[vlc-devel] Meaning of video zoom

Rémi Denis-Courmont remi at remlab.net
Fri May 25 10:08:37 CEST 2018


No - what matters in that instance is the code above that deals with A/R. I think it uses smallest sample dimension if size is not forced.

I wouldn't take that code as the holy grail though. It applies the zoom to forced dimensions, which is IMO a bug.

Le 25 mai 2018 10:20:34 GMT+03:00, Steve Lhomme <robux4 at ycbcr.xyz> a écrit :
>On 2018-05-24 9:04 PM, Rémi Denis-Courmont wrote:
>> 	Hello,
>>
>> If the SAR and PAR are equal, the meaning of zoom is clear: it is the
>ratio
>> from input samples to output pixels.
>>
>> But if they are not equal, according to what metric should the zoom
>be rated?
>> I can think of 5 different dimensions to measure it, and they are
>probably
>> others:
>> - diagonale,
>> - largest,
>> - smallest,
>> - horizontal or
>> - vertical.
>> (Not to mention reorientation.)
>>
>> I guess broadcasting industry reasons in vertical dimension, and
>display
>> industry in diagonales.
>
>The code does this:
>*width=*width*cfg->zoom.num/cfg->zoom.den;
>    *height=*height*cfg->zoom.num/cfg->zoom.den;
>
>So I suppose that's diagonale.
>
>
>
>>
>> N.B.: VLC has never measured the PAR to this point. Unless explicitly
>> configured (--monitor-par), it is assumed 1:1.
>>
>
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