[mythtv-users] Silly question about live tv and two tuners

Josu Lazkano josu.lazkano at gmail.com
Wed Aug 17 17:35:46 UTC 2011

2011/8/17 Michael T. Dean <mtdean at thirdcontact.com>:
> On 08/17/2011 11:41 AM, Ronald Frazier wrote:
>> On Wed, Aug 17, 2011 at 8:29 AM, Martin Moores wrote:
>>> Interesting.  I remember reading on this list about adding tuners first,
>>> then virtual tuners afterwards, as Nick mentioned.  But the Wiki does indeed
>>> suggest otherwise and the way it describes makes sense.
>> If you only set it to 2 simultaneous recordings, then the physicals
>> first/virtuals after setup makes sense. In the link I posted above,
>> note the 3rd paragraph where it talks about live TV. If you setup your
>> tuners in the following order
>> Tuner 1 - Physical
>> Tuner 1 - Virtual
>> Tuner 2 - Physical
>> Tuner 2 - Virtual
>> the problem would be that if you enabled the "avoid conflicts in live
>> tv" setting, and if you have 2 frontends watching live tv at the same
>> time, then each machine is going to default to one of the last 2
>> tuners, and they will end up sharing a physical tuner. If you order
>> them as follows:
>> Tuner 1 - Physical
>> Tuner 2 - Physical
>> Tuner 1 - Virtual
>> Tuner 2 - Virtual
>> Then you solve the live tv issue, but now you introduce the problem
>> that myth won't try to use the virtual tuner for the 2nd recording.
>> The better way to set it up would be
>> Tuner 1 - Physical
>> Tuner 1 - Virtual 1
>> Tuner 2 - Physical
>> Tuner 2 - Virtual 1
>> Tuner 1 - Virtual 2
>> Tuner 2 - Virtual 2
>> This way, when recording, myth will always try to grab a tuner that's
>> already tuned to the same multiplex (when possible), and live TV will
>> always try to grab a tuner that's not used by another livetv session.
> Good summary.
> It seems a lot of people have wrongly paraphrased the approach I once
> described--heretofore known as the "Break your system by configuring
> MythTV to prefer Live TV over recordings" approach--and in so doing have
> recommended to a lot of users on other forums that they completely
> destroy their setup with alternating tuners (a "1+1" setup).
> My original post is at
> http://www.gossamer-threads.com/lists/mythtv/dev/369358#369358 .  If you
> consider doing this--using the "Break your system by configuring MythTV
> to prefer Live TV over recordings" approach--you should read and
> understand the details of the entire post and use the final approach
> mentioned.  You should also bear in mind that it's best described as the
> "Break your system by configuring MythTV to prefer Live TV over
> recordings" approach.
> Note that following those instructions /will/ break your configuration
> and may result in lost recordings.  However, if you truly feel that Live
> TV is more important than recordings--and that hitting a single key
> (NEXTCARD) is more work than you can bear--it's the approach you'd need
> to take.
> Note also how I /never/ said to alternate tuners.  I said to configure
> /3/ tuners per card, then go back and add one to each card after.  Also,
> it assumes 3 physical capture cards.  With only 2 capture cards, it is
> guaranteed to cause problems eventually.
> The alternating tuner approach will completely destroy scheduling.
> Having 2 tuners per card then adding one is better than 1+1, but still
> may cause more problems than 3+1 or 4+1.
> That said, remember that MythTV--out of the box--will do the right thing
> to ensure recordings are more important than Live TV and that the "Break
> your system by configuring MythTV to prefer Live TV over recordings"
> configuration will break scheduling in some circumstances (even with a
> 3+1 or 4+1 config).
> The /right/ approach for Live TV users is to use the NEXTCARD binding to
> switch cards when you enter Live TV and it's locked to a multiplex and
> you want to watch something Live on another multiplex at the risk of
> losing one or more recordings.  The best approach for minimizing the
> risk is to have sufficient physical tuners that you don't have to
> worry.  If you have 10 physical tuners in your system, your risk of
> losing recordings due to Live TV is significantly smaller than if you
> have 2 physical tuners in your system--to the point that I recommend no
> one should use the "Break your system by configuring MythTV to prefer
> Live TV over recordings" approach without at least 3 physical tuners.
> The /best/ approach for ensuring you can record and watch everything you
> want with the most-efficient tuner assignment is to /not/ use the "Break
> your system by configuring MythTV to prefer Live TV over recordings" and
> instead record everything you might possibly ever want to watch (with
> recording rules, not Live TV) and never use Live TV.  See, also,
> http://www.gossamer-threads.com/lists/mythtv/users/387302#387302 for
> details on why /everything/ should be a scheduled recording--even news
> and sports broadcasts.  In other words, the best approach is to use
> MythTV as a DVR--a Digital Video *Recorder*.
> Remember,  the 3+1 or 4+1 approach is known as the "Break your system by
> configuring MythTV to prefer Live TV over recordings," and it does break
> it--even if you don't notice the consequences.  (But if you're going to
> use it, please at least do it right--never 1+1; 2+1 is better; 3+1 or
> 4+1 is preferred; and ensure you have sufficient physical tuners (3 or
> more) to reduce the chance of lost recordings to a level you can tolerate)
> Mike
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Hello, I had this problem too. So I decide to add 4 adapters (2 DVB-S2
and 2 DVB-T), then I just configure 1 recording for each tuner and now
I have no problem to LiveTV.

I really like LiveTV, and it was so difficult for me to change the
input every LiveTV channel change. Now I have no problem. Maybe this
is not the ideal configuration, but it works for me.

It will be great to add a function to select the right adapter.

Best regards.

Josu Lazkano

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