Missing Channels (1 Viewer)

Kyle S.

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December 29, 2012
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Hi, I am having a problem locating some clear QAM channels from my local cable provider (Time Warner Milwaukee). I know the channels exist because my built-in tuner within the tvs around the house are able to find and display them fine.

Doing a new scan with my new HVR-2250 cards on "Clear QAM standard" locates the channels and even populates the channel name in the list ie. "WMVS HD" (which does match the channel display on the tv's). But when I want to preview them or watch them within MP, I get a "Preview Failed:NoPMTFound" or a "NoSignalDetected". A few of the channels work, and some are buried in channel names like "Unknown 118-90" - but even these are at standard definition, not HD like I was looking for.

Something else that I noticed, the signal level always reads "0" but the signal quality is pegged at "100". I have a drop amp splitting the cable. The tuner card should be seeing the same signal strength as all the other TV's in my house (which have no tuning problems). I read somewhere that this might be a card driver bug?

To summarize again, the TV is able to find and display the channels in HD (so I know they are there), but my tuner card cannot.


Thanks for the help everyone.
 

mm1352000

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    Hello and welcome Kyle :)

    I think I see the problem.
    Some of the channel information - specifically, the frequency - that TV Server is receiving from TW is bogus.

    The following channels are affected:
    • MYSTRO
    • WMVT HD
    • Jazz
    • V-me
    • WORLD
    • Create
    • Classic
    • Weather
    • Traffic
    • WMVS HD
    • WITI-DT (6-1)
    • WITI-DT (6-2)
    • WTMJ-DT
    This may be a dumb question (please cut me some slack - I'm based in NZ and have little idea how US cable TV works! ;)): do you have a tuning adaptor (TA)?
    If the answer were yes, it might explain the problem.
    If the answer is no, getting TW to fix this from their end would be the correct solution (but I suspect that may be an exercise in futility). They probably "forgot" to update the frequencies last time they moved the channels around.

    It is possible to fix this manually from your end.

    1. Open TV Server configuration.
    2. Go to the TV Channels section.
    3. Select one of the above channels and click edit. You should see something like this:
    http://wiki.team-mediaportal.com/1_...or_Edit_a_Channel#Editing_an_existing_channel
    4. Select the tuning detail (the row in the bottom area) and click edit.
    5. Fix the frequency as per the following details:
    • MYSTRO
      • incorrect scanned frequency = 622250 kHz
      • correct frequency = 601250 kHz
    • WITI-DT (6-1), WITI-DT (6-2), WTMJ-DT
      • incorrect scanned frequency = 577250 kHz
      • correct frequency = 229262 kHz
    • (all others - WMVT HD etc.)
      • incorrect scanned frequency = 583250 kHz
      • correct frequency = 763250 kHz
    6. Click OK then OK again to finish editing the channel.
    7. Repeat for all the channels listed above.

    Note: if you rescan, you'll probably have to do this again.

    Sorry for any frustration caused.

    mm
     

    Kyle S.

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    Wow, that did the trick. I certainly appreciate your attention, even from all the way around the world. Not sure what a tuning adapter is. For paid cable subscriptions here, we have a "cable tuner box" which decrypts the scrambled channels. In my case, I am coming right from the wall, right into the the tuner card to capture the unscrambled signals. The cable companies in the US are required to broadcast the local over the air stations on the cable system in an un-encrypted format (Clear QAM)

    Just so I understand... The card locks on to a specific frequency for tuning finds a signal, and grabs the station name and other tuning in formation from the stream. You are saying that the tuning info pushed from the cable company is incorrect? I am curious why MP trusts the pushed info instead of what the card is actually tuning to? (which led me to this point?) Because a built in "dumb" tuner in the tv is able to handle this situation without problem.

    And for my own education, where specifically in the logs did you find the channels that were bad? And how did you determine the correct tuning frequencies?
    This whole digital broadcasting is a whole lot more difficult for me to understand than the old analog system (physical channels, sub-channels, virtual channels ..etc..)

    Again, thanks for the help.
     

    mm1352000

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    Hello again Kyle

    Wow, that did the trick.
    Great! :)

    Just so I understand... The card locks on to a specific frequency for tuning finds a signal, and grabs the station name and other tuning in formation from the stream. You are saying that the tuning info pushed from the cable company is incorrect?
    Yes, that's right.

    I am curious why MP trusts the pushed info instead of what the card is actually tuning to? (which led me to this point?) Because a built in "dumb" tuner in the tv is able to handle this situation without problem.
    That is a very reasonable question. :)
    The answer: sometimes the cable company will push the information for all their services ("channels") on one or all frequencies. This enables a tuner to tune 1 frequency to find all available services rather than tuning 150+ frequencies to find the services available on each frequency. The first approach might take 30 seconds while the second might take 30 minutes.

    Notes for the first approach:
    • the cable provider has to push the frequency details with each service for it to work
    • a tuner may be tuned to a given frequency and receive info for services which are carried on different frequencies
    Notes for the second approach:
    • the tuner only receives info for services which are carried on the currently tuned frequency, and therefore service frequency always equals tuned frequency
    MediaPortal supports both approaches. At present MP isn't smart enough to determinel which approach the cable provider is using so it is forced to trust the information received from the cable provider. As it happens, your provider uses approach two and pushes some bogus info. Hence the problem.

    I have an idea for how to work around this problem. It will just take some time to implement.

    And for my own education, where specifically in the logs did you find the channels that were bad? And how did you determine the correct tuning frequencies?
    The TVService.log file. Here is an example:
    [2013-11-13 06:42:23,493] [Log ] [19 ] [INFO ] - atsc:Tune:ATSC:tv: Freq:229262 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 phys:25 maj:-1 min:-1 mod:Mod256Qam
    [2013-11-13 06:42:23,493] [Log ] [19 ] [INFO ] - atsc:using new channel tuning settings
    [2013-11-13 06:42:23,493] [Log ] [19 ] [INFO ] - dvb:confused:ubmiting tunerequest Channel: subChannel:0
    [2013-11-13 06:42:23,493] [Log ] [19 ] [INFO ] - dvb:Getting new subchannel
    [2013-11-13 06:42:23,508] [Log ] [19 ] [INFO ] - dvb:GetNewSubChannel:0 #0
    [2013-11-13 06:42:23,618] [Log ] [19 ] [INFO ] - TvDvbChannel ctor new subchIndex:0
    [2013-11-13 06:42:23,618] [Log ] [19 ] [INFO ] - dvb:confused:ubmit tunerequest size:1 new:0
    [2013-11-13 06:42:23,618] [Log ] [19 ] [INFO ] - subch:0 OnBeforeTune
    [2013-11-13 06:42:23,696] [Log ] [19 ] [INFO ] - dvb:confused:ubmit tunerequest calling put_TuneRequest
    [2013-11-13 06:42:23,696] [Log ] [19 ] [INFO ] - dvb:confused:ubmit tunerequest done calling put_TuneRequest
    [2013-11-13 06:42:23,696] [Log ] [19 ] [INFO ] - subch:0 OnAfterTune
    [2013-11-13 06:42:23,696] [Log ] [19 ] [INFO ] - RunGraph
    [2013-11-13 06:42:23,711] [Log ] [19 ] [INFO ] - subch:0 OnGraphStart
    [2013-11-13 06:42:23,711] [Log ] [19 ] [INFO ] - dvb: RunGraph
    [2013-11-13 06:42:24,352] [Log ] [19 ] [INFO ] - dvb: LockInOnSignal ok
    [2013-11-13 06:42:24,352] [Log ] [19 ] [INFO ] - subch:0 OnGraphStarted
    [2013-11-13 06:42:24,352] [Log ] [19 ] [INFO ] - subch:0 SetupPmtGrabber:pid FFFFFFFF sid:FFFFFFFF
    [2013-11-13 06:42:24,352] [Log ] [19 ] [INFO ] - subch:0 SetupPmtGrabber:pid FFFFFFFF sid:FFFFFFFF
    [2013-11-13 06:42:24,414] [Log ] [19 ] [INFO ] - Scan: tuner locked:True signal:0 quality:100
    [2013-11-13 06:42:25,211] [Log ] [19 ] [INFO ] - 0) 0x6 0x277F 0x3E 0x0 WITI-DT type:2
    [2013-11-13 06:42:25,227] [Log ] [19 ] [INFO ] - atsc:Found: ATSC:tv:Cable WITI-DT Freq:577250 ONID:6 TSID:10111 SID:62 PMT:0x0 FTA:True LCN:6002 phys:83 maj:6 min:2 mod:Mod256Qam
    [2013-11-13 06:42:25,243] [Log ] [19 ] [INFO ] - 1) 0x9 0x277F 0x2 0x0 WITI-DT type:2
    [2013-11-13 06:42:25,258] [Log ] [19 ] [INFO ] - atsc:Found: ATSC:tv:Cable WITI-DT Freq:577250 ONID:9 TSID:10111 SID:2 PMT:0x0 FTA:True LCN:6001 phys:83 maj:6 min:1 mod:Mod256Qam
    [2013-11-13 06:42:25,274] [Log ] [19 ] [INFO ] - 2) 0x10 0x277F 0x1 0x0 WTMJ-DT type:2
    [2013-11-13 06:42:25,274] [Log ] [19 ] [INFO ] - atsc:Found: ATSC:tv:Cable WTMJ-DT Freq:577250 ONID:16 TSID:10111 SID:1 PMT:0x0 FTA:True LCN:4001 phys:83 maj:4 min:1 mod:Mod256Qam
    [2013-11-13 06:42:25,274] [Log ] [19 ] [INFO ] - Scan Got 3 from 3 channels

    The tuner tuned to 229262 kHz; the channels were saved with frequency 577250 kHz.
    For you, the correct frequency is the tuned frequency; the sometimes-incorrect frequency is the saved frequency.

    This whole digital broadcasting is a whole lot more difficult for me to understand than the old analog system (physical channels, sub-channels, virtual channels ..etc..)
    Heh, yes - no argument from me there! :)
    For what its worth, here is my understanding...
    For US ATSC and cable, a physical channel is a 6 MHz "slot" at a given frequency. In the above example, physical channel is 25. Range is from 228000 kHz to 234000 kHz.
    The sub-channels are the services carried in a physical channel. In the above example, that is WITI-DT (25-2), WITI-DT (25-62) and WTMJ-DT (25-1). The bracketed numbers are QAM channel numbers (format: <physical channel>-<service ID>).
    Virtual channel numbers are the numbers that you press on your remote control when you want to tune a channel. ATSC has two-part channel numbers. In the above example there are two WITI-DT's - 6-1 and 6-2 - and WTMJ-DT which is 4-1.

    Again, thanks for the help.
    Happy to help. :)

    mm
     

    Kyle S.

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    Cool, understood.

    Yeah, maybe an option for an "exhaustive" channel scan would fix the problem (similar to what my tv tuner does by default - 30+ minute scan time)

    Thanks again, hugely helpful.
     

    Kyle S.

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    Hello again. Looks like the cable company switched a whole bunch of things up just to keep me on my toes.

    The automatic channel scan was able to pick up about 1/2 the digital channels that my regular tv can find. I have the same setup, HVR-2250 as mentioned in the original post. I searched through the logs like was described in the reply and attempted to apply the same fix which previously worked - "manually change the tuned frequency in the channel tuning details". Alas, I can not get these channels to come in. I get a "NO PMT FOUND" error.

    Attached is the tv service log. the channel I am working on is WDJT-HD, but I think all the channels on the frequency are missing. (the tuning section in the the log is @ 2014-09-14 09:34:19,697)

    I have been fiddling around with the ONID, and service ID etc... with no progress.

    Thanks in advance for the help.
     

    mm1352000

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    Hello again Kyle

    For WDJT-HD...
    Here are the scanned details:
    [2014-09-14 09:34:20,597] [Log ] [31 ] [INFO ] - 1) 0x7 0x23B5 0x5 0x0 WDJT-HD type:2
    [2014-09-14 09:34:20,597] [Log ] [31 ] [INFO ] - atsc:Found: ATSC:tv:Cable WDJT-HD Freq:589250 ONID:7 TSID:9141 SID:5 PMT:0x0 FTA:True LCN:58001 phys:85 maj:58 min:1 mod:Mod256Qam

    As before, the correct details are the tuned details at the time the channel was found:
    [2014-09-14 09:34:19,697] [Log ] [31 ] [INFO ] - atsc:Tune:ATSC:tv: Freq:163250 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 phys:21 maj:-1 min:-1 mod:Mod256Qam

    The only thing you should do to make WDJT-HD work is change the physical channel number from 85 to 21 and the frequency from 589250 to 163250.
    Do not touch anything else such as the ONID or service ID - they are already correct, so if you change them you're making the problem worse.

    Regards,
    mm
     

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