[mythtv-users] ATSC channel not detected with ATI TV Wonder 600

[Douglas Paul]

On Fri, Jan 03, 2020 at 01:36:18PM -0500, Will Dormann wrote:
> Is it possible that this station is broadcasting in a way that isn't
> compatible with the TV Wonder 600, or the related software that is using
> it?   Or perhaps that the TV Wonder 600 just isn't good at receiving TV
> on channel 23?

There are some tools that I find useful for checking out the reception
and to see what the station is transmitting. In Gentoo, these are in the
media-tv/linuxtv-dvb-apps package. Should be available in other distros,
too, of course.

You can manually tune the station using 'azap' and see how the signal
quality is. To do that you can create a file ~/.azap/channels.conf with
this in it (for your examples):

WPXI:527028615:8VSB:49:51:1
WDKA:539028615:8VSB:49:51:1

The first number is the frequency in Hz (the offset seems to work best
with my HVR-950q, you may or may not need it). The numbers at the end
are for the subprogram information, and these don't need to be right for
the test.

Then you can tune it with azap using the channel name. You might do:

$ azap WPXI

And if it is working, you should see something like this:

using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
Version: 5.11  	 FE_CAN { ATSC + DVB-C (B) }
tuning to 593028615 Hz
video pid 0x0031, audio pid 0x0033
status 00 | signal 541d | snr 0073 | ber 000000ff | unc 000000ff |
status 1f | signal a83a | snr 00e6 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal a83a | snr 00e6 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal a83a | snr 00f0 | ber 00000000 | unc 00000000 | FE_HAS_LOCK

You should see a ber and unc of all zeros, with a stable FE_HAS_LOCK, if
you are receiving the channel fine.

You then leave that running to keep the tuner active, and in another
terminal, you can run dvbtraffic. You should see a dump of the traffic
on each PID, like this:

$ dvbtraffic
0000     9 p/s     1 kb/s    14 kbit
1010     9 p/s     1 kb/s    14 kbit
1011 12316 p/s  2261 kb/s 18524 kbit
1014   277 p/s    50 kb/s   416 kbit
1f00     3 p/s     0 kb/s     5 kbit
1f01     1 p/s     0 kb/s     2 kbit
1f02     1 p/s     0 kb/s     2 kbit
1f03     0 p/s     0 kb/s     1 kbit
1ffb    19 p/s     3 kb/s    29 kbit
1fff    30 p/s     5 kb/s    46 kbit
2000 12673 p/s  2326 kb/s 19060 kbit
-PID--FREQ-----BANDWIDTH-BANDWIDTH-
0000     9 p/s     1 kb/s    14 kbit
1010     9 p/s     1 kb/s    14 kbit
1011 12735 p/s  2338 kb/s 19153 kbit
1014   285 p/s    52 kb/s   429 kbit
1f00     2 p/s     0 kb/s     4 kbit
1f01     1 p/s     0 kb/s     2 kbit
1f02     0 p/s     0 kb/s     1 kbit
1f03     1 p/s     0 kb/s     2 kbit
1ffb    22 p/s     4 kb/s    34 kbit
1fff    31 p/s     5 kb/s    47 kbit
2000 13102 p/s  2405 kb/s 19705 kbit
-PID--FREQ-----BANDWIDTH-BANDWIDTH-

I'm in Canada, and we don't normally have subchannels here. So, you will
like have more PIDs with significant traffic than I show here. The PID
2000 is the sum of all the others -- and you should have about 19300
kbit if you're receiving everything without errors.

Another useful tool is dvbsnoop (media-video/dvbsnoop), that can show
you what the PIDs are for:

$ dvbsnoop -s pidscan
dvbsnoop V1.4.50 -- http://dvbsnoop.sourceforge.net/

---------------------------------------------------------
Transponder PID-Scan...
---------------------------------------------------------
PID found:    0 (0x0000)  [SECTION: Program Association Table (PAT)]
PID found: 4112 (0x1010)  [SECTION: Program Map Table (PMT)]
PID found: 4113 (0x1011)  [PS/PES: ITU-T Rec. H.262 | ISO/IEC 13818-2 or ISO/IEC 11172-2 video stream]
PID found: 4116 (0x1014)  [PS/PES: private_stream_1]
PID found: 7936 (0x1f00)  [SECTION: ATSC reserved]
PID found: 7937 (0x1f01)  [SECTION: ATSC reserved]
PID found: 7938 (0x1f02)  [SECTION: ATSC reserved]
PID found: 7939 (0x1f03)  [SECTION: ATSC reserved]
PID found: 8187 (0x1ffb)  [SECTION: ATSC reserved]
PID found: 8191 (0x1fff)  [stuffing]

You should always see a PAT and PMT (one PMT per channel). There is one
channel here, so there are two elementary streams: 0x1011 for the video
and 0x1014 for audio. The ATSC reserved PIDs are for things like EIT and
the virtual channel mapping.

When you're done with dvbsnoop and dvbtraffic, you can ctrl-C on the
azap terminal to release the tuner.

In any case, those tools should hopefully give you enough information to
see if the station is transmitting correctly and if it is missing the
needed tables for a full scan to work correctly. Then you should
hopefully be able to narrow it down to a signal that isn't strong
enough, or too much noise, etc.

Hope this helps,

-- 
Douglas Paul