[mythtv-users] How do you "tune" subchannels in QAM?

Fri Apr 1 18:19:44 UTC 2005

John,

The transports page gets filled out during the scan.
However, what is shown on the dvb transport editor page is
561000000 Hz (0) (0) (0)
567000000 Hz (0) (0) (0)
573000000 Hz (0) (0) (0)
579000000 Hz (0) (0) (0)
585000000 Hz (0) (0) (0)
Etc..

When I chose to scan existing transport, just like Adam, it stays at:
Status : Scanning Signal Locked
Scan Activity: 5% hangs here forever.
Signal Strength: fluctuates between 1 and 3 % with an occasional spike to
99%
Signal/Noise: 99% solid. Never changes.

If I take a look at the terminal window I see
2005-04-01 12:21:35.952 DVB#0 DVB SI Table Parser Started
2005-04-01 12:21:35.952 DVB#0 Using DVB card 0, with frontend pcHDTV HD3000
HDTV.
2005-04-01 12:21:35.952 DVB#0 DVB Signal Monitor Starting
2005-04-01 12:21:37.411 DVB#0 DVB signal f8d4 | snr fdef | ber    0 | unc
0
2005-04-01 12:21:37.541 DVB#0 Signal Locked
2005-04-01 12:21:37.779 DVB#0 Status: LOCK.
Setting currenTID = 9
2005-04-01 12:21:58.313 DVB#0 Signal Lost
2005-04-01 12:21:58.820 DVB#0 Signal Locked
2005-04-01 12:27:48.936 DVB#0 Signal Lost
2005-04-01 12:27:49.452 DVB#0 Signal Locked

As you can see it scanning the same transport for 6 mins with no results.

Mplexid 9 is 573000000 Hz, or c82.
yggdrasil root # azap -c /root/channels.conf-qam-correct -r c82
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 573000000 Hz
video pid 0x0000, audio pid 0x0000
status 1f | signal 0977 | snr fded | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0977 | snr fdff | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0977 | snr fdeb | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0977 | snr fded | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0394 | snr fde5 | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0394 | snr fdb1 | ber 00000000 | unc 00000000 |
FE_HAS_LOCK

dvbscan shows 2 valid programs.

yggdrasil root # dvbscan -cvvv
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
parse_section:981: pid 0x00 tid 0x00 table_id_ext 0x80b6, 0/0 (version 2)
PAT
parse_section:981: pid 0x31 tid 0x02 table_id_ext 0x0002, 0/0 (version 0)
PMT 0x0031 for service 0x0002
  VIDEO     : PID 0x0840
  OTHER     : PID 0x0841 TYPE 0x81
parse_pmt:798: 0x0000 0x0002: (null) -- (null), pmt_pid 0x0031, vpid 0x0840,
apid 0x0000 ()
parse_section:981: pid 0x30 tid 0x02 table_id_ext 0x0001, 0/0 (version 4)
PMT 0x0030 for service 0x0001
  VIDEO     : PID 0x0800
  OTHER     : PID 0x0801 TYPE 0x81
  OTHER     : PID 0x0802 TYPE 0x81
parse_pmt:798: 0x0000 0x0001: (null) -- (null), pmt_pid 0x0030, vpid 0x0800,
apid 0x0000 ()
WARNING: filter timeout pid 0x0011
dumping lists (2 services)
[0001]                   (0x0001) 00: PCR == V   V 0x0800
[0002]                   (0x0002) 00: PCR == V   V 0x0840
Done.

Dvbtraffic shows
yggdrasil root # dvbtraffic
0000     3 p/s     0 kb/s     5 kbit
0030    19 p/s     3 kb/s    29 kbit
0031    19 p/s     3 kb/s    29 kbit
0800 10284 p/s  1888 kb/s 15467 kbit
0801   260 p/s    47 kb/s   391 kbit
0802    89 p/s    16 kb/s   134 kbit
0840 11078 p/s  2033 kb/s 16662 kbit
0841   266 p/s    48 kb/s   400 kbit
1fff  3780 p/s   693 kb/s  5685 kbit
2000 25804 p/s  4737 kb/s 38809 kbit
-PID--FREQ-----BANDWIDTH-BANDWIDTH-

I have a feeling that myth is getting stuck on PID 0000 fails to tune it and
this is where it all ends. Gonna try to find the scan routine in source and
see if it starts at 0000 and if it does change it to 0001 and see what
happens.

Marc

-----Original Message-----
From: mythtv-users-bounces at mythtv.org
[mailto:mythtv-users-bounces at mythtv.org] On Behalf Of John Sturgeon
Sent: Friday, April 01, 2005 10:39 AM
To: Discussion about mythtv
Subject: Re: [mythtv-users] How do you "tune" subchannels in QAM?

Marc Tousignant wrote:

>>Have you been able to successfully tune the frequencies using azap? (get 
>>the instructions for installing it here: 
>>http://www.rsmas.miami.edu/personal/angel/mythtv/air2pc-howto.html) 
>>
>>You might try just getting your card to successfully tune the channels, 
>>and as a worst case scenario, use the frequencies reported by azap for 
>>your channels in the DVB Transports section of the MythTV configuration.
>>
>>But first, just to rule out problems with your driver setup, you need to 
>>make sure azap works.
>>    
>>
>
>John
>
>Azap works to tune channels and Dvbscan confirms there are subchannels
>
>yggdrasil root # azap -c /root/channels.conf-qam-correct -r c82
>using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
>tuning to 573000000 Hz
>video pid 0x0000, audio pid 0x0000
>status 1f | signal 0977 | snr fded | ber 00000000 | unc 00000000 |
>FE_HAS_LOCK
>status 1f | signal 0977 | snr fdd5 | ber 00000000 | unc 00000000 |
>FE_HAS_LOCK
>status 1f | signal 0977 | snr fded | ber 00000000 | unc 00000000 |
>FE_HAS_LOCK
>
>  
>
[snip]

>You got any better ideas I'm open to trying.
>
>Got home and tried the channel I setup. It plays.. Kinda.. it's almost as
if
>something within mythtv itself is interfering with the signal or hampering
>playback. I get massive pixelization and the audio skips so much you can't
>hear anything understandable.
>
>Feeding from dvbstream to videolan works flawlessly through my network.
>Both my myth system (yggdrasil) and my gaming system (nidheg) are P4
>3.40GHz's with GeForce FX 5700LE's
>The key differences between them are; nidheg has an audigy card and 1 gig
>ram and yggdrasil has the capture cards, PVR-350 and HD3000, and 512 meg
>ram.
>Ya overkill but yggdrasil is intended to be front/back and a transcoder
with
>all intentions of lasting a long time.
>
>Marc
>  
>

What happens if you set up the frequencies that get reported by azap in 
the DVB Transports section, then under scan for channels, you select 
"Scan existing transports"? 
For a bit more detail see: http://www.digitalregime.com/mythdvb/setup/

-- 
John Sturgeon <><
http://www.sturgeonfamily.com/mythtv.php

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