[FFmpeg-user] Region of interest in ISOBMFF?

[Andrew Randrianasulu]

чт, 8 авг. 2024 г., 21:34 Bruce Gavin via ffmpeg-user <
ffmpeg-user at ffmpeg.org>:

>  Thanks for the great tip.
> Much appreciated.
> If this works, it is exactly what I am searching for.
>
> I'm having an invalid argument error.
> Please take a peek at the command line below, see if you can spot where I
> went wrong.
> My screen resolution is 3840:2160.
>
> ffmpeg -y -hide_banner -i 20000_LEAGUES_SPECIAL_PASSTHROUGH.mkv -c:v copy
> -c:a copy -c:s copy 20000_LEAGUES_SPECIAL_PASSTHROUGH.PAD.mkv
> -filter:pad=3840:2160:max(0\,(3840-iw)/2):max(0\,(2160-ih)/2


may be add ')' at very end so it will be two curly brackets opening, two
closing for max() equation ?


>
>
>
>     On Thursday, August 8, 2024 at 10:16:21 AM PDT, David Clemenceau <
> david.clemenceau at ubikamedia.com> wrote:
>
>  Hi Bruce,
>
> It should work with the following filter:
>
> pad=4096:2160:max(0\,(4096-iw)/2):max(0\,(2160-ih)/2
>
> (replace by 3840:2160 if you’re talking about UHD).
>
> David
>
> > Le 8 août 2024 à 17:58, Bruce Gavin via ffmpeg-user <
> ffmpeg-user at ffmpeg.org> a écrit :
> >
> > I have an interest in this as well.
> > I would like to embed a 480p video frame into the center of a black 4k
> video frame.
> > The intent is presenting 4k to a 4k TV set and avoid upscaling.
> >
> > Most TV do a terrible job of upscaling low res 480P, either DVD or over
> the air.
> > This would present a small image in the center of the 4k screen, but
> without the upscaling degradation of quality.
> >
> > Q:  is this possible, theory or practice?
> >
> >    On Thursday, August 8, 2024 at 04:17:38 AM PDT, Phil Rhodes via
> ffmpeg-user <ffmpeg-user at ffmpeg.org> wrote:
> >
> > Hello
> > This is not directly an ffmpeg question, but this seemed like a
> reasonable place to ask.
> > Is there any common approach to encoding a region of interest - that is,
> a rectangular area of the frame - as metadata into an ISOBMFF, that is,
> essentially a QuickTime or MP4 movie file?
> > I'm aware that some approaches to this have been invented for various
> applications, but not if there is any widely-recognised standard for it.
> > P
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