resulting file.

Is this a known problem? Any ideas? Maybe some workarounds with other software?

TIA

[Baldrick]

avidemux can burn in subs in mp4 h264. under filters add the subtitle filter.

Or maybe try subler to make a mp4 with switchable subs.