I have had this problem for around two years(?) on some channels. I have tried to get it resolved on various occasions without success, including a change of TIVO box. I think I have isolated the problem in my case and have given up trying to get any action out of Virgin Media because I cannot get the message through to the overseas call-centres. I do have a workaround which might work for others too.
Background:
The TIVO box has three tuners which are numbered as 0,1, and 2 on the Diagnostics screen, so I will use those numbers in what follows.
When I reboot the box, it defaults to using tuner 1 for live TV. Diagnostics shows tuner 0 as "Not Tuned. General Tune Error", and tuner 1 with the live TV channel number being watched, e.g. 603 for Sky News, 607 for CNN. (Tuner 2 not relevant for now).
I can guarantee I will get occasional pixilation on those channels. There are others, but don't ask me to list them. If I go into Diagnostics, I will see the tuner 1 "RS Corrected" count sitting at 0 but regularly changing to a positive number and back to 0. By an amazing coincidence, these changes are around the same frequency I see pixilation on-screen.
My workaround is to get the TIVO box to use tuner 0 instead. To do this:
1. Flick live TV up one channel to whatever, pull up the programme information, and "press OK to record this program." This ties up tuner 1.
2. Change back to the channel I want to watch (e.g. 603) and check Diagnostics to see if it is allocated to Tuner 0 or Tuner 2. If on Tuner 0, I can exit Diagnostics, sit back and enjoy unpixellated TV.
3. If on Tuner 2, exit Diagnostics and flick down a channel to whatever, pull up the programme information, and "press OK to record this program." This ties up tuner 2.
4. Change back to the channel I want to watch. It will use Tuner 0 and all will be well.
5. At some point later, be sure to delete the unwanted recordings made by this dodge.
Just for the record, the SNR on tuner 0 is usually 41db, tuner 1 is usually 35db, and tuner 2, 36db.
This dodge is a pain in the backside to do but it works for me. As the same channel works fine on tuner 0 but not on tuner 1, and the problem has been repeated on two tivo boxes, it seems unlikely that the fault is with the equipment. The fact that tuner 1 exhibits RS Corrected errors and tuner 0 does not for the same channel suggests it must be a signal level problem, as does SNR of 35db (tuner 1) vs 41db (tuner 0).
I have tried explaining the above, step by step, to VM and it is hopeless. The last time I tried, I spent hours on the phone explaining this twice to two different people and asked for an engineer to check the levels. Request refused. The second person I spoke to said the information would be passed on for investigation and promised me that someone would call me back. This never happened.
Like I said at the start, I have had this problem for a very long time and do not expect it will ever get sorted out. I have given up banging my head against this particular wall. Hope this helps somebody! If you have the same problem and try the above, please post what you find.
