Does your RPi freeze?

[jona9]

It could be a limitation of the WiFi adapter you use. I had the same problem initially, with a 256Mb Pi. All videos would freeze up every few seconds.

Fortunately my router showed that the Pi was connected at 5Mb/second, while all the other WiFi devices in my network connected at 50 Mb/s. After replacing the no-name adapted with an Edimax 7811, the Pi connected at 50Mb/s and there was no lag -my files are 5Mbit/second at most.

You could have issues if the WiFi access point signal is too weak. Or if the access point does not support 801.11n