Is Tvheadend able to receive DVB-S2X signals with a FEC of 25/36?

downbythestream

A major USA television network is now transmitting using DVB-S2X on C-Band, and a weird FEC of 25/36. Neither of those show up in the MUX creation dropdowns in Tvheadend. I would just like to know, is Tvheadend capable of receiving these signals assuming it is connected to a satellite tuner card that has that capability, or does it simply not support those formats?

DeltaMikeCharlie

The best that I can suggest is trying "AUTO" and see what happens.

Maybe you could look for a DVB scan file that contains the updated information.

Maybe you could build a custom mux scan file that contains the values that you need.

<installation location>/dvb-scan/dvb-s

DeltaMikeCharlie

I hacked a DVB scan file just to see what happened.

I can't say that any of the other parameters are correct, but it recognised the correct FEC.

My hacked file looked like this:

[CHANNEL]
        DELIVERY_SYSTEM = DVBS
        FREQUENCY = 11720000
        POLARIZATION = VERTICAL
        SYMBOL_RATE = 27692000
        INNER_FEC = 25/36
        INVERSION = AUTO

downbythestream

DeltaMikeCharlie Well the issue is not so much the setting of the FEC (though I am not sure if changing it manually actually works, or if Tvheadend just considers that an invalid value). I found that you can manually enter a FEC in the web interface, you just have to choose an existing setting and then put your cursor at the end of the field and backspace and enter the value you need. What more concerns me is that Tvheadend doesn't seem to be aware of DVB-S2X as a valid format.

downbythestream

DeltaMikeCharlie downbythestream Since it appears you can't edit a previous post I will just add this: Take a look at this TBS card's specifications:

https://www.tbsdtv.com/products/tbs5520se_multi-standard_tv_tuner_usb_box.html

You will see that not only does it support DVB-S2X but also a bunch of weird FEC's, under DVB-S2X it shows these:

DVB-S2X

      QPSK:   13/45, 9/20, 11/20

2_4_2_APSK:   100/180, 104/180

      8PSK:   23/36, 25/36, 13/18

8_8_APSK: 90/180, 96/180, 100/180, 18/30, 20/30

16APSK: 26/45, 3/5, 28/45, 23/36, 25/36, 13/18, 140/180, 154/180

4_12_16rb_APSK: 2/3

4_8_4_16_APSK: 128/180, 132/180, 140/180

Note that 25/36 is supported for both 8PSK and 16APSK. But my point is that if only the FEC's given in the dropdown work, or if Tvheadend has no awareness of DVB-S2X then this device might not be compatible, which would be a real shame since Tvheadend has handled every other device I have tried with it including other TBS satellite tuner cards. Note I do not currently have one of these devices, I am trying to find out if there's any chance it will actually work with Tvheadend before possibly making a purchase.

Flole

There is currently (since quite some time to be fair) an ongoing effort to get test hardware for several features. It might make sense to add a DVB-S2X card to that list. I don't think adding support would be too complicated. If there is a broadcast which I can receive from Germany I might be able to look into it (not with a TBS card though, I prefer USB tuners and TBS is known for various driver shenanigans).

Ron L

SYS_DVBS2 is used for both DVB-S2 and DVB-S2X as S2X is just an extension of S2 according to the API docs. All the additional S2X FECs and Modulations appear to be added into frontend.h so if you have recompiled TVHeadend recently with a kernel that has drivers for your DVB-S2X capable device that should all be in there. The only issue I can foresee might be if your device driver requires FEC to be manually specified before a lock can be obtained and TVHeadend can't send the required FEC. Seems an unlikely scenario as drivers generally find FEC automatically on their own.

Any way, as I read the TVHeadend source code linuxdvb_frontend.c The S2X FECs and Modulations are listed there now so someone has brought it up to date already.

I don't own an S2X card as yet and am debating whether it's worth the purchase or not. Other than TBS I'm not sure who makes them. I have one TBS DVB-S2 USB device at present and so far it's been excellent other than the kernel maintainers not including the drivers in mainline.

Flole

Apparently Sundtek produces such cards. However, it seems (based on another thread in this forum) that they suggest using modified versions of Tvheadend, which might cause other issues and is not recommended.

Jonas Lang

With the slow demise of satellite as domestic delivery system for TV I wouldn’t bother with those expensive and poorly supported driver and firmware wise PCIe and USB tuners. A simple option like a Sat/IP tuner would be the obvious choice. No firmware updates or broken drivers to worry about either.

Flole

They still need to support DVB-S2X, I'm not sure if they usually do.

Also Tvheadend should support it for USB tuners, just in case someone wants to use it.

Ron L

The channel in question is on C Band and would likely be on a dish that requires control of a linear actuator for dish rotation. Your Sat/IP tuners won't handle any of those things. In North America they are essentially completely useless.

Jonas Lang

Ron L if you are using C band in NA you’re likely to have something like a vbox
https://www.orbitadigital.com/en/satellite-terrestrial/antennas/motos/27787-vbox-iii-positioner-for-all-types-of-actuators-supports-diseqc.html and your Sat/IP tuner fits in nicely with that setup.

Again issues with firmware/drivers is the last thing users want to contend with when setting up their HTPC and the majority of issues on this forum relate directly to this very subject.

Ron L

Well post some links to Sat>IP equipment that can support 5150 C Band and 10750 Ku Band LNBs and can deal with channels spread over 20 or 30 different satellites using a dish that rotates as well as integrate 5G wave guide frequency filters.