[mythtv-users] Live TV playback frustration

[Michael T. Dean]

On 08/24/2012 03:29 PM, Joseph Fry wrote:
>> Again, notifying the user and letting them /choose/ to exit Live TV and
>> watch the in-progress/previously-**recorded version of the episode would
>> be a good thing.  But it needs to be a conscious decision the user makes
>> and not some "I'll just force you out of Live TV" approach.  And, FWIW,
>> reserving a tuner but not using it is a waste.  And, yes, with that
>> statement, I'm *also* implying that Live TV itself is, by definition, a
>> waste (because it reserves a tuner and potentially records something that's
>> already being recorded)...  :)  There's no way to make Live TV not be a
>> waste because the implied contract of control involves wasting resources on
>> Live TV.  (Thus my--possibly over-the-top--distaste for Live TV.)
>
> Reserving a tuner is far less wasteful than recording two copies of the
> same program...

How so?  This presumes that the act of recording itself is resource 
intensive--it's not, since generally these days it's just dumping a 
low-bitrate stream to disk.  And since that Live TV recording will 
automatically be expired from disk (preferentially--over any other 
recordings) to make room for new recordings/Live TV, it's really just 
temporarily using (abundant) resources that otherwise would be idle.  
IMHO, the only wasteful part is the use of a tuner such that MythTV 
can't plan for most-efficient allocation of recording.  The limited 
resource here is the physical tuner.

>   additionally, it can potentially free that tuner for use in
> the event that the system needs it (with appropriate prompting to the user,
> as livetv does now).

But the user should /tell/ MythTV that he's foregoing Live TV control of 
the tuner so that MythTV can plan for most efficient allocation of 
tuners.  You say it can ask when it needs the tuner, but when does it 
need the tuner?  If a one-hour recording starts in 10mins and there's 
another tuner free, then I presume you want MythTV to use that other 
tuner instead of the one that's already reserved just in case the guy 
who's watching a recording decides to channel surf or something.  But, 
by using that tuner to record the upcoming recording, MythTV is making 
that tuner unavailable for future recordings.  Which means that when the 
next recording starts a half hour after the first recording, but it's on 
a Video Source that can't be recorded using the reserved tuner, the user 
has a conflict from MythTV's inefficiently allocating tuner usage.

But, if MythTV just schedules as if all tuners are available, but tries 
to keep one free for that user's "just in case" the Live TV user could 
end up with only a low-quality tuner because the one he was using was 
high quality (digital tuner) and the last one to be scheduled was low 
quality (PVR-x50 on a DTA) or similar.  Or the user may end up in a 
situation where the Live TV tuner he was using--a tuner that can record 
the channel he now wants to watch--was already allocated to a recording 
that the user would have told MythTV to not record so he can keep 
watching Live TV.  And, when you throw in multiple users with multiple 
"reserved" tuners, then you get to an issue of prioritization and it all 
gets /much/ more complex.

And please don't say, "Well, MythTV should know that it needs to use the 
reserved tuner to prevent a conflict from occurring later," (because 
I'll then add 3rd and 4th and ... recordings to show the problem is much 
more complex than anyone who hasn't tried to solve it likely realizes).  
Of course, if you've found a simple/inexpensive way of solving the 
traveling salesman problem, perhaps you could code it up so that MythTV 
can check every possible combination of scheduling, accounting for using 
the reserved tuner at any point and for any recording.

A far simpler solution (IMHO, the only reasonable solution, all things 
considered) is to just ask the user to relinquish control of the tuner 
if she /really/ wants to watch the already-recorded version.  Then, 
everyone knows the plan, MythTV can again schedule tuner allocation 
efficiently, and no one is surprised at the results.

>>> Or more importantly, why should a user /Care/ about tuners?  When they
>>> hit Watch TV, it should just work and let them view either of the
>>> currently recording programmes, or something else from those mux.  There
>>> shouldn't really be a need to tell the user that a tuner isn't available.
>>>
>> That's exactly how it works now (in 0.25+), with the exception of
>> informing them of/letting them easily switch to recorded episodes.  (Note
>> that you /can/ switch to recorded episodes through the OSD Menu, but with
>> current MythTV you would have to know to do that.)
>>
>> Users are never told that tuners aren't available.  They're only told if a
>> channel they're trying to tune isn't available (and only if it's not
>> possible to tune it anywhere).
>
> I think I would much rather tear up the livetv one-tuner-per-user
> contract... with the way that myth will now happily switch between tuners,
> the contract has already been broken anyway.
>
> Users should care about tuners... they are the key to this whole system and
> the user should be aware that the system can only record a limited number
> of things at a time.  If I try to tune to a channel that is unavailable, I
> would rather get a message saying "no available tuner can tune the selected
> channel"... its far less confusing then your channel not changing at all.
>
> When watching livetv, you should in reality be jumping from one in progress
> recording to another... if you select a show that is not being recorded, a
> new recording rule (with appropriate priority) is created that says "record
> any show on this channel until I say stop" and lets the system select any
> tuner it wants to meet that rule. (could even shuffle the tuners during
> show transitions if it wants). If the same channel appears in multiple
> sources, it should switch sources based on priorities... for example, I
> have two QAM tuners with 3 virtual channels each, and a Prime with only 3
> tuners (no virtual).  I would much rather my system use the QAM tuners
> whenever a channel is available there and leave the Prime free for those
> channels that only it is capable of tuning.
>
> The only other limitation that livetv should place on the system is that if
> mythtv tries to use the last remaining tuner capable of tuning the channel
> you are *currently watching*; you should be prompted that the system would
> like to "interrupt recording of this channel to support the recording of
> XXXX" and provide you the option to allow it... it shouldn't dump you to
> the menu if the recording your watching still has time remaining.
>
> I suppose, like Mike, I feel that "live tv" shouldn't exist in it's current
> form... replace it with instant ondemand recording rules... leave the
> backend to manage the tuners because if mythtv does one thing well, it's
> optimizing its use of hardware.

I actually think Live TV in its current form is the only way Live TV can 
exist--anything else isn't Live TV.

I do think it's useful to make it easier for users to find that there's 
something already recorded that allows them to free the tuner they're 
wasting on Live TV and watch the recording.

Oh, and as you see, there are already disagreements about what the 
definition of "The Right Thing" is, which makes it really hard to make 
MythTV just "Do The Right Thing" without involving the user--the /only/ 
player involved in the process who really knows what the right thing 
is.  If the user wants to watch the recording, now, the right thing is 
to give up the tuner.  If they want to keep channel surfing in case they 
stumble upon something useful, the right thing is to keep that tuner for 
their Live TV use.

(So, I think Live TV should continue to exist in its current form.  I 
just don't think any user should ever actually use it--nor should they 
want to, once they learn how much better life can be without Live TV. :)

Mike