they play fine, on the computer, but not in this little app at all. no error messages at all, may want some verification. Yes' i'm using your tool because the file is problematic in it's dimensions, but the file 60fps, H264 high, 2560x1440 with AAC audio (but silent) plays fine in every player I have tried it with. suspecting it has unusual size or audio, how can i work out what's this app unhappy with about the file?...