The audio is encoded as mono so this might not be supported by 8Player or this is triggering transcoding on the fly and the bitrate is too high for smooth playback. The aspect ratio issue would be caused by Mezzmo transcoding and not including the metadata 'displaymatrix: rotation of -90.00 degrees' from the file so that the iPhone does not know to rotate the video. Please try going to the properties of the file in Mezzmo and on the Transcoding tab click on Use Original file... to see if it plays the audio without transcoding and if it does then send an email to support [at] conceiva [dot] com and we will send you an updated device profile.