Postby flx42 » 07 Apr 2014 10:41
Your display is 240x320 and according to the tech specs, your device can do video playback of WVGA (800x480) videos.
720p is 1280x720, 2.4x the number of pixels of WVGA.
I think your device cannot smoothly decode 720p, you will probably have dropped frames and/or a slower playback.