are you on power kernel?please give us more information..we'd appreciate it..and it'll be easier for us to help u out =) if u are on power kernel, which profile are you using?XLV?ULV?LV?..try changing to default profile [kernel-config load default] when using certain profiles, the phone cannot handle the load, hence reboot will occur.. this happens as well on youtube videos, some games (particularly preenV)..so, changing your profile to default or higher Hz should solve it.. does it occurs with every video?or just one particular video? what was the last app u installed?