[mythtv-users] Aspect ratio (16:9 anamorphic)

Richard Garnish rabies at meep.org
Thu May 5 17:50:09 UTC 2005


On Thu, 2005-05-05 at 18:40, Joseph A. Caputo wrote:
> On Thursday 05 May 2005 13:10, Michael Haan wrote:
> > On 5/5/05, James Stembridge <jstembridge at gmail.com> wrote:
> > > On 5/5/05, Doug Larrick <doug at ties.org> wrote:
> > > > But are your pixels square?  720x480 is pretty close to square 
> > > > pixels on 
> > > > a 16:9 set.
> > > 
> > > I wouldn't think so, I'm using 720x576 too. I'll have a closer look 
> > > tonight. 
> > > 
> > > James.
> > 
> > What do you mean by saying your pixels are square?  The text is blocky
> > in the UI?
> 
> He's referring to the actual shape of a pixel on a computer monitor vs. 
> a television.  Computer monitors have square (well, really circular) 
> pixels, while TVs have oblong (wider than tall) pixels.  So an image 
> that looks like a perfect square on a computer monitor will look 
> 'stretched' (i.e., rectangular) on a television.  I'm not sure if a HD 
> television has oblong or 'square' pixels.

Thankfully, true HD has square pixels :)  Do the maths to check:

4/3=1.3333, 16/9=1.7777

1280/720=1.7777
1920/1080=1.7777

So if you are driving a 16:9 display at 1280x720, it should display
everything in the right shape if the software assumes "square" pixels.

Just for comparison, the SD resolutions:
720/576=1.25 (differs from 4/3 by 6%)
720/486=1.4815 (differs in the other direction by 11%)

Richard



More information about the mythtv-users mailing list