The delay could be because the Android player (or any player) will first download files scheduled for playback from server’s library, so if the high res video file is huge, then depending on your network speed, you will experience delay up to the point, the client has completed download of the file.
In Android player, you can check the status screen to see the Download status.
However, if you are referring to gap between video’s then this thread might help:
rgds,
btech.