Maybe better to look at a layer closer to the python. See:
http://code.google.com/p/kamaelia/source/browse/trunk/Code/Python/Bindings/python-dvb3/dvb3/frontend.pyx#126
Teh QPSKParameters class is filled from the 'frequency' parameter and the
'feparams' you provide. You therefore need to specify:
inversion
symbol_rate
fec_inner
in the feparams dict you are creating.
Ignore my earlier mesasge where I incorrectly assumed you were trying to
tune to the BBC freesat service! Use the symbol rate and frequency that
you have been using. Hein suggests the FEC you need is 3/4. You can
probably set inversion to auto - or at worst just try all three options.
The old code Michael attached to an earlier email seems to indicate that
to set the polarisation, other stuff needs doing - to do with SEC voltages
(I've no idea what they are). You could try taking you own copy of the
DVB_Multiplex.py and adding the code to set the polarisation?
Matt
On Fri, 20 Nov 2009 10:00:24 -0000, luca72 <[email protected]> wrote:
> Thanks
> I try to explain what i need to do using python.
>
> The base data are:
> DVB-S
> Frequency 11977
> pid 1296 Sky Italy ECM pid
> Polarization Horizontal
> symbol rate 27500
>
> If i understand right at first i have to setup the front end is it
> correct?
> Locking dvb-3 api for dvb-s frontend i have the follow params:
>
> struct dvb_frontend_parameters {
> uint32_t frequency; /* (absolute) frequency in Hz for
> QAM/OFDM */
> /* intermediate frequency in kHz for
> QPSK */
> fe_spectral_inversion_t inversion;
> union {
> struct dvb_qpsk_parameters qpsk;
> struct dvb_qam_parameters qam;
> struct dvb_ofdm_parameters ofdm;
> } u;
> };
>
>
> For satellite QPSK frontends you have to use the QPSKParameters member
> defined by
>
> struct dvb_qpsk_parameters {
> uint32_t symbol_rate; /* symbol rate in Symbols per
> second */
> fe_code_rate_t fec_inner; /* forward error correction (see
> above) */
> };
>
> freq = 119.770000
> feparams = {"symbol_rate" : 27500,
> }
>
> I stop just here i heve made no more code because i have the error,
> so i don't continue.
>
> Now my idea is ,today when i'm at home i write this small script and i
> see the output and the i post here so we can have a new idea.
>
>
> #include <linux/dvb/frontend.h>
>
> struct dvb_frontend_info info;
> int fd;
>
> if ((fd = open ("/dev/dvb/adapter0/frontend0", O_RDWR)) < 0) {
> perror ("open failed");
> return -1;
> }
>
> ioctl (fd, FE_GET_INFO, &info);
>
> Regards
>
> Luca
>
>
>
> On 20 Nov, 10:36, Michael Sparks <[email protected]> wrote:
>> Hi Luca,
>>
>> On Friday 20 November 2009 07:39:12 luca72 wrote:
>>
>> > now i can't test it
>>
>> > Many thanks i will inform you.
>> > PS:I think that i'm your nightmare (sorry)
>>
>> No, not nightmare. Someone testing current code in a scenario we
>> haven't tried
>> since that code was written is actually a dream scenario. What is
>> making it
>> hard to help is not posting a copy of the actual code you're running.
>>
>> Fragments are good, and you have the context of the fragments, so they
>> make
>> sense to you. However, simply posting this by itself...
>>
>> from Kamaelia.Device.DVB.Core import DVB_Multiplex
>> from Kamaelia.Chassis.Pipeline import Pipeline
>> from Kamaelia.File.Writing import SimpleFileWriter
>>
>> import dvb3
>>
>> freq = 119.770000
>> feparams = {"symbol_rate" : 27500,
>> }
>>
>> (for example - some your mail at 13:41:15 -0800 (PST) )
>>
>> ... doesn't give me the full picture.
>>
>> When you then post this:
>> and i get the following error
>>
>> The file frontend.pyx could not be opened.
>> ...
>> and after i gat :
>> The debugged program raised the exception unhandled IOError
>> "(22, 'Invalid argument')"
>> File: frontend.pyx, Line: 364
>>
>> These two errors look contradictory, which is confusing.
>>
>> I'm explaining this because taking the time to report what you're
>> trying, and
>> the results you're seeing is fantastic feedback, and I suspect looking
>> at the
>> original early code that we may need to change some code with regard to
>> configuring the front end, but until I see the full file you're
>> *currently*
>> editting and the *current* sourcefile, I have no chance of
>> reconstructing
>> exactly what's happening.
>>
>> In order to allow me to help you, I simply need that information.
>>
>> Once again, regarding this:
>>
>> > PS:I think that i'm your nightmare (sorry)
>>
>> Please let me put your mind at rest - someone (anyone) taking the time
>> to
>> report back and try using code that hasn't been tested in the scenario
>> you're
>> using it, is not a nightmare, it's closer to a dream scenario - since
>> it's
>> useful feedback.
>>
>> At present I think, that the current code is not configuring the
>> satellite
>> frontend before passing in the fe.params. It looks like with DVB-T & -C
>> you
>> can more or less "just use it", whereas with DVB-S the setting of
>> horizontal
>> matters. This quite possibly requires a change to our code as well as
>> yours,
>> hence me asking for information which you may feel repetitious, however
>> what
>> I'm simply doing is trying to see precisely what's changing in the
>> system as
>> a whole :-)
>>
>> Thanks for persevering! :-)
>>
>> Regards,
>>
>> Michael.
>> --http://yeoldeclue.com/bloghttp://twitter.com/kamaelianhttp://www.kamaelia.org/Home
>
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--
| Matt Hammond
| Research Engineer, FM&T, BBC, Kingswood Warren, Tadworth, Surrey, UK
| http://www.bbc.co.uk/rd/
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