[vlc-devel] Re: [patch] Fixed source aspect ratio calculation

[Sigmund Augdal Helberg]

On Mon, 2005-10-17 at 16:55 +0200, Marian Durkovic wrote:
> > I have one issue here:
> > 
> > +        if( p_dec->fmt_out.video.i_visible_height == 1088 )
> > +        {
> > +            p_dec->fmt_out.video.i_visible_height = 1080;
> > +            msg_Warn( p_dec, "Incorrect HDTV stream - reducing  
> > height to 1080");
> > +        }
> > 
> > 
> > Now... what if i actually want to send a 1088 stream?
> > 
> > DJ
> 
> Then you're out of luck... Why would someone want to do that ? 
> 1088 does not fit into any common aspect ratio (4:3, 16:9)
> 
> HDTV norms strictly speak about 720 or 1080 lines but there are many
> broken MPEG2 encoders out there which don't set display height properly.
If the encoder doesn't set the display height properly then all these
consequences are in due order. But afaik vlc does still display the gray
line if the encoder does set this properly. So let's focus on findig a
real solution before resolving to these kinds of hacks.

Sigmund
> 
> 1088 not only causes the HDTV grey line bug, but it also terribly breaks 
> aspect ratio calculation, 1920:1080 = 16:9, but if you have 1088 here,
> after 16:9 aspect ratio adjustment you'll end up in screen dimensions 
> of 1934x1088.
> 
> That means your high quality input picture 1920x1080 with exactly square 
> pixels gets rescaled into 1934x1088 and the quality is gone.
> 
> Since this bug is very common (see e.g. HD-1 and HD-5 channels at Astra 1D)
> it's IMHO better to prefer standards-based HDTV format over possibility
> to support (almost unusable) 1088 height.
> 
> 
> 	With kind regards,
> 
> 		M.
> 
> --------------------------------------------------------------------------
> ----                                                                  ----
> ----   Marian Durkovic                       network  manager         ----
> ----                                                                  ----
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