[linux-dvb] scan command returning wrong FEC ?

Robert Schlabbach robert_s at gmx.net
Mon Dec 17 14:55:17 CET 2007


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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