[mythtv] Patch to autodetect 4:3 Zoom aspect ratio

[Petr Stehlik]

Mårten Bohlin wrote:
>>  This is very cool. Though the zoom modes changed a bit in 0.21 but that
>>  will make it even easier probably. Great would be to extend this to
>>  detect also black bars on left and right sides for automatic half and
>>  full zoom on 16:9 displays :-)
> 
> I am not sure what you mean. My code solves the problem for people
> that have 16:9 displays and watch movies that has the 16:9 aspect
> ratio, but are broadcasted in 4:3. So I guess this is what you want to
> do?

I have a 16:9 display but most movies are broadcasted in 4:3 (with 
correct aspect ratio, I never seen a movie with incorrect aspect ratio) 
so they are pillarboxed. A good compromise for pillarbox on 16:9 display 
is "half zoom" AKA 14:9 zoom that maintains the aspect ratio and removes 
part of the black bars. The 14:9 zoom could be enabled automagically if 
the left&right side black bars were detected...

Actually it should be detected by checking the source aspect ratio, not 
by checking the black bars, sorry (as the black bars are not really 
there in the source material). I tried to add such code there but for 
some reason it works for live TV only, not for recordings..

But sometimes 16:9 movie is broadcasted in 4:3 (still with correct 
aspect ratio) by adding top&bottom black bars (letterbox) so on 16:9 
display it is then windowboxed. The code for detecting black bars could 
see this and enable full zoom to get rid of the black bars entirely.

Petr