[no Bug] DVB-T Channel Scan unable to detect any channels (3 Viewers)

[mm1352000]

I presume that if I am doing an "all regions" scan, then this should find something?

Not necessarily unless the "all regions" frequency set contains the *correct* frequencies for your region. I'd be looking up the correct frequencies on your local government website (or wherever they are listed in the UK)...

I can not find this option in the card edit option!

Okay that is really not a good sign. Just to be sure that you're looking in the right place:
1. Open TV Server configuration.
2. Expand the "TV Servers" node.
3. Click on your TV Server (which will show the list of tuners in your PC).
4. Select the DVB-T tuner.
5. Click "edit" (WARNING: TV Server will automatically restart after you view these settings, so don't do this if you're recording something!).
6. Under "Adv. Tuning Options" you should see "when card enters idle state..." and then two options: pause and stop. You want to use "stop card (more compatible)".

It may be other information, I think that before I deleted all the channels prior to the retune problem, I am fairly sure that that MediaPortal reported "Channel not Available / No PMT Found" - could it be linked to this problem - https://forum.team-mediaportal.com/...540/channel-not-available-no-pmt-found-95854/ ?

If there was no PMT being broadcast then you certainly wouldn't find channels, but I think this issue is different...

 

[robbo100]

Re: DVB-T Channel Scan unable to detect any channels - FIXED

OK. I think I have sorted it!

I had previously used this site: Freeview on Sandy Heath TV transmitter | ukfree.tv - independent free digital TV advice to test some frequencies, however through random chance the ones I tried didn't work but tonight I have had time to try each one in turn and I have managed to get some channels tuned in within MP.

It looks like some of the tuning data may be wrong.

650200, 842000, 498000 and 522000 all work giving 52 TV channels and 23 radio channels.

626200 and 474200 are not working and those channels are missing. I will try to track them down and post the tuning details in the appropriate forum.

Probably best to put this a "No Bug" - thanks for all the help and sorry for the wild goose chase - but hopefully the new tuning details can go into 1.2 final to help others.

Robbo100

 

[jameson_uk]

yeah damn DSO is playing havoc with some UK frequencies and there are some interim frequencies which are a pain.

did scan all frequencies not pick up the channels?

 

[robbo100]

did scan all frequencies not pick up the channels?

No, only picks anything up when I scan a single frequency so I can only assume that those frequencies don't appear on any other UK transmitter (which seems odd).

Robbo100

 

[robbo100]

OK.

I think I have tracked them down now. The attached XML file includes all the current frequencies and also includes the future ones from after Nov 11, so it should be suitable for the 1.2 final release.

I have tested it on my system and it finds 90 TV and 25 Radio channels which is in the right ballpark - I haven't done a full check against the list of supposedly available channels, but a gross error check doesn't find major omissions.

Robbo100

 

[mm1352000]

Hi again robbo100

Thanks for following up - makes our lives as developers easier.

 

[jameson_uk]

Has a quick look and this could still be a bug or a different issue...
Most frequencies you have listed are in the all freq file so I am struggling to figure out why they are not picked up when scanning all channels.
Also you have

  <DVBTTuning>
    <Frequency>650200</Frequency>
    <BandWidth>8</BandWidth>
    <Offset>167</Offset>
  </DVBTTuning>

But this should be

  <DVBTTuning>
    <Frequency>650000</Frequency>
    <BandWidth>8</BandWidth>
    <Offset>167</Offset>
  </DVBTTuning>

The 200 is actually the 167 offset.

So removing the offset issue for a minute (these are marked as say C40+ on UK TV free), BBC One is transmitted on C27 with no offset and this is 522000 which is in the all freq file.....

Can you confirm that BBC One is not picked up using the all freq file. Assuming not can you confirm that your uk all region file does contain this frequency. Also can you scan this individual frequency manually. Does this pick up BBC One ?

For the offset frequencies could you try something similar. Can you scan 650000 manually, does this pick up ITV3, QVC etc?

 

[robbo100]

Jameson,

I am glad you wrote back as I was just about to post that although I have found the channels during the scan - I am having a terrible time actually watching them!

I can confirm that I can not find ANY channels using the "All Region" Scan and 650000 is definitely in the "All Regions" scan xml (it is the unedited one supplied with 1.2B).

When I try to view the channels after a scan using any fixed transponder .xml the channels are not viewable (times out on PMT), but if I do a single frequency scan then try to watch one of those channels then things are better... but the channel is usually locked in a 1 second loop of video and audio and never goes onto play the whole stream.

The revised .xml you linked to in an earlier post doesn't detect ANY channels, even though the frequencies are broadly the same as my self generated .xml file - which is confusing to say the least!

I have not got time to post full logs yet :sorry:, but attached are my TV Server logs for trying to view a channel after the "sucessful" tune using the xml I created (which found all the channels).

Also attached is a far less clean log which might have more information included.

I will do further fault finding tomorrow evening and post more structured testing logs.

Robbo100

 

[mm1352000]

Hi again robbo100

Your "messy" logs make for interesting reading!
Did you find that "stop graph" option in the card settings in the end?

 

[robbo100]

Did you find that "stop graph" option in the card settings in the end?

I presume you mean this section from the Wiki. I will try it tonight when I get back from work.

1.2.0 alpha:

Advanced tuning options
Allow this card to be preloaded
Pre-loading means that as soon as the TV-Service starts, a graph for the TV-Card will be created. This will reduce the time you have to wait when a TV-Card tunes a channel for the first time.
When card enters idle state do the following
The purpose of this feature is to reduce the time the TV-card needs to tune channels. It offers two options.
Pause card (default) - using this option will reduce the time your tv card needs to respond to your request to tune a channel.
Note: if you experience stability issues when turning this option on, then you have found a bug in the driver of your TV-Card
Stop card - using this option does provide performance improvements. It is only advised to use it in case that you experience stability issues with the "Pause card" option

Thanks

Robbo100

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Automerged double-post (edited by robbo to make it easier for others to read).


I managed to squeeze in some quick testing while scoffing breakfast before I left for work.

I changed the setting you suggested to “Stop” and did a re-scan (using the approved tuning xml file linked to by Jameson near the top of this thread). This time it managed to detect (some of) the channels correctly and then I was able to successfully display them.

I THINK what is happening is this:

If I have “Pause” set and I run a scan where the .xml file has unused frequencies within it, then once an unused frequency is scanned the card appears to “lock-up” for the rest of the scan and find no channels. The reason that my home made .xml seemed to work was because the unused frequencies (the frequencies where Sandy Heath channels will finally reside once all the transmitters surrounding Sandy Heath have all completed DSO) were all at the end of the .xml file whereas the official .xml file has one of those currently unused frequencies as the first entry of the .xml file. Therefore with my homemade .xml the card scan does not “lock-up” until the towards the end of the scan, once all the channels have been found. This is also why a manual single frequency scan seems to work fine and also why the “All Region” scan was failing.

With “Stop” set the DVB-T card does not “lock-up” after trying a channel-less frequency. Furthermore it also then allows me to view the channels reliably (subject to a more thorough stress test which I will do later).

I am still missing some channels as I believe that my home made .xml includes more of the current interim frequencies so I will fix the offset errors, re-test it on my system and then re-submit it for others to use.

Question: Is this an MP bug or a Pinnacle 300i driver issue? I never had this problem with 1.1.2 or earlier, but this “Stop/Pause” option was not available before. Should this option be set to “Stop” as a default setting during the installation of MP 1.2 (as it presumably was before 1.2) to maximise compatibility with DVB-T cards for all users?

Sorry I didn’t try the “Stop/Pause” option before now I got fixated by my sudden ability to tune-in some channels.