Tvheadend

Hi there

I recently decided to give TVHeadend a shot, after many years using MythTV. I've been using sasc-ng (it reports SC version 1.0.0pre-HG-61975953edd0+ at startup) with my danish (StofaXtra / Zaptor) Irdeto 2 card for quite a while now, and haven't had many issues.

I have discovered that I am unable to perform a channel scan using TVHeadend through the virtual (dvbloopback) adapters. The scan works blazingly fast, however, if I scan through the physical adapters. Oddly enough, the 'scan' app from the linuxtv guys (which is arguably our reference implementation) works just fine.

Unfortunately I have relatively little debug information to offer at present - I'd be happy to provide it if somebody can tell me what I need to provide. What I can see is that when I manually add the initial scan multiplex to the physical adapter, it scans and finds all the other muxes, and proceeds to scan and register services. When I do the same to the loopback adapter, the mux doesn't get scanned - "Muxes awaiting initial scan:" starts at, and remains at 1. Debug logging shows nothing.

I have also looked at the files TVHeadend generates - when using the physical adapter, the following file is generated for the initial scan mux:

{
        "quality": 100,
        "enabled": 1,
        "status": "OK",
        "transportstreamid": 1,
        "network": "Stofa Aarhus",
        "frequency": 346000000,
        "symbol_rate": 6900000,
        "fec": "3/5",
        "constellation": "QAM64" 
}

While the same details added to the virtual adapter yields the following:

{
        "quality": 100,
        "enabled": 1,
        "status": "OK",
        "transportstreamid": 65535,
        "frequency": 346000000,
        "symbol_rate": 6900000,
        "fec": "NONE",
        "constellation": "QAM64" 
}

So there's a difference between the detected TSID's... And the fec value remains at 'NONE' (I actually input the value as none for both adapter types - it changes to 3/5 automatically when TVHeadend does it's thing with the physical adapter). I've tried altering these values in the relevant file and restarting, but the program doesn't react to the change. It also does not change the values back. I'm frankly not sure what to make of that.

Does anybody else have experience with this combination? If you got it working, did you have to do anything special with your config for channel scanning to start working?

(I'm aware this might be considered a 'descrambling' issue, but I put my question here since, in the context of TVHeadend, we're not trying to descramble, only tune.)

Cheers,

/drdaz