[pvrusb2] mythtv and wintv-hvr-1950 - analog/digital scanning

[fivenote]

Thanks Mike.

I think I am telling it QAM mode. In myth TV backend config I choose
"us-cable" as the "Channel frequency table". I'm doing exactly as I
did yesterday when it found all the cable channels. Only thing I
changed was to compile the latest v4l drivers from
http://linuxtv.org/hg/v4l-dvb. After that the DVB/broadcast channels
started working and MPEG/cable channels disappeared.

My developer's sense (I'm a web app developer) says the fix for the
DVB broke the analog side. Please feel free to pass this on to the DVB
develpoers.

BTW... overall the developers that contribute here are doing a great
job. I'm excitied to be so close to having this all work.

-vincent

On Sun, Jan 4, 2009 at 9:39 PM, Mike Isely <isely at isely.net> wrote:
> On Sun, 4 Jan 2009, fivenote wrote:
>
>> Mike,
>>
>> Thanks so much. Your explanation made sense. I got the latest v4l
>> driver source from linuxtv.org. It compiled and installed ok. I
>> noticed it came with a version of pvrusb2 so I used that instead of
>> the pvrisb2 I had compiled separately before.
>>
>> Now I get tons of HD ATSC channels. But I lost my cable channels. I
>> scanned the input connection for [MPEG : /dev/video0] and get all "no
>> signal". I had all my expected channels before upgrading the v4l
>> drivers and now none. I checked the myth and system logs,but nothing
>> obvious.
>>
>> That figures, doesn't it? One day you got cable and no ATSC, the next
>> day all ATSC and no cable.
>>
>> Is the scan and lock for the cable channels likely an issue with the
>> same tda18271.ko?
>
> Cable broadcasts as I understand it are QAM not ATSC.  Probably
> somewhere you need to tell MythTV it is dealing with a cable signal so
> that the tuner can drop into QAM mode.
>
> At least that's a guess.  I don't get cable here (I *HATE* the cable
> companies) so I don't know this for a fact.  But it's what I understand
> about digital cable reception.  The modulation standard is different and
> the tuner has to know to look for this.  Why is this the case?  I have
> no idea; seems stupid to me to have different modulation standards for
> cable versus over-the-air.
>
> If you know the tuner (i.e. tda18271.ko) is running in QAM mode then you
> may have hit a new problem - and if that is the case I know a couple DVB
> developers who will want to hear about this.
>
>  -Mike
>
> --
>
> Mike Isely
> isely @ pobox (dot) com
> PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8
>



--
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VAO - fivenote at gmail.com
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-- 
~~~~~~~~~~~~~~~~~~~~
VAO - fivenote at gmail.com
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