LG BD390 issue

I have a couple of video files which seem to be very similar, in terms of container and codecs at least. But one plays and one doesn't. The one that doesn't is a 1080p video, and the TV I have this player hooked to is 720. Would that explain it? Basically, the player acts like it's starting to play the video for about a second or so, and then just returns to the menu without an error or anything.
I've done a little reading on LG and it appears their DLNA support is poor. Is this just a matter of setting up better transcoding? Heck, I'd be happy letting my PC transcode everything if it meant feeling reassured that the chances of having to deal with a file that won't play are low.
And in the case of this video in particular, do I need to get serviio to drop it down to 1080 to 720, and if so, how?
While I know xml and am somewhat familiar with codecs, containers, etc. I really don't have a good understanding of all this profile stuff.
I've done a little reading on LG and it appears their DLNA support is poor. Is this just a matter of setting up better transcoding? Heck, I'd be happy letting my PC transcode everything if it meant feeling reassured that the chances of having to deal with a file that won't play are low.
And in the case of this video in particular, do I need to get serviio to drop it down to 1080 to 720, and if so, how?
While I know xml and am somewhat familiar with codecs, containers, etc. I really don't have a good understanding of all this profile stuff.