Help from VM techie needed. Freezing/corrupt pics

SteveDimond · 22-07-2008, 12:47

Hi,

I am hoping that a Virgin Media techie type can help me with my problem.

I live in Wokingham, Berks (RG40 postcode). Since 7th July (at least) I have had a problem with freezing/corrupt pictures with my digital TV service. The problem gets worse (i.e. more frequent) as the day progresses and seems to be worse on the BBC and ITV channels. There are certain times in the evening when you can guarantee that the problem will occur - for example, within five minutes either side of 8:20pm, 9:30pm and 9:50pm - but by midnight the problem is occurring more or less regularly. The frequency of the problem does not depend on how long the box has been turned on for, and the box is not overheating.

So far I have had two engineers out and neither have fixed the problem. The first changed the attenuator, the second changed the attenuator and the box itself. However, as the problem occurs only very infrequently during the day, it is impossible for the engineer or me to be sure that the problem has been cured at the time, and it is only when I am watching TV in the evening that I can tell that the problem has not gone away. I have a third engineer coming out on Friday, but I feel that I need to be prepared with something useful to say to him to get to the root of the problem.

The picture corruption I am getting is particularly interesting. To my eyes, it looks like an encoding problem rather than a box/cabling problem. Generally speaking, the top or bottom half of the screen will go blocky and freeze, while the other half will carry on as normal. I recorded some of the freezing last night on my DVDR and, stepping through the freezes one frame at a time, I noticed something really peculiar. During New Tricks, scene A was followed by scene B. The picture froze twice during scene A with a sort of horizontal tearing or shearing effect. Then, scene B started and for two frames the picture was perfect. After two frames, however, the top third of the screen continued moving as normal, while the bottom two-thirds first went very blocky, and then froze with an image from the previous scene! This continued for about one-third of a second, before the bottom half went blocky again and then the image corrected itself. With the naked eye it was not possible to make out what had happened at the time.

I think the problem is at the head-end. I cannot see how either the box or the cabling could "remember" a previously transmitted image and decide to partially display it later. However, I'm surprised that no-one else has reported the problem.

Any advice would be appreciated.

Regards,
Steve

Nedkelly · 22-07-2008, 19:15

What type of box is it ? in the tech stuff pages when it does this are there post errs logs on the screen .If there is write them down ie post err 459 x6 this means on freq 459 there has been 6 errs .If the level to the box is ok then it could be a network problem are there any one else you know in your street with the same problem ?

SteveDimond · 22-07-2008, 22:26

Hi,

The box is a brand new Samsung. It was installed by the second technician on Friday and replaced a Samsung that I had had for a few months.

There are no post-RS errors, and the SNR is 48.8dB. Both VM technicians have thought the signal a little high and have increased the attenuation. The second techie thought that the levels were now OK.

I don't believe that there is anyone else in my streeet that still takes VM TV. Most are on Sky or have erected monster aerials to get Freeview. When the green box in the road was vandalised a couple of years ago and all the cables torn out I was the only person whose TV service was affected.

About three months ago there was a problem with one of the main green boxes in the town which gave rise to freezing pictures. This took five days to get fixed as I was the only person to complain for several days, even though the picture was truly appalling all the time. At that time I was getting several hundred Post-RS errors per second, and several thousand Pre-RS errors! My current problem seems different: I still think the problem is either in the encoding at the head-end, or in the feed VM is taking.

Would it be worthwhile for me to show the techie my recording and step through it as described, or will he be uninterested? Unless others have complained is it likely to remain unfixed?

Steve

Nedkelly · 22-07-2008, 22:33

It could be a couple of things .Some of the new samsungs have a new type of tuner in them this might be a problem .Or it could a problem in the street cab as if it was the headend it would be picked up as it would affect a larger area .If possible ask the tech if the pricipal tech could have have look as these techs have more time to spend at a job

SteveDimond · 23-07-2008, 11:28

Thanks for the advice. I'll try to persuade the techie on Friday to look at the cabinet. I still think it could be the headend - I'm amazed at what people are prepared to put up with before complaining.

Cheers,
Steve

SteveDimond · 28-07-2008, 13:29

The VM tech came on Friday morning, and agreed with me that there was nothing wrong with my box and decided it was a network issue. He said he would contact network support.

On Friday afternoon two network techs in two vans came round to see me (I believe they had been checking the green cabinet in the road prior to their visit). They ran some tests, and came to the conclusion, as I already had, that the freezing was a transmission fault. They said they would contact the "head-end/Langley guys" and find out what was going on. However, they weren't very hopeful that the problem would get fixed unless others started complaining.

The problem was still there over the weekend. Is there some way I can find out what is happening with this issue? i.e. when/if the problem will be diagnosed and fixed? I'll certainly not get anywhere if I ring faults again - they'll not understand what I am talking about and will probably just send a signal to my box again or send out another VM tech.

Cheers,
Steve

Zain · 29-07-2008, 20:11

I have the same issue and i will try and ring them (the faults departments) tommorow im in the birmingham area and have constant loss of picture and quite a few stutters and freezes.

i'll keep you updated on my situation and i'll try and ask if i could get an update if it isnt fixed - cheers.