unfortunately i can't test the local play (I am not in Italy right now), but i will try to record a program and see it works afterwords.. What i see is through the TVHeadend status page is that the average signal strength is around 30% (which could be a bit poor).
But what i find interesting is that I get the same behavior when I play an HD channel, which uses around 8MBit, and a normal channel (around 4MBit)..
By the way, on my backend PI there's only the TVHeadend server running, so I guess no particular CPU/RAM usage is affected (here's the top output:
top - 22:04:01 up 1:31, 1 user, load average: 0.21, 0.13, 0.14
Tasks: 61 total, 1 running, 60 sleeping, 0 stopped, 0 zombie
%Cpu(s): 4.0 us, 4.0 sy, 0.0 ni, 90.6 id, 0.0 wa, 0.0 hi, 1.4 si, 0.0 st
KiB Mem: 447864 total, 431416 used, 16448 free, 25312 buffers
KiB Swap: 102396 total, 0 used, 102396 free, 352872 cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1951 hts 20 0 178m 16m 1648 S 12.8 3.9 2:59.15 tvheadend
5113 pi 20 0 4672 1456 1040 R 0.7 0.3 0:00.79 top
39 root 20 0 0 0 0 S 0.3 0.0 0:20.53 mmcqd/0
2164 pi 20 0 9392 1684 1052 S 0.3 0.4 0:01.71 sshd
1 root 20 0 2148 720 616 S 0.0 0.2 0:01.92 init
......
Is it possible that my ping is too high (50ms)?