[mythtv] QAM tuning problem with HD-3000 & kernel DVB drivers
Bruce Pennypacker
bruce at pennypacker.org
Thu Jun 2 15:39:17 UTC 2005
> If this has already been answered sorry but I am catching up on the -dev list
> after a few days of ignoring it.. Are you using hte DVB drivers for starters?
> (I have to assume you are if you are scaning).. Can you tune to some
> multiplexes where you know channels are and see if you can find an VCTs (i.e.
> data on PID 0x1FFB).. Some cable systems don't send VCTs from what I have
> gathered from the list and when the scaning app gets no meta data it just bails
> out and gives up.. I need to change this, but I need to know if you are getting
> VCTs very slowly, or if they are just not present at all..
Yes, I'm using DVB. I'm using the HD-3000 DVB support built into the
2.6.11-rc3 kernel. (cx88-dvb module?)
I'm a real neophyte when it comes to all the DVB terminology so bear
with me but it looks like there's data on PID 0x1FFB. Using the
linuxtv.org dvb-apps I have the following entry in my channels.conf:
C82:573000000:QAM_256:0:0
If I run "azap -r C82" it shows a signal lock. I then run dvbtraffic
and its output contains:
-PID--FREQ-----BANDWIDTH-BANDWIDTH-
...
0800 1685 p/s 309 kb/s 2535 kbit
0801 131 p/s 24 kb/s 197 kbit
0802 69 p/s 12 kb/s 104 kbit
0840 2063 p/s 378 kb/s 3103 kbit
0841 132 p/s 24 kb/s 199 kbit
0842 67 p/s 12 kb/s 101 kbit
0880 2390 p/s 438 kb/s 3594 kbit
0881 130 p/s 23 kb/s 196 kbit
0882 68 p/s 12 kb/s 103 kbit
...
1fff 1530 p/s 280 kb/s 2302 kbit
2000 25804 p/s 4737 kb/s 38809 kbit
If I then modify my channels.conf using the PID's 880 & 881 (converted
to decimal) to this:
C82:573000000:QAM_256:2176:2177
Then after running azap on this channel I can pipe
/dev/dvb/adapter0/dvr0 to mplayer and view the channel.
Another thing I found is that if I run azap on an OTA channel while
hooked up to an antenna then dvbscan will show output like this:
$ dvbscan -c
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
service is running. Channel number: 25:1. Name: 'FOX Television Boston MA'
dumping lists (1 services)
FOX Television Boston MA (0x0003) 00: PCR == V V 0x0031 A 0x0034 (eng)
0x0034 (eng)
Done.
But if I have the cable hooked up and do the same on a QAM channel that
I've identified then the output is more like this:
$ dvbscan -c
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
WARNING: filter timeout pid 0x1ffb
dumping lists (11 services)
[0002] (0x0002) 00: PCR 0x0800 A 0x0801
0x0802 (spa)
[000b] (0x000b) 00: PCR 0x0840 A 0x0841
0x0842 (spa)
[0009] (0x0009) 00: PCR 0x0880 A 0x0881
0x0882 (spa)
[0008] (0x0008) 00: PCR 0x08c0 A 0x08c1
0x08c2 (spa)
[0003] (0x0003) 00: PCR 0x0900 A 0x0901
0x0902 (spa)
[0007] (0x0007) 00: PCR 0x0940 A 0x0941
0x0942 (spa)
[0001] (0x0001) 00: PCR 0x0980 A 0x0981
0x0982 (spa)
[000a] (0x000a) 00: PCR 0x09c0 A 0x09c1
0x09c2 (spa)
[0004] (0x0004) 00: PCR 0x0a00 A 0x0a01
0x0a02 (spa)
[000c] (0x000c) 00: PCR 0x0a40 A 0x0a41
0x0a42 (spa)
[0006] (0x0006) 00: PCR 0x0a80 A 0x0a81
Done.
> I will be glad to assist you, but chances are I will be digging into this for
> the next few days since my 5th gen Air2PC should be here tomorrow and I want to
> make it work with Cable as well as 8VSB since thats what is specd out to do..
I'll be more than happy to do whatever testing you might need. As I
said before I don't know much about DVB, etc. but I used to develop
telephony software so I'm used to debugging in realtime streaming
environments. I've got no problems firing up gdb & tracing through
things as long as you give me a good idea of what you're looking for.
Feel free to e-mail me directly whenever you're done with the Air2PC work.
-Bruce
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