[FFmpeg-trac] #9332(undetermined:new): Flickering white when using scale and zoompan

[FFmpeg]

#9332: Flickering white when using scale and zoompan
-------------------------------------+-------------------------------------
             Reporter:  mucikiki     |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  unspecified  |               Resolution:
             Keywords:  zoompan      |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Description changed by mucikiki:

Old description:

> Summary of the bug:
> When I try to zoom an image, if this image has a white background
> (255,255,255) I obtain an output with a variable white (between
> 255,255,255 and 255,254,255). It is ok with other colors.
>
> How to reproduce:
> {{{
> % ffmpeg -f image2 -loop 1 -t 6.2 -r 29.97 -i xxxx -c:v libx264
> -profile:v main -pix_fmt yuv420p -level:v 3.1 -crf 24 -color_primaries
> bt709 -color_trc bt709 -colorspace bt709 -y -filter_complex
> "[0:v]scale=12800x7200,zoompan=z='min(zoom+0.0015,1.5)':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':d=184:fps=29.97:s=1280x720,trim=duration=6.2[filtered]"
> ffmpeg version N-48944-g9b069eb14e-static
> https://johnvansickle.com/ffmpeg/
> built on gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
> }}}
>
> I can't upload my example, you can see here:
> https://www.dropbox.com/s/728fuvdhc2a4gql/esempio%20tremolio%20per%20sito%20ffmpeg.mp4?dl=0

New description:

 Summary of the bug:
 When I try to zoom an image, if this image has a white background
 (255,255,255) I obtain an output with a variable white (between
 255,255,255 and 255,254,255). It is ok with other colors.

 IMPORTANT: this only happens with big scale number, for example
 scale=12800x7200. It is ok with scale=1280x720.

 How to reproduce:
 {{{
 % ffmpeg -f image2 -loop 1 -t 6.2 -r 29.97 -i xxxx -c:v libx264 -profile:v
 main -pix_fmt yuv420p -level:v 3.1 -crf 24 -color_primaries bt709
 -color_trc bt709 -colorspace bt709 -y -filter_complex
 "[0:v]scale=12800x7200,zoompan=z='min(zoom+0.0015,1.5)':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':d=184:fps=29.97:s=1280x720,trim=duration=6.2[filtered]"
 ffmpeg version N-48944-g9b069eb14e-static
 https://johnvansickle.com/ffmpeg/
 built on gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
 }}}

 Input file:
 https://www.dropbox.com/s/j50lf6we1c6ouvu/esempio%20tremolio%20per%20sito%20ffmpeg.jpg?dl=0
 Output video:
 https://www.dropbox.com/s/728fuvdhc2a4gql/esempio%20tremolio%20per%20sito%20ffmpeg.mp4?dl=0

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Ticket URL: <https://trac.ffmpeg.org/ticket/9332#comment:3>
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