[mythtv-users] Playback looks at screensize not at monitor or windowsize

[Hika van den Hoven]

Hoi Michael,

Friday, June 12, 2015, 8:58:25 AM, you wrote:

> On 06/11/2015 08:56 PM, Hika van den Hoven wrote:
>> Friday, June 12, 2015, 2:00:30 AM, you wrote:
>>
>>>   I recently got a new extra monitor for my workcomputer and was
>>>   experimenting with displaying mythtv on there. The configuration is
>>>   two monitors (1920x1080 and 1600x1200) in one screen (3520x1200)
>>>   I have tried both displaying mythtv in a full window on the new
>>>   screen and in a smaller one 1280x720. Everything goes ok until I try
>>>   playback, either live or recorded. I get a display with 16:9
>>>   stretched out to 3520:1200 or 44:15. It seems Mythtv looks at the
>>>   screen size and not at the monitor or window size.
>>>   I set up the windowsize in Screen Settings with "Use GUI size for TV
>>>   playback" checked. Above there I now can select which screen to
>>>   display on (0, 1 or All) but of cause they are all the same, the
>>>   monitors are organized in one screen. Also I can select an aspect
>>>   ratio (16:9, 16:10 and 4:3) bot not 44:15. It actually says there it
>>>   cannot query a xinerama display and I should specify it, which I can
>>>   understand. But I cannot, for the right values are missing.
>>>   Could  this field be split in two or to some running percentage, so
>>>   you can specify something? The three possibilities are nonsense for a
>>>   xinerama display, it will always be two or more monitors linked
>>>   together. Either that or it should look at the GUI setting for the
>>>   aspect ratio.
>>>    I can get a somewhat
>>>   decent display by falsely telling the 16:9 picture is 4:3.
>> I found the solution. I suddenly remembered you can adjust settings
>> through mythweb. I set XineramaMonitorAspectRatio to 2.933333
>> It now shows up like that in The Screen Setting. But you still can not
>> edit it there. It should be a free fill field.

> You should use the frontend settings editor to set the Appearance 
> settings properly, and you shouldn't ever insert disallowed values 
> directly into settings with MythWeb's 
> (dangerous/broken-because-it-allows-invalid-values) settings editor.  If
> you have any kind of Xinerama-type multi-monitor display (including 
> TwinView or what-have-you), you *must* set the 2 Appearance settings:

> Monitor aspect ratio
> The aspect ratio of a Xinerama display cannot be queried from the 
> display, so it must be specified.

> and:

> Display on screen
> Run on the specified screen or spanning all screens.

> and should not (ever--for anyone, even without Xinerama) set the 
> Playback setting:

> Video aspect override
> When enabled, these will override the aspect ratio specified by any 
> broadcaster for all video streams.

> where, if (for anyone at all) it seems like "Video aspect override" 
> needs to be set to get a proper display, you have misconfigured 
> something else (like, for example, your X configuration for 
> DPI/DisplaySize).

I fully agree with what you say above. Only Nvidia deals with
multi-monitor in a way impossible with other drivers and MythTV
doesn't seem able to deal with that. As said One X screen containing
both monitors. It is like Xinerama but actually incompatible with it.
MythTV is not the only one not understanding it. Most applications
that are aware of the two monitors are not properly able to
distinguish them. Window managers do full-screen to both and Vbox 
also sees two but cannot distinguish them. As said the selection of
"Display on Screen" does do nothing, because both monitors are on the
same X screen. It should either forget underlying hardware or look
deeper, which is possible.

> It seems you're saying you think you need to set "Monitor aspect ratio"
> to 44:15, but that's not right because neither of your monitors has a 
> 44:15 aspect--one is 16:9 and the other is 4:3 (assuming square pixels,
> which is almost definitely the case).  Since (I'm pretty sure) you're 
> going to be displaying the video on one or the other monitor (and don't
> want it stretched across both monitors with some funky stepped 
> letterboxing--not to mention an annoying bezel break in the picture), 
> you simply specify the aspect ratio of the monitor on which you're 
> displaying the video.

Won't work

> Since you seem to be saying that it doesn't work when you specify a 
> proper value for "Monitor aspect ratio", I can conclude that you have 
> some other (related) setting misconfigured.  For example, if you do not
> specify "Display on screen" (or specify it incorrectly), you may get 
> some strange behavior, possibly exactly what you're seeing.  Similarly,
> if your X configuration for DPI/DisplaySize (for /either/ monitor) is 
> incorrect or incorrectly calculated (if not specified), you'd get broken
> behavior, such as you're seeing.

It is all set correctly. Only MythTV and others expect two driver
instances and two X screens, one for each monitor. This is the only way
with a none Nvidia driver. The way Nvidia deals with it is actually
more logical, properly splitting between monitor and screen and really
creating one screen spanning both monitors.
MythTV tries to understand it but only comes halfway, while it should
be simple if, when set, it would only looks at the GUI size settings,
forgetting the underlying hardware.

> Mike
> _______________________________________________


Tot mails,
  Hika                            mailto:hikavdh at gmail.com

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