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

[Marian Durkovic]

> 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.

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.

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----   Marian Durkovic                       network  manager         ----
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