[mythtv-users] Multi-standard DVB frontend support?

[Niklas Brunlid]

On 1 May 2012 12:18, Mike Perkins <mikep at randomtraveller.org.uk> wrote:

> On 30/04/12 22:10, Niklas Brunlid wrote:
>
>> One week with no replies, figured I'd bump this at least once. :)
>> On 23 April 2012 10:01, Niklas Brunlid<prefect47 at gmail.com>  wrote:
>>
>>>
>>> Apologies for cross-posting to the dev list, but it seemed appropriate.
>>>
>>> I'm wondering if there are any plans for support of multi-standard
>>> frontends? I came across
>>> http://article.gmane.org/**gmane.linux.drivers.video-**
>>> input-infrastructure/45723/**match=290ewhen<http://article.gmane.org/gmane.linux.drivers.video-input-infrastructure/45723/match=290ewhen>
>>> looking for clues as to why my PCTV 290e stopped working when I upgraded
>>> my
>>> Fedora 15 (now 16) combined backend/frontend server to a 3.x kernel and
>>> it
>>> mentions that it was introduced in Linux DVB API v5.4 or something.
>>>
>>>
>>  I think you'll have to explain in a little more detail exactly what your
> problem is, if you want someone to look at it. I run a back end with
> 2xDVB-T cards and a PCTV-290e USB dongle for HD and I have no problems at
> all. I'm running a Debian 3.0.x kernel on that box.
>
> Where exactly does your front end enter into this? Tuners are in back
> end(s). If you mean you have a problem displaying SD/HD content, that's got
> nothing to do with your tuners.
>

My mail was basically a shot in the dark since my 290e doesn't work since
the upgrade. Sorry for the confusion - I don't mean frontend as in the
MythTV frontend, but as the device in /dev/dvb/adapterN/*frontend*N.

As I understand it, in the new Linux DVB API, the
/dev/dvb/adapterN/frontend is no longer split into frontend0 and frontend1
if your device is multi-standard. The 290e supports DVB-T2 and DVB-C on the
same input but has to be told which one to use, and earlier this was solved
by having device 0 represent DVB-T2 and device 1 represent DVB-C. Although
you had to trick it by symlinking all the other devices - demux0, dvr0 and
net0 - to demux1, dvr1 and net1, since only frontend1 was created.

In the new API the application has to know about the change, and explicitly
tell the device to switch between the standards. From my limited
understanding it might be something like
http://www.linuxtv.org/wiki/index.php/S2API that has to be used?

Since this change, my box can no longer use the 290e DVB-C for input. Maybe
it works on your system because you use DVB-T2?

BTW, I also found some discussions specifically about the 290e here:
http://www.mail-archive.com/linux-media@vger.kernel.org/msg31845.html

I did get dvbscan or w_scan or something to work against
/usr/share/dvb/DVB-C/se-comhem last week, although it seems to use DVB-C2.
w_scan claims support for Linux DVB API 5.3 and says that the device is
buggy:


$ w_scan -A2 -fc -cSE -G -X |tee .czap/channels.conf
w_scan version 20120112 (compiled for DVB API 5.3)
using settings for SWEDEN
DVB cable
DVB-C
scan type CABLE, channellist 7
output format czap/tzap/szap/xine
WARNING: could not guess your codepage. Falling back to 'UTF-8'
output charset 'UTF-8', use -C <charset> to override
Info: using DVB adapter auto detection.
        /dev/dvb/adapter0/frontend0 -> CABLE "Sony CXD2820R": very good :-))

Using CABLE frontend (adapter /dev/dvb/adapter0/frontend0)
-_-_-_-_ Getting frontend capabilities-_-_-_-_
Using DVB API 5.5
frontend 'Sony CXD2820R' supports
DVB-C2
INVERSION_AUTO
QAM_AUTO
FEC_AUTO
FREQ (45.00MHz ... 864.00MHz)
This dvb driver is *buggy*: the symbol rate limits are undefined - please
report to linuxtv.org
-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
73000: sr6900 (time: 00:00) sr6875 (time: 00:05)



/ Niklas
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