dvbbasebin questions

Alberto Milla amilla at vicomtech.org
Wed Mar 16 15:40:39 PDT 2011

I'm afraid that I can't give you a good answer, because my experience
with gstreamer and DVB-T are quite short. Then be careful.

When you say "dvbsrc does all the low-level parsing itself". I
disagree IMHO, the EIT parsing is done in mpegtsparse

- http://cgit.freedesktop.org/gstreamer/gst-plugins-bad/tree/gst/mpegdemux/mpegtsparse.c?id=RELEASE-0.10.21

If you look at "mpegts_parse_handle_psi" function, there classifies
the type of table that has arrived. If Freeview is not DVB-T compliant
I think that is there where you will have to modify the code. In the
case of Freesat I can't give you any answer because I have only worked
with the terrestrial standard.

Continuing with the program recording and the EPG data extraction. In
France for example, they send all the channels' schedule by all the
multiplex, however in Spain the only send the schedule of the channels
that form the multiplex at you are listen to. Reading you question It
looks like the UK system is like the spanish. I think the solution is
in the tuner, if you use a simple tuner you can't get two dvbsrc, but
if you have a dual digital tuner it must be possible.

On 16 March 2011 15:09, Tony Houghton <h at realh.co.uk> wrote:
> On Wed, 16 Mar 2011 00:13:31 +0000
> Tony Houghton <h at realh.co.uk> wrote:
>> I wrote a small test program in python, based on what I learnt from
>> the dvbscan.c code; I've attached it. The mpegtsparse element doesn't
>> seem to be working at all; the only ELEMENT messages I'm getting are
>> dvb-adapter and dvb-frontend-stats which I think come from dvbsrc, not
>> mpegtsparse. And mpegtsparse doesn't create any pads. If I don't
>> include the extra video/audio pids as well as the SI pids I get a
>> dvb-read-failure ELEMENT message.
> I spotted my own mistake, I only set the dvbsource to STATE_PLAYING
> instead of the pipeline. It's working now. I still get the
> dvb-read-failure messages if I only include SI pids but it seems
> harmless and I get the section messages OK.
> I'm still puzzled by the other two issues though:
>> Another oddity is that I originally used
>> set_properties("adapter", adapter, "frontend", frontend) instead of a
>> separate set_property for each property, but it didn't work. The
>> adapter number stayed 0 after I had set it to 1 (also if I reordered
>> the properties so adapter came after frontend).
>> Also, why is the "pids" property write-only? In a complex application
>> it would be nice to know what the pids already are to make sure
>> different functions don't conflict with each other.
> The most useful aspect of being able to read pids would be so that I
> could use a dvbbasebin to stream or record a programme and add EIT pids
> to its child dvbsrc to "harvest" the EPG at the same time.
> Or is it possible to use two dvbsrc elements on the same adapter and
> frontend simultaneously?
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