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Persistent Pixelation on Playback

Last.To.Know

Last.To.Know

Member
I'm getting Pixelation whilst playing recordings and live TV.

Is this a hard disk issue?

Could it be something else?

Could fix-disk fix this?

Any help gratefully received.
 
prpr said:
No.
Yes.
No.
Fix your aerial etc.
Click to expand...
A few years ago I would have also answered no for the first suggestion. There is a discussion somewhere on hummy.tv where it appeared the overhead of a disk on its way out appeared to be the cause of the experienced pixelation.
But in this case that obviously is not the situation as the original question would have at least refereed to the SMART data for the HDD if it indicated an HDD in poor health.
 
That's not entirely true. Excessive system load due to HDD retries (thrashing) is known to affect live reception (the system is late servicing the receiver subsystem). However, a situation like that would result in gross failures in recordings, not just pixellation.

If the playback of recordings is repeatably flawed, we must conclude the errors were recorded as such so by far the most likely is reception issues. The weather conditions have not been favourable lately, but that's changing.

Comparison with the TV will tell you nothing. Far better to monitor the signal quality figures at Menu >> Settings >> System >> Signal Detection.
 
Last edited:
Well, the signal quality figures at Menu >> Settings >> System >> Signal Detection are terrible.

Channel 21 is best at 100% quality and 52% strength.

As this is the mux for HD channels, I am happy with that.

All the other channels waver between 10% and 30% quality resulting in unwatchable TV channels.

I should say that the pixelation was on HD channels, live and recordings.
 
Last.To.Know said:
I should say that the pixelation was on HD channels, live and recordings.
Click to expand...
"Was" being the operative word. You don't know what the Q figure was at the time.

Black Hole said:
If the playback of recordings is repeatably flawed, we must conclude the errors were recorded as such so by far the most likely is reception issues. The weather conditions have not been favourable lately, but that's changing.
Click to expand...
Additional: in my experience, recordings made when the live picture shows pixellation don't just pixellate on replay, they have hiccups.
 
Last.To.Know said:
the signal quality figures at Menu >> Settings >> System >> Signal Detection are terrible.
Channel 21 is best at 100% quality and 52% strength.

All the other channels waver between 10% and 30%
Click to expand...
52% strength isn't terrible, it is more than adequate. The others are terrible for quality but you didn't report strength. Make a table of channel, strength, quality.
Last.To.Know said:
As this is the mux for HD channels, I am happy with that.

I should say that the pixelation was on HD channels, live and recordings.
Click to expand...
Obviously it's OK now but it wasn't then. That doesn't mean it's going to be OK in the future.
Like I said in post #2, "fix your aerial etc." or at least start investigating all links in the chain, whatever they may be.
I will virtually guarantee you that it's not going to get better by doing nothing.
 
prpr said:
52% strength isn't terrible, it is more than adequate. The others are terrible for quality but you didn't report strength. Make a table of channel, strength, quality.

Obviously it's OK now but it wasn't then. That doesn't mean it's going to be OK in the future.
Like I said in post #2, "fix your aerial etc." or at least start investigating all links in the chain, whatever they may be.
I will virtually guarantee you that it's not going to get better by doing nothing.
Click to expand...

This is from the Web-IF Mux Info page.

ChannelFrequencySignal StrengthSignal QualityNetworkMuxTypeChannels>799
21474.0 MHz
51%
100%
Cambs & BedsPSB3/BBC BDVB-T2 (HD;6)11 view 0
24498.0 MHz
60%
30%
Cambs & BedsPSB2/D3&4DVB-T (SD;2)12 view 0
27522.0 MHz
60%
30%
Cambs & BedsPSB1/BBC ADVB-T (SD;2)24 view 0
33570.0 MHz
54%
20%
Cambs & BedsCOM4/SDNDVB-T (SD;2)10 view 0
36594.0 MHz
57%
20%
Cambs & BedsCOM5/ARQ ADVB-T (SD;2)11 view 0
48690.0 MHz
25%
30%
Cambs & BedsCOM6/ARQ BDVB-T (SD;2)16 view 0

It reflects the live values from the TV interface.

BH, yes, I'd say the playback hiccups.

I will say I am puzzled as to why it appears that my signal from Sandy Heath seems to be weaker.
 
As alluded to in the thread already we have had steady High Pressure about recently that might affect your reception https://www.bbc.co.uk/reception/work-warning/weather-warning/waw-high-pressure That is now changing, so stuff might improve (or not).

Location (approx) or your Freeview interference prediction numbers might confirm if that was more or less likely to be a cause... https://www.freeview.co.uk/corporate/detailed-transmitter-information


FWIW my Sandy Heath numbers here (not far from Bedford) are S:30-40% but Q@100% for all 6 multiplexes from a loft aerial and 2-way passive splitter. My Panny OLED TV reports 100/100 for all except ch48 which is variable around 30%S and 98% Q (steady) {BER varying around 2E-04 or better}. If we used DTT more I'd have to fix that with a low gain aerial amplifier (as the RF out on the HDR-Fox-T2 is broken).
Without the splitter (last retune numbers still in WebIF) S was 70-73%.
 
Last.To.Know said:
This is from the Web-IF Mux Info page.
Click to expand...
But when did you re-tune, which is when those figures were stored?
It reflects the live values from the TV interface.
Click to expand...
OK, so if the above was a while ago, then nothing much has changed. If it was today then it doesn't tell us anything else.
COM6 really is terrible. I'm surprised it worked at all.
I will say I am puzzled as to why it appears that my signal from Sandy Heath seems to be weaker.
Click to expand...
Weaker than what?

Can you provide any details of your aerial signal chain? At the risk of repeating myself yet again...
 
Thank you, Rodders.

The FreeView checker doesn't report any problems for my location.

prpr, The table is the same as if I'd jotted the values down from the telly.

Last retune was about a month ago.

Weaker than previously when I didn't have this problem.

You are probably right that the problem may lie in the aerial signal chain.

It's not something I'm prepared to tackle today.

I thank you for your helpful posts.
 
Rodders53 said:
As alluded to in the thread already we have had steady High Pressure about recently that might affect your reception
Click to expand...
It was a lot higher last week (1035 hPa) compared to now (1022). I doubt that is the root cause.
except ch48 which is variable around 30%S and 98% Q (steady)
Click to expand...
I have trouble with Ch48 from Mendip (and 47 from Wenvoe) and, elsewhere, 48 from Waltham is noticeably worse than the rest. I wonder why.
I'd have to fix that with a low gain aerial amplifier (as the RF out on the HDR-Fox-T2 is broken).
Click to expand...
Toolstation seem to have stopped carrying the Proception PROMHD12M which is a shame. The 14 is still available (for more money of course).
 
OK. so I have re-jigged my aerial signal chain.

Aerial > Restoretv.uk filter > signal amplifier > Humax

This has boosted the signal strength of all the channels as reported by the Menu >> Settings >> System >> Signal Detection

Sadly, the quality values remain the same.

[Edit] I spoke too soon!

All channels now reporting 100% quality!

Humax obviously needed to think about it for a few minutes.

All previously unwatchable TV channels clear as day.

Thank you, prpr, for pushing me in this dirction.

FYI I removed an old filter that was fitted to combat changes in the mobile network and replaced it with the restoretv.uk filter.

Thank you all for your helpful replies.
 
Last edited:
Last.To.Know said:
Aerial > Restoretv.uk filter > signal amplifier > Humax
Click to expand...
That looks good.
This has boosted the signal strength of all the channels as reported by the Menu >> Settings >> System >> Signal Detection
All channels now reporting 100% quality!

Thank you, prpr, for pushing me in this direction.
Click to expand...
That's good too. No probs.
FYI I removed an old filter that was fitted to combat changes in the mobile network and replaced it with the restoretv.uk filter.
Click to expand...
I'd be interested in seeing (decent) pictures of both filters if you have an opportunity to take some. I bought my own filter. I hadn't heard of restoretv - maybe they took over what was at800 (or whatever they were called during the 800 MHz clearance programme).
Black Hole said:
There needs to be a health warning in large letters added to that WebIF page.
Click to expand...
That was added ages ago (OK, not in large (friendly) letters, but it's there in red).
 
Thanks, interesting.
So your old filter doesn't get rid of frequencies between 700 and 800MHz, and the new one does.
Conclusion: you were suffering from mobile services interference which is upsetting your amplifier. This is why you need the filter before the amp., as you correctly have it!
I'm glad I bought my own filter with proper F connectors though, but I don't know if there's much 700-800 stuff here yet - certainly no 5G service on my dog'n...

BTW, your table cribbed from the WebIf doesn't work properly as it includes links to your local network IP 10.0.0.14:
Code: 
[td]21[/td]
[td]474.0 MHz[/td]
[td][IMG alt="51%"]http://10.0.0.14/img/percentimage.png[/IMG][/td]
[td][IMG alt="100%"]http://10.0.0.14/img/percentimage.png[/IMG][/td]
[td]Cambs & Beds[/td][td]PSB3/BBC B[/td]
[td]DVB-T2 (HD;6)[/td]
[td]11 [URL='http://10.0.0.14/diag/mux.jim#'][IMG]http://10.0.0.14/images/421_1_00_CH_Title_2R_Arrow.png[/IMG]    view[/URL][/td]
[td]0[/td]
 
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