I have noticed smilar trouble:
When VDR playbacks a recording, and I pause playback and put play again, video starts playing, then stops for less than second after about 5 seconds, then plays, after two seconds stops again for one second, and then plays smoothly.
I have noticed "replay stuttering" trouble sometimes, but increasing PLAYERBUFSIZE to MEGABYTE(8) resolved the trouble.
Boguslaw Juza