TV Server always gives "no signal" when scanning (1 Viewer)

stephenlamppost

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February 15, 2011
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MediaPortal Version: 1.1.2
MediaPortal Skin: default
Windows Version: XP SP3
CPU Type: Pentium 3 Tualatin 1.4GHz
HDD: Western Digital 200GB PATA....
Memory: 256MB
Motherboard: Asus TUSL2-C
Video Card: Matrox G400
Video Card Driver: 5.96.4.0
Sound Card: Zoltrix Nightingale (C-Media 8738)
Sound Card AC3: er, yes
Sound Card Driver: 5.12.1.630
1. TV Card: Twinhan (VisionPlus) PCI
1. TV Card Type: DVB-T
1. TV Card Driver: 1.2.1.9
MPEG2 Video Codec: nothing I've installed specially
MPEG2 Audio Codec: same
h.264 Video Codec: same
Satelite/CableTV Provider: UK free-to-air DVB-T
HTPC Case: Asus Vento tower
Cooling: big Zalman copper heat-sink, no fan
Power Supply: Q-Technologies 400W quiet PSU
Remote: VisionPlus bundled one
TV: Samsung SyncMaster 940MW
TV - HTPC Connection: VGA

Firstly, thanks to everyone involved in MediaPortal -- although it doesn't quite work for me yet, I can tell it's the product of a lot of hard work by a lot of people.

My problem is that I can't watch TV with my Twinhan DVB-T PCI card. Scanning for channels *almost* always fails with "No signal". This is using the TV Server configuration app, selecting the server and card, choosing the appropriate regional transmitter settings (UK - Oxford) and clicking "scan".

I know that my card and drivers work, because I can watch TV in VLC just fine by entering the right frequency manually. I can also see that the TV server scan is trying all the right frequencies. The "signal level" and "signal quality" bars stay at zero the whole time, and a red "No signal" message appears for each mux in turn.

I say "almost always" because I did *once* get it to tune in successfully to a couple of muxes. This occurred when I'd just been fiddling with a few settings: the "tune (seconds)" setting (in General Settings -> Scan; I increased it to 5), "linkage scanner" (turned on, was off) and "delay in seconds before TVServer detects cards" (set to 3). However, it only worked for the first two muxes, then did the usual "no signal" thing for the others. And even worse, without changing the settings from the apparently successful values, subsequent tuning attempts keep failing, *even* for the muxes that had worked the one time. Some channels are now in the channel list, but I can't watch them in MediaPortal -- no signal, again. I have tried some other values for the settings I fiddled with, but have had no luck.

One observation is that the server doesn't appear to be waiting very long before moving to the next frequency -- a few seconds at most, and less when trying the +/-167kHz alternatives. It doesn't seem to matter how many seconds I choose for "tune" in the settings. On the successful run, it seemed to spend longer on the frequencies that worked, although that's probably because it got a signal lock and was busy reading the channel info.

I've attached a log that has several failing runs and, also, the only two successful tunings. The first successful tuning is at 00:19:29, and the second (and final) one is at 00:19:52. All the others I've ever tried have failed.

I get this bug with version 1.1.2 of MediaPortal. But note that this log is generated by MediaPortal 1.0.2, because I've been experimenting with older versions to see if the bug is a regression. I really do get exactly the same bug with 1.1.2 -- I can post logs for that too if you like, but 1.0.2 just happens to be what I have installed right now, and the successful tunings in this log may be useful.

Thanks for reading, and for any help. I'm quite enthusiastic about getting MediaPortal up and running, so if a fix emerges for this bug, and one other that is a showstopper for my using MediaPortal (I'll post a separate report in due course), I'll be keen to make a donation to the project.

PS: I'm using the Twinhan 1.2.1.9 driver because 1.2.3.8 hard-locks my machine *extremely* reliably. From using other applications, I know that 1.2.1.9 works nicely and seems to be regarded as the most stable by a lot of users. Also, I know my hardware is old! But it's easily sufficient for standard-definition video, and it's quiet, and it works.
 

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  • tv-log-no-signal-except-001929.txt
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mm1352000

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    Hi and welcome to the forum :)

    We should be able to get this card working. First I'd suggest you do a complete uninstall, and then reinstall 1.1.2 - using 1.0.2 won't solve the problem, and it will make it harder to help you. After you've done that, please provide *full* TV Server logs showing a full DVB-T scan for your region. It would help if you could delete your logs (in C:\Documents and Settings\All Users\Application Data\Team MediaPortal\MediaPortal TV Server\log) before you start the scan. Also just in case you weren't aware, tuners can only be used in one application at a time, so make sure VLC etc. are closed before trying to scan in MediaPortal...
     

    stephenlamppost

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    Thanks for this (and for the welcome!). I've now done a complete uninstall and installed 1.1.2. Here's a clean set of TV Server logs for a single scan of all six muxes in my area.

    Thanks for the suggestion -- but yes, I have not had VLC running while scanning. And just for completeness, I forgot to mention that I have of course installed the dvbfix (and did so after my DirectX install).
     

    jameson_uk

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    There appear to be some odd tuning details in your logs
    (578000, 577833, 578167 are all really the same frequency with a +/- 167 offset)
    Not at a machine to check now but I will have a look at the Oxford tuning details as this looks odd.

    Can you confirm what transmitter you get your TV from? Is this actually the Oxford transmitter or is there a local small transmitter?
     

    mm1352000

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    Hi again

    I used to use an OEM Twinhan tuner, and as I recall it had a registry flag that controlled whether the offset was automatically scanned or not. I know in the new XML tuning detail scripts there is also an offset attribute but I'm not sure how it is applied - I guess it must be at scan time. You want to make sure that the registry flag and the tuning offset don't combine to put the frequency 167 MHz out...

    Are you ever scanning after resuming from hibernate/standby? The fast scan indicates an error in scanning - perhaps that the hardware is not found (which sometimes happens to me) - and yet you didn't post an error log. There wasn't any error log in the TV Server log folder was there?
     

    stephenlamppost

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    Thanks for both of these responses. For the strange frequencies, I'm fairly sure that this is correct -- many UK muxes are broadcast at a 167kHz offset from the centre of the channel. I can't remember where I learnt this, otherwise I'd post a link. However, the scan is trying all three possibilities in turn (no offset, positive, negative) so I think it is sure to try the right frequency. I am only a mile or so out of the city of Oxford, so fairly sure I get the Oxford transmitter. In fact I just checked on Digital UK - Home and it says I do -- although I can't be sure it knows about smaller local transmitters if they're on the same frequencies. (If you put your postcode into that site and click "I am in the aerial installation trade", it gives you a full chart of channel numbers by mux and transmitter, with a "+" or "-" in certain cases which I'm fairly sure indicates the 167kHz offset.)

    Suspend/resume: I've definitely had this bug from a clean boot, although I do use suspend/resume quite a bit. I'll double check shortly that this still happens when I do a cold boot, but I'm sure I've tried that many times. The registry flag sounds interesting (can you remember any more details? googling the obvious doesn't turn up much). On the other hand, I can tell by watching the scan that it is trying the correct frequencies (i.e. ones that work in VLC) so perhaps that isn't the problem.

    The problem I mentioned with the scan not taking as long as it should seems to be fixed with 1.1.2 -- if I crank up the tuning time to something high (12s when I just scanned), spends roughly that long on each frequency before moving on.

    There is no error log (or actually, there is but it's completely empty, zero bytes) -- the logs I attached are the only non-empty non-backup logs in my log directory (except for today's TsWriter log that just appeared).

    Thanks for your persistence!
     

    jameson_uk

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    Thanks for both of these responses. For the strange frequencies, I'm fairly sure that this is correct -- many UK muxes are broadcast at a 167kHz offset from the centre of the channel.
    Agreed but was the under the impression that the offset was included in the tuning details file and it would only scan the correct one (not at home to check though)

    I had an issue a while ago with offsets not being applied (0002492: DVB-T scanning doesn't scan frequency offsets properly - MediaPortal Bugtracker) but this would suggest that we do try the main freq then +/- offset so that is probably a red herring.

    I did have a quick look at a copy of the Oxford tuning details last night and they appear to be ok (and the freqs scanned in your logs)

    Can you try Standalone DVB-T Signal Strength/Quality Utility - Hauppauge UK Forum (User -> User Support) and see what that comes up with (I am assuming the card does have a BDA driver as is not dealt with differently in MP (MM?))
     

    mm1352000

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    I am assuming the card does have a BDA driver as is not dealt with differently in MP (MM?)
    Yep, Twinhan tuners are supported as regular BDA tuners with additional manufacturer-specific support for DiSEqC and viewing of encrypted channels (with an appropriate CAM). There is nothing that should stop the tuner from working unless there is a local signal problem or the wrong frequencies are being scanned.

    Regarding the registry setting: I found a range of tuner settings in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E96C-E325-11CE-BFC1-08002BE10318}\0020\ in a folder called "DriverData[x]". I'm pretty sure the "0020" is simply because the tuner was the 20th device that I installed, so that number will probably be different for you. [x] is definitely the tuner number on the card - I was using a 2xDVB-T + 2xDVB-S device, so there was a setting in DriverData0 and DriverData1. There are copies of the settings under ControlSet001 and ControlSet002. In this case I think the ShiftFreqScan key is the what we'd be interested in...

    Having said that, I'd *really* recommend that you leave all of the registry settings alone unless you get really desperate. Better to exhast all other options first...
     

    stephenlamppost

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    Thanks for this -- I just had a go with ScanChannelsBDA and it seems to have a problem too. It seems to lock on to the right frequencies, but then fail (I'm not sure what this bit of the "scan", after locking on, is doing exactly). I've attached the log.

    Thanks for the registry key details too! Agreed that fiddling with this is a last resort, but could conceivably be useful.
     

    mm1352000

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    Hi again

    Did you see a message like "# locked on <frequency>KHz, please wait for network information..."?
     

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