[mythtv] [PATCH] OSD glitch - starts as 4:3 and corrects to 16:9

Matt Doran matt.doran at papercut.biz
Fri May 25 01:16:51 UTC 2007

Matthew Wire wrote:
> On Fri, 2007-05-25 at 08:21 +1000, Matt Doran wrote:
>> Daniel Kristjansson wrote:
>>> On Thu, 2007-05-24 at 23:45 +1000, Matt Doran wrote:
>>>> It wasn't the constructor.  It took me a while to figure out how the 
>>>> video playback process works ... but I got there eventually.  :)    In a 
>>>> method in NuppelVideoPlayer called OpenDummy which sets up the dummy 
>>>> video while waiting for the channel to tune....  it sets the video size 
>>>> arbitrarily to 720x576 and aspect of 1.3333.  At this point we don't 
>>>> have access to the display size.  We don't know that until in the 
>>>> InitVideo method.
>>>> So my fix was to set the force the video aspect to the display aspect if 
>>>> we're in dummy mode.  It works very nicely.  Now when I start to watch 
>>>> live tv, the OSD appears at the full width (16:9).  I don't get the 
>>>> ugliness of switching from the default 4:3 to 16:9 when the video starts.
>>>> The patch was only a couple of lines, and it results in much more 
>>>> polished results. :)   
>>>> What do you think?
>>> It looks like a decent enough hack. It will still chose the
>>> wrong video aspect ratio whenever you view a non-16:9 stream
>>> on a 16:9 screen, but at least it will default to filling the
>>> screen for 16:9 screens so it's an improvement. What I would
>>> like to see down the road is some intelligent guessing as to
>>> the aspect ratio. If we are about to view channel X and the
>>> last time we viewed it the resolution and aspect ratio were Y,
>>> then we should start with Y when we start on channel X. If we
>>> are using xrandr we really want to minimize these changes.
>>> Can you open a ticket with your hack?
>> Will do.
>> I realise it was a bit of a hack.  When the dummy video is setup we 
>> don't have access to the display dimentions, so had to adjust the aspect 
>> when we're initialising the video.
>> My theory was that it's no worse than we've got now.  It's also a hack 
>> to assume you have 4:3 display, so I figured we may as well use the 
>> aspect of the display as a best guess.   I'm in Australia, where all our 
>> DVB broadcasts are 16:9.  So this works nicely for me.
>> I realise it could be smarter, but it's a start.  ;)
> Maybe a better option would be to add a database setting for screen
> aspect ratio.  Would have to be a per-frontend setting but I can't
> imagine it changing very often once it's set.
I think it makes sense to default to the aspect ratio of the display. 

I guess it might make sense to have an override in the database to set 
the the default aspect.   But I don't know whether it would add much 
value?  Who would change it from the default (your display aspect ratio).

It might be better to have a setting for each channel that overrides the 
aspect ratio.  But remember, that this change only changes the aspect of 
the dummy video stream ... when the real video stream appears myth will 
set the aspect based on the stream itself.   This just makes the startup 
of live tv look more polished.

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