Mailing List Archive

Multiple tuners, multiple sources...
Haven't actually started building my Mythbox yet... Just wanted to clarify
an issue:

I'll be getting digital cable in the near future, with one receiver. I've
also got USDTV, which is an over-the-air HDTV receiver with a few
non-broadcast channels (Food Network, HDTV, etc.).

I'll be building my Mythbox with two tuners (probably two Avermedia M179).

I want to connect the digital cable receiver to one of the tuners. I'd like
to be able to connect both the USDTV (on S-video) AND my cable (on coax) to
the second tuner -- so that analog cable channels are available.

If I do that, that means that some channels (the broadcast networks, for
example) will be available from three sources: Tuner1, Tuner2-svid, and
Tuner2-coax.

Other channels will be available from two sources (Tuner1 and one of the
Tuner2 inputs)

And then there will be several channels that will only be available from
Tuner1.

Does Myth handle this kind of thing okay? I can set priorities on which
source to record from, right? Can I do this on a per-channel basis? (i.e.
Food Network over the USDTV will be better quality than the Digital Cable
Food Network, since it's HD, but Nickelodeon will be better on the Digital
Cable than on the Analog Cable (and not available at all on the USDTV).

TIA for clarification and information.
Scott


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Re: Multiple tuners, multiple sources... [ In reply to ]
On Thursday 11 March 2004 15:41, Scott Nicholson wrote:
> Haven't actually started building my Mythbox yet... Just wanted to
> clarify an issue:
>
> I'll be getting digital cable in the near future, with one receiver.
> I've also got USDTV, which is an over-the-air HDTV receiver with a
> few non-broadcast channels (Food Network, HDTV, etc.).
>
> I'll be building my Mythbox with two tuners (probably two Avermedia
> M179).
>
> I want to connect the digital cable receiver to one of the tuners.
> I'd like to be able to connect both the USDTV (on S-video) AND my
> cable (on coax) to the second tuner -- so that analog cable channels
> are available.
>
> If I do that, that means that some channels (the broadcast networks,
> for example) will be available from three sources: Tuner1,
> Tuner2-svid, and Tuner2-coax.
>
> Other channels will be available from two sources (Tuner1 and one of
> the Tuner2 inputs)
>
> And then there will be several channels that will only be available
> from Tuner1.
>
> Does Myth handle this kind of thing okay? I can set priorities on
> which source to record from, right? Can I do this on a per-channel
> basis? (i.e. Food Network over the USDTV will be better quality than
> the Digital Cable Food Network, since it's HD, but Nickelodeon will
> be better on the Digital Cable than on the Analog Cable (and not
> available at all on the USDTV).
>
> TIA for clarification and information.
> Scott

Man, what a complex situation! Just for clarification, you'd have 3
sources:

Analog cable
Digital cable
USDTV

with the following connections:

Digital cable -> SVideo0 or Composite0

Analog cable -> Tuner1
USDTV -> SVideo1

(and just to make things more complex, you could split your cable and
also hook up Analog Cable -> Tuner0, but we'll ignore that for now)

The good news is that, although having a channel duplicated in multiple
sources used to be a nightmare, CVS has (IIRC) the ability to correlate
channels in different sources, if they have the same callsign. This
means that, across all 3 sources, a channel with the callsign 'FOODTV'
is considered the same channel. However, 'FOODTV-HD' would be a
different channel. I'm not sure if that heuristic applies to the
scheduler or just the EPG view... if it doesn't affect the scheduler,
then you're out of luck.

Unfortunately, I don't think Myth currently has the capability to
indicate card preferences. So, if you want to record something on
FOODTV, you have 3 choices:

(1) name the channels in all 3 sources "FOODTV". Your recording might
end up using any one of the three sources

(2) name the digital & analog cable channel "FOODTV", but name the USDTV
channel "FOODTV-HD". Schedule the recording for either channel. If
you use "FOODTV", it will record from either digital or analog cable.
If you use "FOODTV-HD", it will record only on USDTV, or not at all.

(3) name the channels as in (2) above, but set up two identical
recordings -- one for "FOODTV" and one for "FOODTV-HD". Give the one
on "FOODTV-HD" a higher priority. Worst case, it records twice. Best
case (if you turn on duplicate detection & you have enough program
information), the lower priority one will be suppressed because the
scheduler knows it's being recorded elsewhere. Hey, it ain't pretty,
but it might work...

-JAC
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RE: Multiple tuners, multiple sources... [ In reply to ]
> > I want to connect the digital cable receiver to one of the tuners.
> > I'd like to be able to connect both the USDTV (on S-video) AND my
> > cable (on coax) to the second tuner -- so that analog cable channels
> > are available.
>
> Man, what a complex situation! Just for clarification, you'd have 3
> sources:
>
> Analog cable
> Digital cable
> USDTV
>
> with the following connections:
>
> Digital cable -> SVideo0 or Composite0
>
> Analog cable -> Tuner1
> USDTV -> SVideo1

Correct.

> (and just to make things more complex, you could split your cable and
> also hook up Analog Cable -> Tuner0, but we'll ignore that for now)

True... Hadn't thought of that.

Just to clarify... Myth does treat each input on each capture card as a
different source, right? (Obviously I can't record on both the SVideo and
the Tuner on the same card at the same time).

> The good news is that, although having a channel duplicated in multiple
> sources used to be a nightmare, CVS has (IIRC) the ability to correlate
> channels in different sources, if they have the same callsign. This
> means that, across all 3 sources, a channel with the callsign 'FOODTV'
> is considered the same channel. However, 'FOODTV-HD' would be a
> different channel. I'm not sure if that heuristic applies to the
> scheduler or just the EPG view... if it doesn't affect the scheduler,
> then you're out of luck.

It sounds like even if the scheduler isn't affected things are at least
moving in that direction?

> Unfortunately, I don't think Myth currently has the capability to
> indicate card preferences.

Any idea if this is something that may be added in the future? (Has it been
requested before / is it something the devs would be interested in
implementing?)

> ...
> (3) name the channels as in (2) above, but set up two identical
> recordings -- one for "FOODTV" and one for "FOODTV-HD". Give the one
> on "FOODTV-HD" a higher priority. Worst case, it records twice. Best
> case (if you turn on duplicate detection & you have enough program
> information), the lower priority one will be suppressed because the
> scheduler knows it's being recorded elsewhere. Hey, it ain't pretty,
> but it might work...

Makes sense...

Thanks for the feedback.
Scott

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Re: Multiple tuners, multiple sources... [ In reply to ]
what about 2 different inputs going to 2 different audio sources. my tuner
card uses the bttv audio module and i want to grab audio from there. but i
also want to use the composite input for my vcr to plug into but obviously i
can't grab audio from teh bttv audio module because the composite input
carriies no audio. there doesn't seemt o be a way to configure each input to
be paired with a particular audio input. there's jut one place for this
representing the whole card.

On Thursday 11 March 2004 06:24 pm, Scott Nicholson wrote:

> > > I want to connect the digital cable receiver to one of the tuners.
> > > I'd like to be able to connect both the USDTV (on S-video) AND my
> > > cable (on coax) to the second tuner -- so that analog cable channels
> > > are available.
> >
> > Man, what a complex situation! Just for clarification, you'd have 3
> > sources:
> >
> > Analog cable
> > Digital cable
> > USDTV
> >
> > with the following connections:
> >
> > Digital cable -> SVideo0 or Composite0
> >
> > Analog cable -> Tuner1
> > USDTV -> SVideo1
>
> Correct.
>
> > (and just to make things more complex, you could split your cable and
> > also hook up Analog Cable -> Tuner0, but we'll ignore that for now)
>
> True... Hadn't thought of that.
>
> Just to clarify... Myth does treat each input on each capture card as a
> different source, right? (Obviously I can't record on both the SVideo and
> the Tuner on the same card at the same time).
>
> > The good news is that, although having a channel duplicated in multiple
> > sources used to be a nightmare, CVS has (IIRC) the ability to correlate
> > channels in different sources, if they have the same callsign. This
> > means that, across all 3 sources, a channel with the callsign 'FOODTV'
> > is considered the same channel. However, 'FOODTV-HD' would be a
> > different channel. I'm not sure if that heuristic applies to the
> > scheduler or just the EPG view... if it doesn't affect the scheduler,
> > then you're out of luck.
>
> It sounds like even if the scheduler isn't affected things are at least
> moving in that direction?
>
> > Unfortunately, I don't think Myth currently has the capability to
> > indicate card preferences.
>
> Any idea if this is something that may be added in the future? (Has it been
> requested before / is it something the devs would be interested in
> implementing?)
>
> > ...
> > (3) name the channels as in (2) above, but set up two identical
> > recordings -- one for "FOODTV" and one for "FOODTV-HD". Give the one
> > on "FOODTV-HD" a higher priority. Worst case, it records twice. Best
> > case (if you turn on duplicate detection & you have enough program
> > information), the lower priority one will be suppressed because the
> > scheduler knows it's being recorded elsewhere. Hey, it ain't pretty,
> > but it might work...
>
> Makes sense...
>
> Thanks for the feedback.
> Scott
>
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stel valavanis http://www.onshore.com/
Re: Multiple tuners, multiple sources... [ In reply to ]
Scott Nicholson wrote:
>>>I want to connect the digital cable receiver to one of the tuners.
>>>I'd like to be able to connect both the USDTV (on S-video) AND my
>>>cable (on coax) to the second tuner -- so that analog cable channels
>>>are available.
>>
>>Man, what a complex situation! Just for clarification, you'd have 3
>>sources:
>>
>>Analog cable
>>Digital cable
>>USDTV
>>
>>with the following connections:
>>
>>Digital cable -> SVideo0 or Composite0
>>
>>Analog cable -> Tuner1
>>USDTV -> SVideo1
>
>
> Correct.
>
>
>>(and just to make things more complex, you could split your cable and
>>also hook up Analog Cable -> Tuner0, but we'll ignore that for now)
>
>
> True... Hadn't thought of that.
>
> Just to clarify... Myth does treat each input on each capture card as a
> different source, right? (Obviously I can't record on both the SVideo and
> the Tuner on the same card at the same time).

More clarifying ;-).

Source = provider for TV listings (CoxCable, CoxDigital)
Input = connector (coax, s-video)
Card = thing that cuts your fingers when you shove it in the slot.

You can use multiple inputs on a card and the scheduler knows
that can only record one thing at a time on a card. You can use
the same source for different inputs on different cards (or even
the same card) and the scheduler knows that it can record a show
from that source on any of those inputs. And you can have multiple
cards.

>>The good news is that, although having a channel duplicated in multiple
>>sources used to be a nightmare, CVS has (IIRC) the ability to correlate
>>channels in different sources, if they have the same callsign. This
>>means that, across all 3 sources, a channel with the callsign 'FOODTV'
>>is considered the same channel. However, 'FOODTV-HD' would be a
>>different channel. I'm not sure if that heuristic applies to the
>>scheduler or just the EPG view... if it doesn't affect the scheduler,
>>then you're out of luck.
>
>
> It sounds like even if the scheduler isn't affected things are at least
> moving in that direction?

Joseph is essentially correct but there has been a big move in
this direction that's pretty new so let me give it a shot =).

When 0.15 is released or in CVS now, the scheduler has two new
features for matching stations based on callsign and a feature
for adding priority preference values for inputs (ex. s-video
on card 2 can be given a higher value than coax on card 1) Using
both of these will allow you (and the scheduler) to do nifty
stuff.

If two or more things in the channel table have the same "callsign"
the scheduler will consider these to be the same broadcast station
with the same listing (you have to make sure that is true ;-).
These can be the same or different channel numbers on the same or
different source. As long as the callsign is the same it assumes
it has the same listings. The EPG was also hacXXX improved to
show just one of these channels rather than repeating the listings.
When you choose a show from that broadcast station, say FOOD, it
knows that it could record that show from any Source->Card->Input
that has "FOOD".

I'll guess wrong and say you have FOOD on HDTV channel 124 from
the card 2 svideo and FOOD on channel 44 for the analog and digital
inputs. You have three different sources with FOOD available on
four different inputs. So which will be chosen for "Iron Chef"?

In the backend "setup" program, you can go to Input Connections
and choose the input for HDTV on card 2 s-video. Change the Input
preference to "1". The scheduler adds this to the priority when
it's prioritizing. The result is that if Iron Chef has a priority
of 5, it will have priority 6 for the HDTV and 5 for all the others.

This means that it will alway try to record Iron Chef in HD.
However, if some other show with a higher priority already gets
the HDTV input, the scheduler will try to use one of the other
S/C/Is to record Iron Chef.

>>Unfortunately, I don't think Myth currently has the capability to
>>indicate card preferences.
>
>
> Any idea if this is something that may be added in the future? (Has it been
> requested before / is it something the devs would be interested in
> implementing?)

It is not in the current 0.14 release but will be in 0.15 and
has been in CVS for about two weeks.

>>...
>>(3) name the channels as in (2) above, but set up two identical
>>recordings -- one for "FOODTV" and one for "FOODTV-HD". Give the one
>>on "FOODTV-HD" a higher priority. Worst case, it records twice. Best
>>case (if you turn on duplicate detection & you have enough program
>>information), the lower priority one will be suppressed because the
>>scheduler knows it's being recorded elsewhere. Hey, it ain't pretty,
>>but it might work...

You would only want to add "-HD" if there were differences in
the schedules. Otherwise, use the same callsign and the the
Input preference will take care of the preferred input and can
fail-over to another input when necessary.

-- bjm
Re: Multiple tuners, multiple sources... [ In reply to ]
On Thursday 11 March 2004 19:43, Stelios Valavanis wrote:
> what about 2 different inputs going to 2 different audio sources. my
> tuner card uses the bttv audio module and i want to grab audio from
> there. but i also want to use the composite input for my vcr to plug
> into but obviously i can't grab audio from teh bttv audio module
> because the composite input carriies no audio. there doesn't seemt o
> be a way to configure each input to be paired with a particular audio
> input. there's jut one place for this representing the whole card.
>

Well, ordinarily I'd say connect the audio that goes along with your
composite video source to the line-in of your tuner card; you shouldn't
have to reconfigure anything else.

However, you didn't specify exactly what model of tuner card you have...
there are some low-end bttv cards that don't have a line-in, in which
case you're kind of out of luck if you want to use more than one input
on the card with Myth. You'd have to connect the audio from your 2nd
video source directly to your sound card line-in, but since Myth can
currently only associate a single audio recording device with a card,
you'd have to choose between your btaudio device and your sound card.

You might be able to hack something together using some fancy external
channel-change scripts that update a symbolic link to your two actual
dsp devices, or if you're adventurous you could write a patch for Myth
that would allow an audio capture device to be associated with each
input on a card, rather than the card as a whole.

-JAC
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