Channel tuning broken with DVB-C
- 1 Whats wrong ?
- 2 How can we fix it ?
- 3 Broken providers
- 3.1 Netherlands
- 3.2 France
- 3.3 Germany
- 3.4 Denmark
Whats wrong ?
With some cable providers scanning for channels seem to work fine, but its not possible to tune the channels. Two problems are known:
1. Some provider change the modulation of satellite feeds for DVB-C but don't modify the device information. One have to scan each frequency manually but there is no way around it.
2. These providers have different regional channel lineups but generate the SI in a central place. They transmit for each region one NIT all the time. The DVB standard has a flag to indicate whether a NIT is for the actual network or for an other network. This information is not correct for all but one of the regional networks. One has to know the network id to get the correct network information table.
There is only one simple solution for these problems: Talk to your cable provider they need fix it!
How can we fix it ?
See both the (workaround) patch provided by Janne and the script at the ticket #7486 for this issue.
modified mythic.pl solution
1. Install MythTV as usual
$ apt-get install mythtv
2. Create a czap channels.conf
Warning: This will take several hours!
At least on my machine running this combination of (dvb)scan, w_scan and different parameters finds more channels than a simple scan.
3. Import into MythTV
Import czap-final.txt (created in step 2) into MythTV.
4. Fix database with modified mythic.pl
This script will fix the database and enable EIT on all channels. Its a modified version of mythic.pl, because channel names dont match exactly depending on the different scanners.
$ /etc/init.d/mythbackend stop
$ mythic-ignore_channel_name.pl myusername mypassword ./czap-final.txt
$ /etc/init.d/mythbackend start
Ziggo (merger of @home, Casema and multikabel)
No intention of changing this. All their supported boxes have the possibility to enter the frequency and network number. This non-DVB behaviour seems to become more and more standard.
Ziggo Netherlands Problem Fix (you'll have to compile from source though)
A fix for this problem in MythTV is available. See #7486 for details.
For master and fixes/0.25 a pullrequest has been sent to the mythtv devs. The latest discussion with the MythTV dev's (5/dec/2012) shows that this fix could create problems elswhere.
So it will probably not be merged in it's present state.
However, it works quite well with Ziggo Netherlands, so until an even better fix becomes available, this one will be around.
The patch also works with fixes/0.26
If you are compiling from source, aplying this fix is very easy:
(Lines 3 and 4 of the following commands do the trick)
git clone https://github.com/MythTV/mythtv.git && cd mythtv git checkout fixes/0.25 (or fixes/0.26) git remote add -f bas-t git://github.com/bas-t/mythtv.git git cherry-pick d0e53a851e ## this is Klaas de Waal's latest unmodified patch cd mythtv ./configure --whatever-you --need make make install
Now you can manualy set the Network ID you need at the bottom of the section "Video Sources". (for me that would be 9700)
After that, you can scan in the section "Channel Editor -> Zender Scan"
Just provide the values you got from ziggo, so in my case (ziggo groningen) frequentie= 369000000, Symboolsnelheid = 6875000, Modulatie = QAM 64
These are the exact same values you need to setup your ziggo tuner. So if you subscribed to a ziggo dvb service, you have these values.
Remember to untic "Enkel onversleuteld" before scanning.
The 4 regional channels where in my case not detected properly, but all the other channels where fine, including radio channels.
Germany has some major providers and several small/regional providers (around 50% of population is forced to use the smaller broken ones).
Resells to: Kabel Medien Service Muenchen, ...
State: 2008-06-26 Broken The modified mythic solution worked for me!
Technical support told me that they copy the NIT directly from SAT, because the don't know any receiver which has problems with this. They WON'T fix it.
I had the problem that EIT did not show (watching TV was no problem). Reason: MythTV could not detect NID and TID and left the columns transportid and networkid of dtv_multiplex NULL. Filled them manually with the respective values from ASTRA. Also filled all cells with NULL values in this table. After restart of mythbackend, eit tuned channels appeard immediatelly.
Funk & Technik (http://www.kabel-net.de/) and AVC (http://www.avc-online.de)
~ 50% of the cable network from Cottbus/Germany
State: 2008-06-26 Broken
NIT/NIT-o directly from Astra 19.2E and They WON'T fix it.
Skanderborg AF gets the DVB stream directly from YouSee - and broadcast that to the costumers.
They do not modify NIT - resulting in a wrong network ID being broadcasted.
I've tried both the dvb_broken_nit_providers1.diff and dvbstreamdata.cpp.patch. Both patches seems to get a pretty good scanning (Though NOT all channels are found).
UPDATE: 31/05-09: Lately things has changes on the YouSee network - and the dvb_broken_nit_providers1.diff patch seems to no longer do the trick!
The dvbstreamdata.cpp.patch patch seems to work fine though!
The "mythic.pl solution" gets a good amount of channels (The same as with above patches) - but still a few channels are missing.