Some people call me Fredrik

I just upgraded my HTPC from some old Ubuntu to Debian Lenny, mostly to get the newest 0.22 version of MythTV. The installation was pretty straightforward except that the channel scanning didn’t work. For this I had to use the scan program to get a channels.conf file to import into MythTV. After that all was fine. Except that I didn’t have any EIT data. And that annoying problem has now been bugging me for over two weeks and hundreds of browsed MythTV forum pages and HOWTOs. Until I today found a solution.

All user forums and help pages and HOWTOs suggested that the information in channels.conf isn’t sufficient, and that’s why a channel scan based on that information fails to get EIT data. Everyone suggested to delete all channels and do a “Full Scan”. Problem is that there are two different Full Scans in mythtv-setup: Full Scan of Existing Transports and Full Scan (Tuned). I always went for the Full Scan of Existing Transports since the Tuned Full Scan needed parameters that I didn’t have nor knew how to acquire (although I did desperately try it once with some frequencies from the transports list and other settings set to Auto, but to no avail).

Over and over again, I deleted channels and rescanned. With different EIT data configurations and onairguide settings and what not, I tried to get some program information. I even manually modified some networkid settings in the database. But nothing. Not until I for the n:th time turned to Google for some answers and stumbled upon a forum thread that gave me some parameters for the Full Scan (Tuned). I tried these out and Presto! the mythbackend.log started singing like an angel choir. EIT data was finally added!

So what are these mysterious parameters that I found? They are:

Frequency: 162000000
Modulation: QAM_64

These are most likely specific to the Welho network in Helsinki region, and I don’t really know for a fact where they come from. However, when investigating my old channels.conf file, I found that these parameters were present for some of the channels I had been using, but other channels had other settings, both for frequency and modulation. Here’s an example:

DINA:162000000:INVERSION_AUTO:6900000:FEC_NONE:QAM_64:641:642:64000

So what still puzzles me is how MythTV was able to find the same channels using the channels.conf file and the Tuned Full Scan with the above (seemingly insufficient) parameters. And perhaps the Tuned Full Scan would have yielded the same result with some other frequency and modulation combo from the channels.conf file? I don’t know and I won’t put any more effort into this matter right now. Too much sleep has already been lost.