Use with mythbuntu

[davtom]

Hi,

I just want to establish what it is necessary to do to get this card working with Mythbuntu. I am currently using 11.04. I know 11.10 is about to be released but Beta 2 fails to install on my system at present.

It seems to be the case that the driver is already in the kernel, but the firmware to be uploaded to the card is not included in Mythbuntu as standard. I did get this card working for DVB-S, but not DVB-S2, by installing the driver in the downloads available from here. (I think it would pick up the DVB-S2 channels but switching to them did not work.)

If you want to do it in an easier way, am I right in thinking it is possible to install the linux-firmware-nonfree package by doing:

sudo apt-get install linux-firmware-nonfree

Is it the case that this should work with both DVB-S and DVB-S2, or are there specific versions of firmware that are needed to use DVB-S2?

Many thanks.

[davtom]

Ok, latest info...

I installed Mythbuntu 11.10 on my box last night. The TBS 8920 will not work out of the box with this system; work is needed.

This isn't gonna be a complete HOWTO for it, but I will explain the steps I went through that are extra to the normal requirements for setting up a combined frontend/backend system.

I downloaded the latest driver from this site which is linux-tbs-sources_111013.zip at the time of writing. I copied the card firmware into the appropriate place and built the driver as specified in the README file for Ubuntu. I did the make install and reboot.

I built szap-s2, but I didn't use it. I couldn't build scan-s2 because it complains that the DVB-S2 API is the wrong version (it is expecting 5.1). I didn't try to fix that.

The other unusual thing you have to do is in the MythTV backend configuration. There are two default timeouts for something like signal lock and tuning. These are shown as 7000ms and 10000ms. I saw on a site somewhere that somebody changed these to 60000 and 62500ms respectively, so I did that myself. After doing that, scanning works OK for DVB-S.

To get the scan started for DVB-S, I used the following parameters for Astra 28.2E:

Signal types: TV/Radio
Freq: 10714000 (kHz)
Polarity: Horizontal
Symbol rate: 22000000
Mod Sys: DVB-S
FEC: 5/6
Modulation: QPSK
Inversion: Auto
Rolloff: 0.35

I went into the frontend and channel hopping was working no problem.

I haven't yet got DVB-S2 to work. During scanning, it locks on to the frequency and shows a signal, but shows no signal quality. These are the parameters I've seen which I think corresponds to BBC HD and BBC 1 HD at the time of writing on Astra 28.2E:

Signal types: TV/Radio
Freq: 10847000
Polarity: Vertical
Symbol rate: 23000000 (this is not an auto-completed item! Several sites confirm that this should be 23000000 and not 22000000.)
Mod Sys: DVB-S2
FEC: 8/9
Modulation: QPSK
Inversion: Auto
Rolloff: I have tried 0.20, 0.30 and 0.35

I'm still not sure of what's going on there. I can pick up HD signals that are broadcast using DVB-S rather than DVB-S2 without any problem. If anybody can offer help with this, that would be great.

I wonder if the problem could be the time of day that I was trying this. I've got a set top box that I had problems tuning into this channel with, and to get it working, in the end I had simply to do it at a different time of day when the channels were broadcasting.

My main reason for posting this is maybe it will help others that have trouble with this card. It looks like the level of support offered here by TBS is good, and the cards are competitively priced.

[davtom]

More info: It is possible to build (with make) and copy to /usr/local/bin (with make install) scan-s2 on a Mythbuntu 11.10 system by patching scan.c as follows:

Code: Select All Code

#include "atsc_psip_section.h"

#if DVB_API_VERSION != 5 || DVB_API_VERSION_MINOR != 1
#error scan-s2 requires Linux DVB driver API version 5.1!
#endif

#define CRC_LEN      4

On the line between #include and #if, add:

Code: Select All Code

/*

On the line between #endif and #define, add:

Code: Select All Code

*/

This turns off the check for the DVB API version. I suspect that Mythbuntu 11.10 has a DVB API later than 5.1.

[davtom]

Ok... Latest info:

I installed kaffeine with:

sudo apt-get install kaffeine

I got it to scan the available channels on the TBS 8920. That went fine; especially as I was able to just tell it to scan Astra 28.2E - and it even picked up BBC HD and BBC 1 HD, which are broadcast using DVB-S2.

To get it to show the channels, I had to also do the following:

sudo apt-get install libxine1-ffmpeg

This all works fine. My system is underpowered for playing dvb-s2 at present (I need to buy an nvidia video card to offload the dvb-s2 processing) but kaffeine does manage to show a picture that updates at about 50% of the rate it should, so the signal is obviously getting through.

I'm posting this partly because it may help others, and partly because it may help me when I forget all this in the future, and need to come back to it.