Why do my Videos play at 1.5 speed on PS3



On my PS3 I can not get it to play videos at less then 1.5 speed?

Forgot to say they are MKV files is that why they play at only 1.5x normal?
I streamed to my cell and they play perfectly.

And is it possible to Stream from my home Computer to the PS3 at work over the internet. I work at a Mens Shelter and have lots of videos on computer at home.