[linux-dvb] scan command returning wrong FEC ?

Simon G linuxtv at simong.net
Mon Dec 17 08:51:32 CET 2007


When using the scan command to create a channels.conf I get locks on all
my wanted channels, but the returned channels.conf appears to have
incorrect FEC low and high.

It returns ...

FEC_3_4:FEC_1_2:QAM_64

instead of the correct ?

FEC_2_3:FEC_1_2:QAM_64

I say correct because I only get a lock and can watch TV with my "correct"
channels.conf

Investigating further with dvbsnoop on PID 0x10 (NIT) ...
ie. dvbsnoop 0x10;  dvbsnoop -crc 16

DVB-DescriptorTag: 90 (0x5a)  [= terrestrial_delivery_system_descriptor]
            descriptor_length: 11 (0x0b)
            Center frequency: 0x04047140 (= 674000.000 kHz)
            Bandwidth: 0 (0x00)  [= 8 MHz]
            priority: 1 (0x01)  [= HP (high priority) or Non-hierarch.]
Time_Slicing_indicator: 1 (0x01)  [= Time Slicing is not
used.)] MPE-FEC_indicator: 1 (0x01)  [= MPE-FEC is not used.)]
reserved_1: 3 (0x03)
            Constellation: 2 (0x02)  [= 64-QAM]
            Hierarchy information: 0 (0x00)  [= non-hierarchical (native
interleaver)]
            Code_rate_HP_stream: 2 (0x02)  [= 3/4]
            Code_rate_LP_stream: 0 (0x00)  [= 1/2]
            Guard_interval: 3 (0x03)  [= 1/4]
            Transmission_mode: 1 (0x01)  [= 8k mode]
            Other_frequency_flag: 1 (0x01)
            reserved_2: 4294967295 (0xffffffff)

Note, it also says 3/4 1/2 instead of 2/3 1/2 ??

Is this a fault of the transmitter set-up here in Sweden ?


/Simon.





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