Gradual Degradation of 1 TV Channel / Continuity Errors (1 Viewer)

[Peter Mee]

I have a problem whereby a particular channel degrades gradually over a period of about an hour to the point where it's just a black screen with intermittent audio.

I have a single-seat installation of MP 1.5.0 on an Q6600 Quad Core CPU. I use Digital Devices Octopus / DuoFlex to tune both DVB-T and DVB-S2 signals, all free to air.

Yesterday, I was watching some sport on one of the DVB-T channels, (HD). All was fine for about 45 mins then some infrequent pixelation and stuttering appeared. Maybe a couple of seconds every couple of minutes. This continued and escalated in severity and frequency over the next 30 minutes to the point where the channel was unwatchable (constantly breaking up). Later, this progressed to a completely black screen and intermittent audio.

Having left the situation overnight, the channel is now back working again.

This happened several weeks ago on the same channel but I put it down to weather conditions on the day. Yesterday, however, was a fine day and no other channels on the same multiplex were affected.

Here's everything I've tried without success;

-Stop live TV and start it up again inside mediaportal.
-Quit mediaportal and restart
-Shutdown computer and restart
-Change TV codec
-Change timeshift folder to alternate drive
-Add 'RelaxTsReaderForBadReception.txt. file to drive root

I've attached log files generated when the problem was manifest. Is note that the TSReader file is full of Video Continuity errors.

I tried recording the problem channel but the recording exhibits the same problems. No other channels on either tuner exhibit these issues while this is happening.

Any advice appreciated. I'm about to dump my satellite provider in favour of a MP solution but this is a heavily watched channel in our house and I cannot really afford to not have it reliable.

Thanks in advance

Peter

 

[mm1352000]

Hello Peter

Mentioning the name of the channel would be good.
If I guess that you're referring to "RTÉ Two", would I be correct?

I see continuity errors in the TsWriter log file so the problem is clearly server-side. Probably either signal quality or HDD stress. None of the things you've tried except maybe moving the timeshift folder and restarting the PC would have any effect.

Whenever you tune channels that are on the same frequency as "RTÉ Two" (for example, "3e", "TV3" and "RTÉ News Now") I see continuity errors in the log. Therefore I find it a little difficult to believe this:

No other channels on either tuner exhibit these issues while this is happening.

I can see that you don't seem to have any problem with "RTÉ One"... but that is a different frequency/multiplex.

Please use Task Manager->Performance Monitor to check your HDD utilisation while timeshifting to confirm that the HDD is not stressed. Real time scanners (virus, anti-spyware protection) can cause problems if they scan the TV Server and/or MP timeshift, record and program folders.

Please check your signal quality: aerial alignment, cabling, connections.

mm

 

[Peter Mee]

Thanks for the quick response.

Apologies for not identifying the channel, it is rte two.

I can confirm all other channels on the multiplex play fine. Rte two is the only hd channel on this multiplex, if that makes any difference.

Looking at the disk performance, there don't appear to be any issues and nothing odd compared to any other channel (<10% active time and everything else within acceptable parameters). There are no anti-virus or similar real time scanners enabled.

Mp reports excellent signal level and quality on the channel. Unfortunately I don't have any other dvb-t equipment to conduct a comparison but will try to borrow some this week to check if similar problems exist with other types of tuner.

If there are any other ideas on what I could check, they would be greatly appreciated.


Peter

 

[mm1352000]

I can confirm all other channels on the multiplex play fine. Rte two is the only hd channel on this multiplex, if that makes any difference.

Yes, HD does make a difference. More bits => more chance of corruption. If you were to disable the TsReader "don't drop discontinued packets" option then you'd probably notice.

Looking at the disk performance, there don't appear to be any issues and nothing odd compared to any other channel (<10% active time and everything else within acceptable parameters). There are no anti-virus or similar real time scanners enabled.

Okay.

Mp reports excellent signal level and quality on the channel. Unfortunately I don't have any other dvb-t equipment to conduct a comparison but will try to borrow some this week to check if similar problems exist with other types of tuner.

Actually, I was going to say that your signal quality readings seem a little low for a DD tuner. I've never used one myself but I've seen plenty of logs and from what I can remember, you should expect 100/100 all the time. In your case I see you have 100/~80 or 100/~90 for strength/quality. Also, in your system event log I see plenty of entries like this:

"17/11/2013 08:49:56";"DDCapture";"(0)";"Warning";"Device (010:40000) Stream 5 dropped data";"2148007948"

I'm not 100% sure what this means but I think it could mean bad signal quality. You can ask Digital Devices support.

If there are any other ideas on what I could check, they would be greatly appreciated.

The other possible causes of continuity errors are much more rare and "exotic". Things like overheating tuner components, CAM issues, motherboard compatibility issues, bad SATA or CI cables etc. Based on the current evidence, I think it is more likely that you have signal quality issues. I suggest you find out what the DDCapture message means first and then go from there.

mm

 

[Peter Mee]

So I figured this out and thought I'd post for future head scratchers....

I managed to obtain a TV with DVB-T tuner to try to establish if I had a signal or hardware problem.

Plugged in the TV, hit auto-tune and ended up with all channels across 2x multiplexes (30 & 58) set up perfectly with 100% signal and quality levels.

Since my issue was only with channels on multiplex 30, I looked at that in more detail. Those channels on the TV were coming in at frequency 542MHz. When I checked the same channels on MP, they were tuned on 778MHz (multiplex 58 is on 770MHz).

I manually changed the frequency for all of the problem channels (778 -> 542) and they displayed perfectly.

So, is it the case the MP tunes to the highest/last frequency a channel appears at, even if channels are present on lower frequencies with better signal strength & quality? Will I need to make this manual alteration whenever I need to retune?

(now I need to figure out why my DVB-S2 tuner has disappeared from my system - must have knocked something out of whack...)

Peter

 

[mm1352000]

Hello again Peter

So, is it the case the MP tunes to the highest/last frequency a channel appears at, even if channels are present on lower frequencies with better signal strength & quality?

Yes, it probably is. We don't expect people to pick up duplicate channels in this way.
Having said that, in your log files I can see you do a DVB-T scan... and I don't see 542 MHz being scanned. What country/region are you scanning? Is it possible that you picked the wrong region, or could the tuning details for your region be out of date? If the details are out of date or missing, we'd really appreciate an updated frequency list. These can be posted here:
https://forum.team-mediaportal.com/forums/submit-epg-grabbers-and-tuningdetails.296/

Will I need to make this manual alteration whenever I need to retune?

Depends on what actually happened. I don't think 542 MHz was actually scanned, so I think a tuning detail file update would solve the problem.

mm

 

[mm1352000]

In fact, it looks like somebody else had a similar problem...
https://forum.team-mediaportal.com/...-might-help-others.122355/page-2#post-1042848

Maybe you could verify these?
https://forum.team-mediaportal.com/threads/updated-dtt-frequencies-for-ireland.122916/

 

[Peter Mee]

Many thanks for the responses.

I'm scanning Ireland - Three Rock and it seems that I have the exact same issue as the poster in the other thread you reference: Incorrect tuning details.

When I have a chance, I'll check the posted updated files and revert though from what he says, I expect they would be correct.

Peter