Issues with QAM256, DVB-C

Added by Arjan Groeneveld about 12 years ago

Hiya,

I have been using this excellent piece of software for a couple of weeks now and it's doing exactly what I want it to do.
However, I have noticed an issue that involves all frequencies using QAM256. It throws out errors about 'Transport stream errors' and Continuity errors'.
That wouldn't be such a problem, weren't it not for pausing video/audio and artifacts. Anyone out there that has encountered these problems and knows how to fix them? I already cancelled out the signal quality, changed cables and DVB-C cards, but the problem remains.

I'm running Ubuntu 12.04, Technotrend CableStar HD2 DVB-C (Ziggo Digital Cable subscription) and the latest tvheadend from git.

Multimedia controller: Twinhan Technology Co. Ltd Mantis DTV PCI Bridge Controller [Ver 1.0] (rev 01)
 Subsystem: Device 1ae4:0002
 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
 Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- &lt;TAbort+ &lt;MAbort- &gt;SERR- &lt;PERR- INTx-
 Latency: 32 (2000ns min, 63750ns max)
 Interrupt: pin A routed to IRQ 17
 Region 0: Memory at f0000000 (32-bit, prefetchable) [size=4K]
 Kernel driver in use: Mantis
 Kernel modules: mantis

I figured it might be driver related, so I tried updating that as well, but that hasn't really made any difference. All other channels on QAM64 are perfectly fine, it only affects the channels on the QAM256 frequencies.

Replies (5)

RE: Issues with QAM256, DVB-C - Added by Arjan Groeneveld about 12 years ago

Really, nobody with any ideas regarding this issue...¿ Could it be tvheadend related¿ Automatic scan did not return any of the QAM256 transponders, I had to add them manually.

RE: Issues with QAM256, DVB-C - Added by Arjan Groeneveld almost 12 years ago

Seeing as my provider is changing more and more transponders into QAM256 streams, this is becoming more of a problem. Soon I won't be able to watch any channel anymore. Please, somebody give some suggestions and/or pointers. Getting desperate here.

Thanks in advance...

RE: Issues with QAM256, DVB-C - Added by domax X almost 12 years ago

I'm experiencing the same issue, a lot of channels are missing so this is a big problem for me also. Anyone have a clue on getting this solved?

RE: Issues with QAM256, DVB-C - Added by zwaz zwaz almost 12 years ago

i had the same issue with mij HDHomerun. Every QAM 256 doesn't work any more. The quality is going to zero and can not scan to the channels.

RE: Issues with QAM256, DVB-C - Added by domax X almost 12 years ago

Hey zwaz zwaz,

Eventually i found out that it was my fault. I followed some guides on the Internet, but none of them mentioned the initial setup tasks for the hdhomerun devices itself.

The DVB-C modulations need to be set in order for the HDHomeRun device to correctly find channels in the scan - see http://www.silicondust.com/support/hdhomerun/instructions/dvb-c/.

So i set the following with the Windows HDHomeRun Setup tool, (this can be done also with hdhomerun_config):
Country, and Zipcode
Tuners: Digital Cable
and most important:
DVB-C: Selected modulation types:
- qam64 Symbolrate 6875
- qam 256 Symbolrate 6875

After setting these, tvheadend found the qam256 channels.
Strange was that still some were missing on the scan on my first 3 tuners, the 4th found all. I was missing Nederland 3 HD for example. Only the 4th tuner found it. Then i just mapped these on the other 3 tuners, and the worked without a problem on the first 3 tuners.
Now everything works.

Hope this helps you

Donald

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