[mythtv-users] MythTV and TV
yan at seiner.com
Mon Jan 30 18:31:45 UTC 2006
R. G. Newbury wrote:
>You cannot just change the Input Connection if the Source is a different
>The order in which things are done in mythtv-setup is slightly
>misleading in that a user can infer that the *card* is the most
>important part of the process. Actually the *lineup* is the most important.
>The channel lineup, at least for North American users, will
>differentiate among cable, cable digital and broadcast. Labs.zap2it.com
>will allow you ONE lineup of each of those types. Each of those has
>different connotations: 'cable' runs from 2 to 71 or so,
>'cable-digital' has "channel numbers" which run up to 999 I guess, but
>the frequencies involved are all actually the same range as 'cable' but
>with subchannels. Broadcast can be analog or digital. Broadcast digital
>is handled in a similar manner to cable-digital, but the numbering
>scheme is different.
>Cards handle either analog or digital streams (NTSC or ATSC), BUT NOT
>BOTH AT THE SAME TIME.
>That differentiation also determines what tuning information ( a 'tuning
>set') that mythtv sends to the card. Changing the information in mythtv,
>without any change to the lineup can produce a useless tuning set. I
>don't know what your card is, but if you are using an HD level (ATSC)
>card for OTA, then no wonder it will not work properly if you tell the
>card (through myth) that it should tune as if the input were a cable
>channel. Although transmission frequencies are the same for analog
>broadcast and analog cable channels and the underlying frequency may be
>the same for an HD digital broadcast, the manner in which the card
>abstracts the digital stream is quite different for a digital broadcast.
>To get an analog stream (channel 9 not channel 9_1) needs an analog
>module setup. ( For the pcHD3000, you use cx88_dvb for ATSC, and cx8800
>Digital broadcast is not the same thing as Analog broadcast and requires
>not only a different kernel module for the card but also a different
>setup in myth even if the lineup is still the same.
>Note also, that if the lineup type remains the same, you will run into
>problems if that lineup includes both analog and digital channels, since
>myth does not actually know that a card cannot do both. You must set up
>lineup <-> card pairings where that card can actually tune all of the
>channels in that lineup. So a PVR500 should never be paired against a
>cable-digital lineup or a broadcast lineup which includes digital
>channels: it cannot tune those channels. Similarly, a pcHD3000 should
>not be paired with a lineup which includes analog channels unless the
>card is set up to use an analog tuning module...
>And as far as I can tell, you cannot switch modules, 'on-the-fly' while
>myth is running, since myth checks each input card on startup, and would
>fail when it did not find the 'other' type of input.
Thanks. I finally got around to reading this in peace. Lots of good
The card I have currently is in fact an analog card - bt878, and, as
from my previous posting, I had digital channels mixed in there. So I
will set it up accordingly.
I also have a pcHDTV 3000 coming next week; I will set it up to receive
digital channels. It's good to know that I have to set it up for one or
the other; I am very new to this part of Mythtv....
My hope is to be able to use both cards simultaenously, but for now I
will be happy to get one to work... :-)
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