No audio on certain files

[gerontius]

(See also on "no sound" thread). I've encountered a similar problem, but specific, it seems, to m2ts (HD) files. For a while I was able to play these brilliantly on my Nexus 7 (not new model) from a USB 64GB Flash Drive using the Nexus 7 media importer & OTG cable. For some reason a couple of weeks back playback (video and sound) became jerky and slow. I've now uninstalled and re-installed both the media importer and BSPlayer Free. What I now have with m2ts files is smooth HD picture play but no sound! Other files (e.g. wmv) are no problem. Any advice would be welcome. Would PRO version resolve this?