IMPORTANT:
The stream relay needs a fast CPU. Not every STB is fast enough.
If you cannot fix stuttering with the following guide, likely your CPU is too slow.
For best performance, the "Include ECM in http streams" setting must be enabled.
If your image supports it (openpli, openatv), you can find it here:
OpenWebif -> Settings -> Customize New change: openwebif -> settings -> extras
If the setting is not available, you may need to adjust the "ECM fix delay"
setting in oscam webif (Config -> Stream Relay).
Increase/Lower it until there is no stuttering.
When using VU+ devices, make sure to use the latest drivers (June 2015), if you encounter any problems.