QAM Channel Headaches (nearing migrane)

[greggerm]

PROBABLE SOLUTION:

I did not "channel scan" both of my 2250's digital tuners, I only scanned one and unknowingly presumed this information would translate to the other as well. With only one tuner having channel FRQ data, the other was left to its own devices and went all over the map tuning channels.

I scanned both tuners on a whim, and after a channel remap, everything has remained stable and properly assigned through service restarts and server reboots. Thanks to Opus4/Andy for noticing my mention of the dual scans and indicating it was the likely cause.

(Longer term stability is being evaluated now - if no updates are made to this thread, consider the problem solved!)

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And now, the original problem...
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I recently reinstalled my HTPC to a WHS/Extender arrangement and with it I am having some QAM mapping headaches.

Tested on Sage 6.5.9 (production) and 6.5.12 (beta) for WHS
I have a HVR-2250 for digital and analog capture, and an old PVR-250 for analog.
(Tested with shipping/production drivers and recent beta drivers for the 2250)

I have some sort of Channel Setup vs. Program Guide discontinuity, but not in the traditional mapping problem sense. In the setup source/channel mappings area, here's what the channel scan came up with:

On the FIRST VIEWING after the channel scan in via the channel setup area, the channels look correct. The "watermark" labels for the channels make it apparent that I am viewing the proper programming for the expected channel, and I am a happy camper!

Logical ch 2-1 (physical 77-2-1) is WGBH. (Correct!)
Logical ch 36-1 (physical 77-36-1) is WSBE. (Correct!)
Logical ch 36-2 (physical 77-36-2) is WSBE-L. (Correct!)

I can view these channels in the setup area and validate that they are the correct broadcasts based on TV guide expectations, and both are given the green dot so I can get to them in the program guide. I'm not worried about EPG info yet, just that the right channels are visible in the right spots.

Alas, when I move to the program guide to view the channels, things don't stay the same.
Even though after the scan all looked good, when I view the channels via the program guide I get the following:

Sage channel 2-1 broadcasting WGBH (Correct and expected)
Sage channel 36-1 now broadcasting WGBH (Incorrect, should be WSBE)
Sage channel 36-2 now broadcasting WSBE (Incorrect, should be WSBE-L)
Can't find any broadcasts of WSBE-L

Now if I return to the channel setup area to confirm, the formerly correct tunings have been broken as well. The digital channels are all discombobulated and no longer pointing to the broadcast programs they were when I viewed them immediately after the channel scan. (I did this several times with full Sage reinstalls to make sure the issue was repeatable)

QAM mapping can get ultra-frustrating, but that is usually the case with EPG data. I have a decent handle on how I will manage the EPG side, but right now, I'm just seeking stability in what the channels are showing.

I know my cable company is feeding me the channels, but Sage (or my 2250) doesn't want to let me watch them outside of the initial channel scan! Help!

-Greg

[greggerm]

Post-Solution Edit: This post by me contains info that did not play into the solution for the problem. In fact, it is likely that my theories in this post are probably completely wrong. Alas, I'll leave it up here as hemicuda had a response below.

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Following up with more information:

I noticed a .FRQ file in my Sage directory I hadn't noticed before, so I popped it open in a text editor to see what treasures it may hold.

As you know from my post above, after leaving the scan and going into the program guide, things get weird. WGBH takes over for WSBE, and WSBE-L simply disappears. My theory is that the physical channel numbering is getting thrown off.

The FRQ table shows four numbers of interest...
Major, Minor, Prog and Phy.

SageTV seems to set up it's physical numbers PHY-MAJ-MIN. After a channel scan, Sage reports the physical QAM channels for various stations as follows:
77-36-1 = WSBE
77-36-2 = WSBE-L
77-2-1 = WGBH

But, when looked at in PHY-PROG format, we'd see...
77-1 = WGBH
77-3 = WSBE
77-4 = WSBE-L

I'm wagering that this is confusing Sage, and I'll need to remap the physical channels to the PHY-PROG channel numbering scheme. That is likely the actual physical channel setup, versus using the major and minor scheme that Sage has picked up along the way. My theory is as follows...

* Sage looks to 77-36-1 for WSBE, but since there is no physical 77-36 channel, it defaults to prog 1 (77-1)- which happens to be WGBH.

* Sage looks to 77-36-2 for WSBE-L, but since there is no physical 77-36 channel and it tried above, it defaults to the next available program, prog 3 (77-3) - which happens to be WSBE(no-L)!

* The lost channel of WSBE-L (77-4) never gets found after the scan because Sage doesn't have any other physical channel 77 stations to tune.

Work is calling, so I can't mess around too much more now, but I'm hoping I am on to something here.

-Greg

[hemicuda]

I'm seeing what appears to be the same thing after my last rescan. Glad I did it on my testbed instead of the server itself. What a mess. I'll try to get time to look things over this evening and see if I can confirm your findings.

Still using the physical channel remap method on my server, i.e. the CH# at the start of each line in the .frq file.

Edit: I believe you are correct. There's a translation error between the .frq file and the mapping in Channel Setup.

[greggerm]

(No text)

[greggerm]

Ok - after a rescan and remap, the channels stuck around until I powered down the server to put it in it's proper home... the closet! Upon restart, the channels were all messed up again. PBS on NBC channels, CBS on ABC & FOX channels... etc.

After some choice language, I rescanned again over a small glass of J.D. Single Barrel.

This time, I performed the scan on BOTH digital tuners embedded in the 2250. This generated two FRQ files. Previously, I only had one. I have no idea if this will do anything for me, but we'll see.

I have remapped the channels, and the stations have remained stable for an hour or so. I've tested in the channel setup area, in the program guide, on my desktop computer client and on my extender. All is well so far.

Continued thoughts and theories by any of the readers is welcome...
-Greg

[Opus4]

If you've been scanning on only a single digital tuner, then that could explain a lot. If the 2nd digital tuner needed tuning info & you didn't scan using that digital tuner or didn't copy the scn/frq files correctly, it would have either no tuning info or the old tuning info that hadn't yet been updated.

Unless you know how to copy & rename existing scn and/or frq files, you have to do a scan with each digital tuner.

- Andy

[greggerm]

Service stop/start, and restart - channels stayed put.
Server reboot - channels were fine.
Overnight - remains to be seen, but confidence is much higher now.

I don't recall doing the scan on both tuners when I originally installed my system, but I guess I must have. It won't be something I forget anytime soon though.

The problem now makes sense, too - when I was testing the channel scan right in that screen, I was operating on the tuner that had just been scanned. When I exited that screen to test via the program guide, it is possible/likely that I was using the other tuner which didn't have any scan info, and it would be all messed up.

Andy, thanks for the reassurance on the problem. It seemed mighty strange that such a problem would crop up like it did, so I was starting to chalk it up to something that I as a network admin know all too well... operator error.

Again, thanks.
-Greg