[linux-dvb] scan command returning wrong FEC ?

Simon G linuxtv at simong.net
Mon Dec 17 15:31:13 CET 2007


Regarding my TDA10046 .
That explains why I was able to get a LOCK with my Nova T 500 when I set
FEC_AUTO but not the Terratec !
I'll give it a try by commenting out the line in the source code.

Regarding the NIT info.
I suspected as much, lets see if I even get a reply to my request to fix it.
It must be just the Karlstad transmitter that has this problem as I see
other Swedish people on this list don't seem to have the same problem
running Linux.
Teracom were using 3/4 1/2 up until recently when they appear to have gone
over to 2/3 1/2.

Thanks for all help.

/Simon.


> From: "Simon G" <linuxtv at simong.net>
>> http://simong.net/dvb/new_test.ts
>> This appears to include PID 0x0015 as I can read it with dvbsnoop.
>
> Yep, it's a full TS now, but no PID 0x0015, because it's an MFN:
>
> terrestrial delivery system:
> frequency = 650000000 Hz, bandwidth = 8 MHz, HP stream, constellation =
> 64-QAM
> hierarchy = none, HP_code_rate = 3/4, LP_code_rate = 1/2
> guard_interval = 1/4, transmission_mode = 8k, other_frequency = YES
> Frequency list descriptor:
> Terrestrial frequency = 658000000 Hz
> Terrestrial frequency = 594000000 Hz
> Terrestrial frequency = 554000000 Hz
> Terrestrial frequency = 570000000 Hz
>
> You'd have to read the TPS information from the demodulator to see what
> the
> actual FEC is, but anyway:
>
> I looked at the source code:
>
> http://linuxtv.org/hg/v4l-dvb/file/266e6dd2dcb6/linux/drivers/media/dvb/fro
> ntends/tda1004x.c
>
> and found that in lines 708 through 711, Andrew chose to only enable
> automatic FEC detection on the TDA10045 - but your board has the TDA10046
> on it. To fix this, you could just remove the condition in line 710, i.e.
> change it from:
>
> if (state->demod_type == TDA1004X_DEMOD_TDA10045) {
>
> to
>
> {
>
> and rebuild. But you should also try to contact Teracom and tell them the
> DVB-T parameters they are transmitting in their NIT are not correct...
>
> Hope this helps,
> --
> Robert Schlabbach
> e-mail: robert_s at gmx.net
> Berlin, Germany
>
>
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