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HD-5500 trying to capture QAM over cable
PostPosted: Mon Jan 08, 2007 10:49 pm Reply with quote
guinan
 
Joined: 07 Jan 2007
Posts: 2




Hi,

I just got an HD-5500, and I'm trying to get up and running. I've been
browsing these forums, and made some progress, but I haven't yet
been able to reach my initial goal, which is to capture and view QAM
channels over cable. My neighbor has the same cable provider, and his
HDTV set's built-in tuner picks up a number of unencrypted channels, so
I'm guessing its possible.

Here's where I am so far...

Xyzzy's atscscan finds a lot of channels,

$ ./atscscan.xyzzy -c 80 135
Tuning to channel 80 (561.0000 MHz): ###### Unable to tune channel
Tuning to channel 81 (567.0000 MHz): # LOCK Strength = 0.0%
Program 2: 81.2 (No PSIP data) PMT 0047h
Stream 0: PID 0040h MPEG-2 Video (02h)
Stream 1: PID 0041h AC-3 Audio (81h)
Program 3: 81.1 (No PSIP data) PMT 0057h
Stream 0: PID 004bh MPEG-2 Video (02h)
Stream 1: PID 004ch AC-3 Audio (81h)
Tuning to channel 82 (573.0000 MHz): # LOCK Strength = 0.0%
Program 2: 82.5 (No PSIP data) PMT 0047h
Stream 0: PID 0042h MPEG-2 Video (02h)
Stream 1: PID 0043h AC-3 Audio (81h)
Program 3: 82.3 (No PSIP data) PMT 0057h
Stream 0: PID 005ch DCII Video (80h)
Stream 1: PID 005dh AC-3 Audio (81h)
...

In total I see 74 MPEG-2 streams, and 87 DCII streams. I understand
that the DigiCipher streams are encrypted, so I'll ignore them.

I also get good results from CVS dvb-apps,

$ ./dvbscan atsc/us-Cable-Standard-center-frequencies-QAM256
(wait several minutes...)
[0002]:567000000:QAM_256:64:65:2
[0001]:567000000:QAM_256:75:76:1
[0005]:573000000:QAM_256:66:67:5
[0003]:573000000:QAM_256:0:93:3
...
(126 channels total)

dtvscan (built from dvb-atsc-tools-1.0.4 source) only works for a single
channel, or the first channel when a range is specified,

$ dtvscan -q -c 81:100
dtvscan ver 1.0.4 - by Jack Kelliher (c) 2002,2005,2006
Attempting to open /dev/dtv
Opened FE:/dev/dvb/adapter0/frontend0 3
Opened DMX:/dev/dvb/adapter0/demux0 4
Opened DVR:/dev/dvb/adapter0/dvr0 5
channel = 81 QAM_256
Signal: 3101
look for sync
1252 packets
PAT found
4657 packets
PAT found
7552 packets
PAT found
PAT found
38048 packets
PAT found
Unable to recieve valid packets
did find pat
`ERROR vct item ptr null couldn't get channel info
: :81.1 :81: 2:1

channel = 82 QAM_256
channel = 82 QAM_64
channel = 83 QAM_256
channel = 83 QAM_64
...

If I start again at 82, I see similar output, then nothing for 83, etc.

One odd thing is that azap shows "signal 0000", but a high snr,

$ azap -c zap.conf -r [0002]
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 567000000 Hz
video pid 0x0040, audio pid 0x0041
status 00 | signal 0000 | snr 0000 | ber 00000000 | unc 0000ffff |
status 1f | signal 0000 | snr fed4 | ber 00000000 | unc 0000ffff | FE_HAS_LOCK
status 1f | signal 0000 | snr fec7 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal 0000 | snr feda | ber 00000000 | unc 00000000 | FE_HAS_LOCK
...

Anyway, it looks like there's plenty of stuff "on the wire", so I've tried the
following,

$ cat ~/.mplayer/channels.conf
C81.2:567000000:QAM_256:71+64:65:2
C81.1:567000000:QAM_256:87+75:76:1
...

$ mplayer dvb://C81.2
dvb_tune Freq: 567000000
TS file format detected.
NO VIDEO! NO AUDIO! NO SUBS (yet)!
No stream found.
dvb_streaming_read, attempt N. 1 failed with errno 0 when reading 1612 bytes
dvb_streaming_read, attempt N. 1 failed with errno 0 when reading 4096 bytes
dvb_streaming_read, return 0 bytes

$ getatsc -q 81.2 > 81.2.out
[ctrl-c after some seconds ]

$ vlc 81.2.out
libdvbpsi error (PSI decoder): TS discontinuity (received 12, expected 0) for PID 71
libdvbpsi error (PSI decoder): TS discontinuity (received 6, expected 0) for PID 87

Interestingly, vlc seems to walk the stream for 10 seconds if I record for
10 seconds, even though it doesn't display any video or audio. And the
"View->Stream and Media Info" options shows the substreams,

http://www.bluebutton.com/misc/vlc-cap.png

So I've gotten this far, and my initial goal is to capture and view a video
stream. Any suggestions/clues?

My system is gentoo/amd64, btw. I have USE="... dvb".

-Jamie
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PostPosted: Thu Jan 11, 2007 8:24 am Reply with quote
guinan
 
Joined: 07 Jan 2007
Posts: 2




Update - I found one free-to-cable SD mpeg-TS stream. Still not sure what's up with the other channels, maybe they are encrypted even though they are advertised as MPEG-2 not DCII (which I would expect to be encrypted).

So I've got the HD5500 getting at least one DVB QAM channel, all the NTSC channels, and in time I expect to see some broadcast ATSC channels. Overall I'm happy.

-Jamie
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HD-5500 trying to capture QAM over cable
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