Sound and video are out of sync when I converted an MKV movie using Popcorn MKV AudioConverter

Follow the steps below to resync the audio and video.  Note that you need to have the Matroska tools in order to do this:

1.  Extract the DTS audio from the MKV movie using the mkvmerge GUI tool from the mkvtoolnix package.
2.  Convert the DTS to AC3 using an audio/video converter tool such as XMedia Recode, choosing Matroska Audio and selecting AC3 as the format
3.  Using the mkvmerge GUI tool, remux the AC3 audio with the original video