1) We set the clock wfter the PCR packets is received.
However the time might be slightly different when the following PTS packet is analyzed.
To udjust the clock, knowing the bitrate of the file, we can calculate how many millseconds it
takes fir each single packets and update the PCR clock locally

Then the comparison with the PTS is more accurate

2) the threshold pcr pts is now in millseconds for better define the limit