My LG TV played .mkv files from USB, but not via DLNA. After selecting .mkv file, “This file is invalid” dialog showed and TV restarted.
I have used various DLNA servers on Windows, Linux and today I tried Serviio. I just deleted “transcoding” tag int “profiles.xml” for “LG TV” profile and videos are played smoothly (without transcoding on my AMD64 3200+, 2GB@333Mhz).
Another nice thing Serviio does is automatically identifying series, grouping them and showing half-watched videos.