Sometimes I copy film from my PC to my smart phone and watch them on the way. I have 2 players: VLC and MX Player.
And with both I had problems. VLC works not very stable, sometimes lags, and when you select file based on it's location (but not from video section) VLC constantly forgets the place where you paused. And all these does not make me a happy user.
MX works better, but has one smaaaal issue: it does not play ac3 audio track. And definitely, 99.9% of my files do have audio exactly in ac3. I said 99.9%? I was wrong -100% for last several months.
You can install additional codecs for MX Player from Google Play. But first, you should find out what chipset your smartphone has (can you say this without googling?). Second, it did not work for me. And according to the comments not just for me.
Finally I found a solution: you should download all packaged together from the internet as zip file. After downloading, MX player self detects that package with codecs is downloaded, self finds proper codec for your smart phone inside zip, self restarts. Afterwards it start playing ac3 audio.
Link to the zip and some details I found here: http://www.phonearena.com/news/How-to-restore-full-audio-codec-support-AC3-DTS-in-MX-Player-Androids-best-video-playback-app_id64435
And now I’m a happy user of MX Player. Again!