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BBC1 HD recording glitch

#1
Hello, I'm new here.
I get intermittent broken up glitchy picture when viewing recordings of BBC 1 HD.
This doesn't happen when watching live transmission ...EDIT it occasionally appears on live viewing, but seemingly only when recording a different channel
I've not seen it with other channels, SD and HD....EDIT: it HAS happened on other HD channels, but less frequently than 1HD
I first thought bad sector on hard disc, so installed custom FW and did disk check.
Also kept the bad recordings to avoid re-writing potential bad sector.
Tried a re-tune.
Still getting problems. Any ideas?

Ch54, signal strength 77%, quality 100%
Based in Bristol.

Many thanks
Ben
 
Last edited:

MymsMan

Ad detector
#2
Did the disk check reveal/correct any problems?
What are the current disk diagnostics values Webif->Diagnostics->Disk Diagnostics?

Strange that it only appears to affect one channel and occurred first before installing the Customised Firmware
Do you have any channels in the 800 range, are you picking up signals from more than one transmitter?
 

Luke

Well-Knwοn Мember
#3
Hello, I'm new here.
I get intermittent broken up glitchy picture when viewing recordings of BBC 1 HD.
...
Ch54, signal strength 77%, quality 100%
Based in Bristol.
BBC 1 HD would not be coming from Ch54. In the Bristol area Ch54 is used by only Mendip for the commercial non-HD PSB channels.

It would help if you could do a couple of look ups.
1/ On the web-if go to 'diagnostics, and from there 'mux info'. And then post a screen shot of the detail.

2/ Using the Humax remote control switch to watching BBC 1 HD and then
MENU > Settings > System > Signal Detection
and report back which channel number it displays.
 

Luke

Well-Knwοn Мember
#7
It rules out the usual suspect.
Are you sure that it only happens on recordings?

BBC1 HD and half the other channels are broadcast using the same format on the same frequency and so it is odd that you are saying that it only happens on BBBC 1 HD. Is it possible that you have only noticed it on BBC1 HD but that it could happen on BBC2 HD, ITV HD, Channel 4 HD and Channel 5 HD?

And a question to others on the forum: could there be any mileage in running fix-disk for this particular issue?
 
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Ben Howes

New Member
#8
Thanks for reply Luke
I've not been able to reproduce the error on the other HD channels. It is slightly intermittent in that most BBC1HD recordings are glitching but not all. There was glitching on one occasion when I used pause on BBC1HD - presumably this is identical to record.
I will try another retune.
I did run fix-disk after I installed the custom firmware. I didn't detect any issues.
If there's nothing that's easy to mend, I can survive with only recording BBC1 SD as the bit rate is good anyway.
Best wishes all
 

Trev

The Dumb One
#10
I can survive with only recording BBC1 SD as the bit rate is good anyway.
But the definition isn't as good regardless of the bit rate. Depends how big a TV you replay on and how far you sit from it. I'd sooner record in HD with minor glitches. But it must be most annoying.
 
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Ben Howes

New Member
#12
Problem has recurred. Inevitably. This time I reproduced it when watching live HD channels (BBC1HD and BBC2 HD) and recording an SD channel. This time it was not isolated to BBC1HD.
I could simultaneously record and watch two HD channels.
Any offers? Hard disc?
 

MartinLiddle

Super Moderator
Staff member
#13
Problem has recurred. Inevitably. This time I reproduced it when watching live HD channels (BBC1HD and BBC2 HD) and recording an SD channel. This time it was not isolated to BBC1HD.
I could simultaneously record and watch two HD channels.
Any offers? Hard disc?
The hard drive SMART data looks OK to me. Can you watch HD without using the Humax and if so does that suffer from breakup? Have you considered the possibility of local interference?
 
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Ben Howes

New Member
#14
I've never seen glitching on live viewing of HD channels - only on recordings; or live viewing in tandem with an different channel on record.
I'll plug the aerial into the TV and check it's okay. Thanks for the suggestion.
 

Black Hole

May contain traces of nut
#15
So far you have only shown us static signal strength/quality - the figures in the WebIF diagnostics are only those that were stored at the time of the retune. You need to use Menu >> Settings >> System >> Signal Detection, select the HiDef channel number and monitor the signal/quality bars over a few minutes. If quality is rock solid at 100% you can rule that out as your problem.
 
#16
Signal strength and quality can vary over time and different tuners can be better at handling it than others. Glitches are more likely to be due to signal problems than disk problems especially if the disk diagnostics don't show problems.

Some days I can watch HD programmes without problem while other days it is totally unwatchable so I only record in SD but even then I sometimes get glitches that cause the losses of a few seconds of recordings. Before I got my Humax I had a Sagem model which was so glitchy that I took it back to John Lewis and changed it for the Humax - a decision that I have never regretted.

I wonder if there is something about the recording process that causes minor signal faults that are barely noticeable when watching live to become more visible on replay.
 
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Ben Howes

New Member
#18
I studied the signal strength detection until it timed out back to the programme. It never dropped below 75%.
Last night I recorded, and simultaneously viewed live Taboo on BBC1 HD. There was no no noticeable glitch during viewing. However the recorded file will not even play - "recording failed, lack of signal". There were no other recordings going on and I didn't chase-play.
Could it be there is something wrong with one of the tuners but not the other?
 
#20
I studied the signal strength detection until it timed out back to the programme. It never dropped below 75%.
Last night I recorded, and simultaneously viewed live Taboo on BBC1 HD. There was no no noticeable glitch during viewing. However the recorded file will not even play - "recording failed, lack of signal". There were no other recordings going on and I didn't chase-play.
Could it be there is something wrong with one of the tuners but not the other?
.
You should be looking at the signal quality which detects the built in capability of digital to correct transmission errors. A quality of 100% signifies no error correction is required.