HI, can anyone tell me what these timers do and what are the best values to set them at for performance?

   <!-- <param name="timer-T1" value="500" /> -->

   <!-- <param name="timer-T1X64" value="32000" /> -->

<!-- <param name="timer-T2" value="4000" /> -->

<!-- <param name="timer-T4" value="4000" /> -->

<!-- <param name="auto-jitterbuffer-msec" value="60"/> -->