I use MJPEG codec 720x576 (keyframe-every frame).
on Win7x64 @MSI GT60 notebook for gamers with Corei7-3610QM & NV670MGTX3Gb+Intel4000.
Nice working for simple play is
LAV filters x64
You can Google them.
For codecs management (merit change & register/unregister) i use
(my favorite - GSPOT works only with x32 codecs)
We must remember : x64 soft use only x64 video/audio codecs !
MAX, unlike graphedt 64, strangely does not respond to changes in merits and does not react to ban the use of certain codecs :(