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Guest Message by DevFuse

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OTA Glitch Every 31 seconds


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17 replies to this topic

#1 OFFLINE   sregener

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Posted 21 June 2013 - 04:35 AM

I used to use a DTVPal DVR.  Every 31 seconds, the local ABC affiliate would have a picture glitch.  This was a known and reported bug in the DTVPal due to some incompatibility with the PSIP data sent by the local station.  They stopped updating the firmware, so there was no hope of ever getting it fixed.

 

Last night, I watched my local ABC station using the OTA adapter in my Hopper.  We're a couple years past the last firmware update to the DTVPal, it's a differrent box, etc. etc.  Yet there was exactly the same glitch every 31 seconds.  It usually presents as an artifact box in the picture, but occasionally the audio goes instead.

 

There is no glitch on the Dish LiL picture, but the compression causes artifacting and color squashing that make it less than desirable to watch.

 

I've tried contacting my local station to change their PSIP data, but they have been no help on this whatsoever.

 

Any advice?  Anyone else seeing this?



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#2 OFFLINE   P Smith

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Posted 21 June 2013 - 08:37 AM

Would be interesting to see a picture, here is a concern - if you see picture/audio distortion, then PSIP should not be the reason.

Secondary, it would be pretty easy to analyze stream and find out - you (or someone else in your area) could use OTA [USB/PCI/PCIe] tuner for PC with TSReaderLite and capture whole mux for a couple minutes.

 

We could continue detail discussion at AVSForum in DTVpalDVR thread.


Edited by P Smith, 21 June 2013 - 08:45 AM.


#3 OFFLINE   harsh

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Posted 21 June 2013 - 09:37 AM

Reminds me of a problem someone had with an electric fence back when. Every time the fence fired (I think it was every three seconds), the TV signal and the land line would glitch.

This may turn out to be an antenna grounding issue.

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#4 OFFLINE   KSbugeater

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Posted 21 June 2013 - 10:13 AM

For once, I'm on the same wavelength as harsh.  Electric fence (or some appliance, oscillating fan?) was my first thought.  30 sec is a long time for an electric fence, though.



#5 OFFLINE   PokerJoker

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Posted 21 June 2013 - 06:55 PM

I think I've heard of something similar happening from being too close to a doppler radar installation, although a 31 second sweep time seems a bit long.



#6 OFFLINE   P Smith

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Posted 21 June 2013 - 08:29 PM

slow rotating radar ?



#7 OFFLINE   sregener

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Posted 22 June 2013 - 02:00 AM

When I had the DTVPal DVR, I lived at a different house 20 miles away.  I had the exact same problem with the DTVPal DVR there that I have now.  The only two things in common are the station (KAAL TV, Austin, MN) and Dish hardware/firmware.  At the old address, I bought an AM21 tuner because I was on DirecTV, and the problem was instantly solved.  When it isn't storming, I can hook the antenna cable up to the TV's tuner if it will really convince anyone that the problem is in the Hopper's OTA code and not the antenna installation or other local factors, but I know what I'm seeing.  It really is different from other reception artifacts.



#8 OFFLINE   P Smith

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Posted 22 June 2013 - 09:26 AM

you are starring at wrong suspect ...

 

if Pal and H exhibit same behavior (eg different devices and different FW) in two different places, then the issue is outside, not in a the box



#9 OFFLINE   sregener

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Posted 22 June 2013 - 04:51 PM

P Smith, your logic does not follow.  If I found a security hole in Windows 95 on one PC, and then later bought a new PC with Windows 98 on it that had the same security hole, while the hole did not exist on my Linux boxes, your logic would state that the problem must not be Windows itself.  Rather, it is the common code between the two that makes the same security hole present on both Windows machines.

 

I am an expert troubleshooter.  I can divide most problems up quickly and resolve them.  In this case, we have a simple problem comprised of two parts.  1) Dish's code that interprets PSIP data (which I believe the be common between the DTVPal DVR and the Hopper, though I have no proof of this) and 2) A PSIP encoder that some ABC stations across the nation used a few years ago and some still use.  Now, if you don't have a station with that PSIP encoder, then you won't see the problem.  And if you don't use a Dish receiver with the firmware bug, you won't see the issue.  That's how I'm easily able to fix the glitch - I just stop using a DTVPal or a Hopper for my OTA viewing and the problem is fixed.  This is not ideal, though, as I don't want to switch back to DirecTV to fix a firmware bug, when I had nightmares with DirecTV's DVRs.

 

I disconnected my antenna from the Hopper, plugged it into the television and watched several minutes of artifact-free viewing on KAAL-TV.  I then unplugged the antenna cable and put it back into the Hopper, and was easily able to detect the artifact problem.  I also watched KAAL via Dish's HD LiL service, and the artifacts did not appear.

 

What makes this artifact so distinctive is both its regular timing, and it's appearance.  When it impacts audio, it is the briefest of glitches - you might miss a syllable.  But when it's in the video portion of the signal, it only appears in one tile.  If you don't know what tiles are in MPEG2 encoding, then you probably don't know enough to troubleshoot this problem.  It's there for a fraction of a second, and then it's gone.  I much prefer the video artifacts to the audio ones, but I don't get to choose where this particular PSIP glitch occurs.



#10 OFFLINE   P Smith

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Posted 22 June 2013 - 06:42 PM

it's came to useless verbal exercice, sorry

 

you don't know what is PSIP and what is video/audio PES, but making conclusion, wrong conclusion

 

as I recommend - find a way to store a few minutes of the station's mux and start analyzing... you will get grasp of PSIP, video/audion streams, etc

but now, please, lets stop this discussion



#11 OFFLINE   sregener

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Posted 23 June 2013 - 04:47 AM

P Smith, you state that the problem must not be within the Dish receiver.  So explain to me why I only see the problem with Dish-branded equipment but not with my TV's internal tuner or a DirecTV OTA tuner module.  The onus is on you to explain your reasoning.

 

I am not an expert on acronyms.  I do know what I read in the DTVPal DVR known issues thread on AVSForum, and the 31-second artifact was a known bug that was an incompatibility with the PSIP data sent by some encoder at certain stations.  Seeing the same artifacts (visually, it is usually a small rectangle of mostly green and black blocks) using a Hopper, I suspect the code was copied and the bug remains.  Asking whether anyone else saw it seemed reasonable to me, but I guess it's not.  I'll just have to open a ticket with Dish and hope that it gets fixed, but I am not optimistic, since so few people are impacted by it.



#12 OFFLINE   P Smith

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Posted 23 June 2013 - 10:30 AM

well, could you give me an URL to that original post, please ? perhaps you know I'm spending a lot of time there  ...

 

just to make your picture more realistic: a code [FW] for Pal DVR written by UK ppl (e* Eldon branch) separately and for different HW [a core is STM STi7109] using ATSC simulators (as you know, UK using DVB-T/T2 World standard for OTA) while Hop and other USA endemic boxes serving by other SW team, here in US; these guys fortunately has direct access to natural airways with real OTA environment include multipath, interference, PSIP oddities from US stations, etc


Edited by P Smith, 23 June 2013 - 10:31 AM.


#13 OFFLINE   sregener

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Posted 23 June 2013 - 05:20 PM

http://www.avsforum....tvpal-dvr-topic

 

Item #12: Audio/Video dropouts every 30-32 seconds on certain channels.

The DTVPal DVR exhibits A/V dropouts every 30-32 seconds on some channels. This appears to be an incompatibility between the DTVPal DVR and the encoder and/or PSIP settings used by some broadcasters. This is not a common issue.



#14 OFFLINE   P Smith

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Posted 23 June 2013 - 06:54 PM

Perhaps you pull 3 years old report, you should get back to that place where you got response from jrastore http://www.avsforum....at AVSforum ...



#15 OFFLINE   sregener

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Posted 24 June 2013 - 04:16 AM

What exactly do you want me to do about that response?  It doesn't apply to me because my local ABC affiliate does not upconvert to 1080i.  And even if they did, the engineers at the local station have been unresponsive to this issue.  In one sense, it is understandable, because they are in a small market and are undoubtably on a tight budget.  Yet it leaves me with a sour taste in my mouth because this problem is obviously a 2-sided problem and it makes no sense that out of the hundreds of tuners out there, only the Dish ones seem to choke on it.  So ultimately, I'm asking the local ABC affiliate to work around a programming flaw they had nothing to do with.  Doesn't quite seem fair, does it?



#16 OFFLINE   P Smith

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Posted 24 June 2013 - 10:46 AM

we are circling now - see post#2



#17 OFFLINE   Jhon69

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Posted 25 June 2013 - 11:08 AM

What exactly do you want me to do about that response?  It doesn't apply to me because my local ABC affiliate does not upconvert to 1080i.  And even if they did, the engineers at the local station have been unresponsive to this issue.  In one sense, it is understandable, because they are in a small market and are undoubtably on a tight budget.  Yet it leaves me with a sour taste in my mouth because this problem is obviously a 2-sided problem and it makes no sense that out of the hundreds of tuners out there, only the Dish ones seem to choke on it.  So ultimately, I'm asking the local ABC affiliate to work around a programming flaw they had nothing to do with.  Doesn't quite seem fair, does it?

 

 

 I upconvert my local ABC affiliate to 1080i with the HD settings in Menu,also suggest you split your signal with a dual splitter.It works very good to have an OTA signal going to the HDTV and DVR.Good Luck! with your other problem sounds like it is picking up a pulse from somewhere.I do not see this issue where I live so I indeed wish you the best in overcoming your problem.


Edited by Jhon69, 25 June 2013 - 11:16 AM.


#18 OFFLINE   thomasjk

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Posted 25 June 2013 - 12:09 PM

I also don't see any issue like this with my Hopper and the local ABC station.






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