Comment 31 for bug 502642

@stefan: I guess for files on gvfs-mounted volumes only the filename extension is checked. My remote volumes are all mounted through NFS, which is handled by the kernel (not gvfs) and is fully transparent to the mime-type framework. So the header bytes are checked remotely too.

Unfortunately video/mp2t and application/x-linguist both match the extension *.ts, only have different header bytes. My patch for video/mp2t places its rule next to video/mpeg, which is AFTER application/x-linguist. That's why application/x-linguist has priority as long as header bytes do not count. (I did not want to break existing associations with my patch ;-)

To help fixing your issue, please try to modify your /usr/share/mime/packages/freedesktop.org.xml. Move the following section of text/vnd.trolltech.linguist (alias application/x-linguist) down to the end, just before the </mime-info>:
  <mime-type type="text/vnd.trolltech.linguist">
    ...
    <glob pattern="*.ts"/>
    <alias type="application/x-linguist"/>
  </mime-type>
Then rebuild your mime-database (don't care if there are "unknown media types"):
$ sudo update-mime-database /usr/share/mime

Are your files on the network share now "MPEG-2 transport stream"?