I've been through a lot of my media that was getting transcoded to see what would play directly if forced and have made the following changes to the LGTV2013.prf profile if anybody wishes to use the same changes:

Code:
<avcontainer id="mpeg"...
  <audio>

    added:
      <format id="mp2">
      </format>

 
<avcontainer id="mpegts" ...
   <video>
      <format id="h264" 
         changed maxbitrate from 15000000 to 32000000

   <audio>
    added:
      <format id="mp2">
      </format>
      <format id="aac_latm"> <!-- Some UK DVB-T2 streams? -->
      </format>
Tried a h264 stream just under 32000000 which played fine but may be worth checking TV Device Settings -> Performance is set at 80Mbps if nothing passing through any interfaces less than 100Mbps or less if it is.

Also I've turned off Subtitles -> "Steam embedded subtitles" and "Burn subtitles into video files" as quite a few of my TS streams had embedded subtitles but we don't use them.

Very few of my video files now need transcoding.

Note: TV Model is 42LA620V-ZA and firmware 04.28.12. I'm pretty sure the TV used to be fussier than it is now with audio formats, maybe something improved in an update at some stage?