The VideoLAN Forums

VLC converted win7 WMC .wtv file to MP4, plays video but no sound. VLC plays the .wtc OK with sound. Want to reduce the wtv size.
I could send the files' properties to you if I knew how to extract to text, but there doesn't seem to be a way.

Recording and transcoding are somehow broken in recent builds, this is a known issue awaiting for a fix.
Meanwhile you should use an older version (v2.0.8 or 2.1.5) or a v3.0.0 nightly build.