[mythtv-users] DVB-S recordings from wrong channels

Thu May 26 13:09:37 UTC 2011

I'm having a problem with MythTV frequently recording the wrong channel. 
The programme guide shows the programme listed against the correct channel 
and once the programme is recorded it is shown as having been recorded 
from the right channel.  But the audio/video stream itself is coming from 
a different channel.

The logs don't seem to show why this is happening, although they do show 
very clearly that it is.  Maybe the programme recorder racing against the 
EIT scanner or something?  (Further comments below the log snippet)

2011-05-26 12:47:23.448 TVRec(7): ASK_RECORDING 7 0 0 0
2011-05-26 12:47:23.837 TVRec(9): ASK_RECORDING 9 0 0 0
2011-05-26 12:47:23.838 TVRec(10): ASK_RECORDING 10 0 0 0
2011-05-26 12:47:24.023 TVRec(8): ASK_RECORDING 8 0 0 0
2011-05-26 12:47:24.024 TVRec(11): ASK_RECORDING 11 0 0 0
2011-05-26 12:47:27.048 TVRec(7): Changing from None to RecordingOnly
2011-05-26 12:47:27.062 TVRec(7): HW Tuner: 7->7
2011-05-26 12:47:29.811 DVBSM(/dev/dvb/adapter0/frontend0): Stop() -- 
begin
2011-05-26 12:47:29.813 SM(/dev/dvb/adapter0/frontend0)::Stop: begin
2011-05-26 12:47:29.837 SM(/dev/dvb/adapter0/frontend0)::Stop: end
2011-05-26 12:47:29.845 DVBSM(/dev/dvb/adapter0/frontend0): Stop() -- end
2011-05-26 12:47:29.846 SM(/dev/dvb/adapter0/frontend0)::Stop: begin
2011-05-26 12:47:29.847 SM(/dev/dvb/adapter0/frontend0)::Stop: end
2011-05-26 12:47:29.855 DVBChan(7:/dev/dvb/adapter0/frontend0): Opening 
DVB channel
2011-05-26 12:47:29.857 DVBChan(7:/dev/dvb/adapter0/frontend0): Opening 
DVB channel
2011-05-26 12:47:29.863 DVBSM(/dev/dvb/adapter0/frontend0): Can measure 
Signal Strength
2011-05-26 12:47:29.871 DVBSM(/dev/dvb/adapter0/frontend0): Can measure 
S/N
2011-05-26 12:47:30.421 DVBSM(/dev/dvb/adapter0/frontend0): Can measure 
Bit Error Rate
2011-05-26 12:47:30.422 DVBSM(/dev/dvb/adapter0/frontend0), Warning: 
Cannot count Uncorrected Blocks
                         eno: Operation not supported (95)
2011-05-26 12:47:30.423 SM(/dev/dvb/adapter0/frontend0)::RemoveFlags: 
Seen() Match() Wait(UB,)
2011-05-26 12:47:30.423 DVBSM(/dev/dvb/adapter0/frontend0): 
DVBSignalMonitor::ctor initial flags Seen() Match() Wait(Sig,SNR,BER,)
2011-05-26 12:47:30.435 SM(/dev/dvb/adapter0/frontend0)::Start: begin
2011-05-26 12:47:30.436 SM(/dev/dvb/adapter0/frontend0)::Start: end
2011-05-26 12:47:30.455 
DTVSM(/dev/dvb/adapter0/frontend0)::SetDVBService(transport_id: 2302, 
network_id: 2, service_id: 52125):
2011-05-26 12:47:30.456 SM(/dev/dvb/adapter0/frontend0)::RemoveFlags: 
Seen(PMT,SDT,Crypt,) Match(PMT,SDT,Crypt,) Wait()
2011-05-26 12:47:30.457 SM(/dev/dvb/adapter0/frontend0)::AddFlags: Seen() 
Match() Wait(PMT,SDT,)
2011-05-26 12:47:30.458 SM(/dev/dvb/adapter0/frontend0)::AddFlags: Seen() 
Match() Wait(PMT,SDT,Pos,)
2011-05-26 12:47:30.461 SM(/dev/dvb/adapter0/frontend0)::AddFlags: Seen() 
Match() Wait(Sig,)
2011-05-26 12:47:30.476 SM(/dev/dvb/adapter0/frontend0)::RemoveFlags: 
Seen() Match() Wait(Pos,)
2011-05-26 12:47:30.539 AutoExpire: CalcParams(): Max required Free Space: 
12.0 GB w/freq: 14 min
2011-05-26 12:47:30.544 Started recording: "RHS Chelsea Flower Show": 
channel 7361 on cardid 7, sourceid 1
2011-05-26 12:47:31.031 DVBSM(/dev/dvb/adapter0/frontend0): UpdateValues 
-- Signal Locked
2011-05-26 12:47:31.085 SM(/dev/dvb/adapter0/frontend0)::AddFlags: 
Seen(PAT,) Match() Wait()
2011-05-26 12:47:31.086 SM(/dev/dvb/adapter0/frontend0)::AddFlags: Seen() 
Match(PAT,) Wait()
2011-05-26 12:47:31.096 SM(/dev/dvb/adapter0/frontend0)::AddFlags: 
Seen(SDT,) Match() Wait()
2011-05-26 12:47:31.112 DTVSM(/dev/dvb/adapter0/frontend0)::SetSDT(): tsid 
= 2302 orig_net_id = 2
2011-05-26 12:47:31.114 SM(/dev/dvb/adapter0/frontend0)::AddFlags: Seen() 
Match(SDT,) Wait()
2011-05-26 12:47:31.115 SM(/dev/dvb/adapter0/frontend0)::RemoveFlags: 
Seen() Match() Wait(Pos,)
2011-05-26 12:47:31.116 SM(/dev/dvb/adapter0/frontend0)::AddFlags: 
Seen(PMT,) Match() Wait()
2011-05-26 12:47:31.117 SM(/dev/dvb/adapter0/frontend0)::AddFlags: Seen() 
Match(PMT,) Wait()
2011-05-26 12:47:31.132 DVBSM(/dev/dvb/adapter0/frontend0): Stop() -- 
begin
2011-05-26 12:47:31.134 SM(/dev/dvb/adapter0/frontend0)::Stop: begin
2011-05-26 12:47:31.133 Updating status for "RHS Chelsea Flower Show" on 
cardid 7 (Tuning => Recording)
2011-05-26 12:47:31.182 SM(/dev/dvb/adapter0/frontend0)::Stop: end
2011-05-26 12:47:31.191 DVBSM(/dev/dvb/adapter0/frontend0): Stop() -- end
2011-05-26 12:47:31.192 SM(/dev/dvb/adapter0/frontend0)::Stop: begin
2011-05-26 12:47:31.193 SM(/dev/dvb/adapter0/frontend0)::Stop: end
2011-05-26 12:47:31.259 TVRec(7): rec->GetPathname(): 
'/home/mythtv/recordings/7361_20110526124700.mpg'

This is a snippet of the log from the backend starting to record the RHS 
Chelsea Flower Show from the BBC 1 CI channel.

So, the above log shows that:

- it switches to RecordingOnly and selects tuner 7.  It then sets the 
service to "transport_id: 2302, network_id: 2, service_id: 52125".  This 
is the "Showcase" channel from 11259.67 MHz vertical - i.e. the wrong 
channel.

- It logs that it has started recording "RHS Chelsea Flower Show" from 
channel 7361.  This programme name and channel number are correct - 
channel 7361 is BBC 1 CI.

- There is a further log line stating that SetSDT() is setting the tsid to 
2302 (the wrong transport ID).

>From my database, BBC 1 CI has the following attributes:
 	chanid = '7361'
 	channum = ''
 	freqid = NULL
 	sourceid = '1'
 	callsign = 'BBC 1 CI'
 	name = 'BBC 1 CI'
 	mplexid = '36'
 	serviceid = '6361'

And Showcase has these attributes:
 	chanid = '53125'
 	channum = '403'
 	freqid = NULL
 	sourceid = '1'
 	callsign = 'Showcase'
 	name = 'Showcase'
 	mplexid = '64'
 	serviceid = '52125'

Multiplex 36 has:
 	sourceid = '1'
 	transportid = '2045'
 	networkid = '2'
 	frequency = '10773250'
 	inversion = 'a'
 	symbolrate = '22000000'
 	fec = '5/6'
 	polarity = 'h'

Multiplex 64 has:
 	sourceid = '1'
 	transportid = '2302'
 	networkid = '2'
 	frequency = '11259670'
 	inversion = 'a'
 	symbolrate = '275000000'
 	fec = '2/3'
 	polarity = 'v'

This doesn't always happen - much of the time it records from the correct 
channel just fine, but it is quite frequent.

I'm using Mythtv 0.24 under Debian on an ARM with a Technotrend TT 
Connect S2-3600 USB DVB-S receiver.

Any help would be appreciated.

-- 

  - Steve
    xmpp:steve at nexusuk.org   sip:steve at nexusuk.org   http://www.nexusuk.org/

      Servatis a periculum, servatis a maleficum - Whisper, Evanescence