[FFmpeg-user] Misson, impossible?, Prescaling, a, video...

[meino.cramer at gmx.de]

Carl Eugen Hoyos <cehoyos at ag.or.at> [12-10-27 13:36]:
>  <meino.cramer <at> gmx.de> writes:
> 
> > When scaling to the size of the LCD screen of my embedded 
> > Linux board, which is 800x480 pixels, I either can do a 
> > 
> >  -vf scale=iw*sar:ih,scale=800:-1
> > 
> > or a 
> > 
> >  -vf scale=iw*sar:ih,scale=-1:480
> 
> Does the last example in https://ffmpeg.org/ffmpeg.html#scale 
> help?
> 
> Carl Eugen
> 
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> 


Hi Carl,

not really -- or did not understand the expressions of the commandline
yet...

The commandline expression which comes near that what I am tryin to accomplish is

    # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
    scale='min(500\, iw*3/2):-1'


Depending on the size of the input it its either better to
adapt the width of the video to the size of the LCD screen and
calculate the height from the width in accordance to the aspect ratio
or adapt the height of the video to the size of the LCD screen and
calculate the width from the height in accordance to the aspect ratio.

This "if->then->else" aspect of my problem seems not to be emulateable
by one commandline expression...

But I am sure, the real problem is sitting right in front of my
monitor... ;)

So, how can I proofe myself wrong? ;))

Best regards,
mcc