[FFmpeg-trac] #9617(avfilter:new): v360: rounding or +-1 errors

[FFmpeg]

#9617: v360: rounding or +-1 errors
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             Reporter:  Michael Koch  |                    Owner:  (none)
                 Type:  defect        |                   Status:  new
             Priority:  normal        |                Component:  avfilter
              Version:  git-master    |               Resolution:
             Keywords:                |               Blocked By:
             Blocking:                |  Reproduced by developer:  0
Analyzed by developer:  0             |
--------------------------------------+------------------------------------
Description changed by Michael Koch:

Old description:

> I tested the v360 filter with all 36 combinations of these input/output
> formats: equirectangular, flat, fisheye, dfisheye, cylindrical and ball.
> The command lines are below.
>
> I found the following problems:
>
> eq2ball: in column y=0 there are 8 black pixels but 9 blue pixels, same
> problem in column y=179
> eq2fish: unsymmetric behaviour in x and y axes, pixel 0,37 is red but
> pixel 37,0 is black
> eq2dfish: the right circle has larger diameter than the left circle
>
> fish2eq: the vertical line in the center is between x=88 and x=89, it
> should be wetween x=89 and x=90
> fish2flat: that's clearly visible
> fish2ball: the vertical line in the center is between x=88 and x=89, it
> should be wetween x=89 and x=90, same problem also for the horizontal
> line
> fish2cyl: the vertical line in the center is between x=87 and x=88, it
> should be wetween x=89 and x=90
>
> dfish2eq: error at right edge
> dfish2dfish: unsymmetric behaviour in left circle
> dfish2cyl: error at 44,22 and right edege
> dfish2ball: that's clearly unsymmetric
>
> flat2eq: unsymmetric behaviour, compare rows y=15 and y=74
> flat2fish: unsymmetric behaviour, compare rows y=15 and y=74
> flat2dfish: unsymmetric behaviour, compare rows y=15 and y=74
> flat2cyl: unsymmetric behaviour, compare rows y=0 and y=44
> flat2ball: unsymmetric behaviour, compare row y=45 with row y=134, same
> problem also for columns x=45 and x=135
>
> cyl2ball: unsymmetric behaviour, pixel 81,43 is black but pixel 81,135 is
> magenta
> cyl2dfish: the right circle has larger diameter than the left circle
> cyl2fish: unsymmetric behaviour, pixel 77,29 is red but pixel 77,151 is
> black
>

> Here are the command lines for the test images and all 36 combinations:
>
> ffmpeg -f lavfi -i color=black:s=180x90 -lavfi
> geq=r='255*mod(trunc(4*X/W),2)':g='255*trunc(2*X/W)':b='255*trunc(2*Y/H)'
> -frames 1 -y test.png
> ffmpeg -i test.png -lavfi crop=90:90 -y test2.png
>
> ffmpeg -i test.png -lavfi v360=e:e:h_fov=360:v_fov=180:interp=near -y
> eq2eq.png
> ffmpeg -i test.png -lavfi
> v360=e:flat:h_fov=120:v_fov=120:interp=near -y eq2flat.png
> ffmpeg -i test.png -lavfi v360=e:fisheye:interp=near -y eq2fish.png
> ffmpeg -i test.png -lavfi v360=e:dfisheye:h_fov=180:v_fov=180:interp=near
> -y eq2dfish.png
> ffmpeg -i test.png -lavfi
> v360=e:cylindrical:h_fov=360:v_fov=120:interp=near -y eq2cyl.png
> ffmpeg -i test.png -lavfi v360=e:ball:h_fov=180:v_fov=180:interp=near -y
> eq2ball.png
>
> ffmpeg -i test.png -lavfi
> v360=flat:e:ih_fov=120:iv_fov=120:h_fov=360:v_fov=180:interp=near -y
> flat2eq.png
> ffmpeg -i test.png -lavfi
> v360=flat:flat:ih_fov=120:iv_fov=120:h_fov=120:v_fov=120:interp=near -y
> flat2flat.png
> ffmpeg -i test.png -lavfi
> v360=flat:fisheye:ih_fov=120:iv_fov=120:interp=near -y flat2fish.png
> ffmpeg -i test.png -lavfi
> v360=flat:dfisheye:ih_fov=120:iv_fov=120:interp=near -y flat2dfish.png
> ffmpeg -i test.png -lavfi
> v360=flat:cylindrical:ih_fov=120:iv_fov=120:h_fov=360:v_fov=120:interp=near
> -y flat2cyl.png
> ffmpeg -i test.png -lavfi
> v360=flat:ball:ih_fov=120:iv_fov=120:interp=near -y flat2ball.png
>
> ffmpeg -i test2.png -lavfi v360=fisheye:e:interp=near -y fish2eq.png
> ffmpeg -i test2.png -lavfi
> v360=fisheye:flat:h_fov=120:v_fov=120:interp=near -y fish2flat.png
> ffmpeg -i test2.png -lavfi v360=fisheye:fisheye:interp=near -y
> fish2fish.png
> ffmpeg -i test2.png -lavfi v360=fisheye:dfisheye:interp=near -y
> fish2dfish.png
> ffmpeg -i test2.png -lavfi
> v360=fisheye:cylindrical:h_fov=120:v_fov=120:interp=near -y fish2cyl.png
> ffmpeg -i test2.png -lavfi v360=fisheye:ball:interp=near -y fish2ball.png
>
> ffmpeg -i test.png -lavfi v360=dfisheye:e:interp=near -y dfish2eq.png
> ffmpeg -i test.png -lavfi
> v360=dfisheye:flat:h_fov=120:v_fov=120:interp=near -y dfish2flat.png
> ffmpeg -i test.png -lavfi v360=dfisheye:fisheye:interp=near -y
> dfish2fish.png
> ffmpeg -i test.png -lavfi v360=dfisheye:dfisheye:interp=near -y
> dfish2dfish.png
> ffmpeg -i test.png -lavfi
> v360=dfisheye:cylindrical:h_fov=360:v_fov=120:interp=near -y
> dfish2cyl.png
> ffmpeg -i test.png -lavfi v360=dfisheye:ball:interp=near -y
> dfish2ball.png
>
> ffmpeg -i test.png -lavfi
> v360=cylindrical:e:ih_fov=360:iv_fov=120:interp=near -y cyl2eq.png
> ffmpeg -i test.png -lavfi
> v360=cylindrical:flat:ih_fov=360:iv_fov=120:h_fov=120:v_fov=120:interp=near
> -y cyl2flat.png
> ffmpeg -i test.png -lavfi
> v360=cylindrical:fisheye:ih_fov=360:iv_fov=120:w=180:h=180:interp=near -y
> cyl2fish.png
> ffmpeg -i test.png -lavfi
> v360=cylindrical:dfisheye:ih_fov=360:iv_fov=120:w=180:h=90:interp=near -y
> cyl2dfish.png
> ffmpeg -i test.png -lavfi
> v360=cylindrical:cylindrical:ih_fov=360:iv_fov=120:h_fov=360:v_fov=120:interp=near
> -y cyl2cyl.png
> ffmpeg -i test.png -lavfi
> v360=cylindrical:ball:ih_fov=360:iv_fov=120:w=180:h=180:interp=near -y
> cyl2ball.png
>
> ffmpeg -i test2.png -lavfi v360=ball:e:interp=near -y ball2eq.png
> ffmpeg -i test2.png -lavfi v360=ball:flat:h_fov=120:v_fov=120:interp=near
> -y ball2flat.png
> ffmpeg -i test2.png -lavfi v360=ball:fisheye:interp=near -y ball2fish.png
> ffmpeg -i test2.png -lavfi v360=ball:dfisheye:interp=near -y
> ball2dfish.png
> ffmpeg -i test2.png -lavfi
> v360=ball:cylindrical:h_fov=360:v_fov=120:interp=near -y ball2cyl.png
> ffmpeg -i test2.png -lavfi v360=ball:ball:interp=near -y ball2ball.png

New description:

 I tested the v360 filter with all 36 combinations of these input/output
 formats: equirectangular, flat, fisheye, dfisheye, cylindrical and ball.
 The command lines are below.

 I found the following problems:

 eq2ball: in column y=0 there are 8 black pixels but 9 blue pixels, same
 problem in column y=179
 eq2fish: unsymmetric behaviour in x and y axes, pixel 0,37 is red but
 pixel 37,0 is black
 eq2dfish: the right circle has larger diameter than the left circle

 fish2eq: the vertical line in the center is between x=88 and x=89, it
 should be wetween x=89 and x=90
 fish2flat: that's clearly visible
 fish2ball: the vertical line in the center is between x=88 and x=89, it
 should be wetween x=89 and x=90, same problem also for the horizontal line
 fish2cyl: the vertical line in the center is between x=87 and x=88, it
 should be wetween x=89 and x=90

 dfish2eq: error at right edge
 dfish2dfish: unsymmetric behaviour in left circle, vertical line is
 between x=43 and x=44, but it should be between x=44 and x=45
 dfish2cyl: error at 44,22 and right edege
 dfish2ball: that's clearly unsymmetric

 flat2eq: unsymmetric behaviour, compare rows y=15 and y=74
 flat2fish: unsymmetric behaviour, compare rows y=15 and y=74
 flat2dfish: unsymmetric behaviour, compare rows y=15 and y=74
 flat2cyl: unsymmetric behaviour, compare rows y=0 and y=44
 flat2ball: unsymmetric behaviour, compare row y=45 with row y=134, same
 problem also for columns x=45 and x=135

 cyl2ball: unsymmetric behaviour, pixel 81,43 is black but pixel 81,135 is
 magenta
 cyl2dfish: the right circle has larger diameter than the left circle
 cyl2fish: unsymmetric behaviour, pixel 77,29 is red but pixel 77,151 is
 black


 Here are the command lines for the test images and all 36 combinations:

 ffmpeg -f lavfi -i color=black:s=180x90 -lavfi
 geq=r='255*mod(trunc(4*X/W),2)':g='255*trunc(2*X/W)':b='255*trunc(2*Y/H)'
 -frames 1 -y test.png
 ffmpeg -i test.png -lavfi crop=90:90 -y test2.png

 ffmpeg -i test.png -lavfi v360=e:e:h_fov=360:v_fov=180:interp=near -y
 eq2eq.png
 ffmpeg -i test.png -lavfi
 v360=e:flat:h_fov=120:v_fov=120:interp=near -y eq2flat.png
 ffmpeg -i test.png -lavfi v360=e:fisheye:interp=near -y eq2fish.png
 ffmpeg -i test.png -lavfi v360=e:dfisheye:h_fov=180:v_fov=180:interp=near
 -y eq2dfish.png
 ffmpeg -i test.png -lavfi
 v360=e:cylindrical:h_fov=360:v_fov=120:interp=near -y eq2cyl.png
 ffmpeg -i test.png -lavfi v360=e:ball:h_fov=180:v_fov=180:interp=near -y
 eq2ball.png

 ffmpeg -i test.png -lavfi
 v360=flat:e:ih_fov=120:iv_fov=120:h_fov=360:v_fov=180:interp=near -y
 flat2eq.png
 ffmpeg -i test.png -lavfi
 v360=flat:flat:ih_fov=120:iv_fov=120:h_fov=120:v_fov=120:interp=near -y
 flat2flat.png
 ffmpeg -i test.png -lavfi
 v360=flat:fisheye:ih_fov=120:iv_fov=120:interp=near -y flat2fish.png
 ffmpeg -i test.png -lavfi
 v360=flat:dfisheye:ih_fov=120:iv_fov=120:interp=near -y flat2dfish.png
 ffmpeg -i test.png -lavfi
 v360=flat:cylindrical:ih_fov=120:iv_fov=120:h_fov=360:v_fov=120:interp=near
 -y flat2cyl.png
 ffmpeg -i test.png -lavfi v360=flat:ball:ih_fov=120:iv_fov=120:interp=near
 -y flat2ball.png

 ffmpeg -i test2.png -lavfi v360=fisheye:e:interp=near -y fish2eq.png
 ffmpeg -i test2.png -lavfi
 v360=fisheye:flat:h_fov=120:v_fov=120:interp=near -y fish2flat.png
 ffmpeg -i test2.png -lavfi v360=fisheye:fisheye:interp=near -y
 fish2fish.png
 ffmpeg -i test2.png -lavfi v360=fisheye:dfisheye:interp=near -y
 fish2dfish.png
 ffmpeg -i test2.png -lavfi
 v360=fisheye:cylindrical:h_fov=120:v_fov=120:interp=near -y fish2cyl.png
 ffmpeg -i test2.png -lavfi v360=fisheye:ball:interp=near -y fish2ball.png

 ffmpeg -i test.png -lavfi v360=dfisheye:e:interp=near -y dfish2eq.png
 ffmpeg -i test.png -lavfi
 v360=dfisheye:flat:h_fov=120:v_fov=120:interp=near -y dfish2flat.png
 ffmpeg -i test.png -lavfi v360=dfisheye:fisheye:interp=near -y
 dfish2fish.png
 ffmpeg -i test.png -lavfi v360=dfisheye:dfisheye:interp=near -y
 dfish2dfish.png
 ffmpeg -i test.png -lavfi
 v360=dfisheye:cylindrical:h_fov=360:v_fov=120:interp=near -y dfish2cyl.png
 ffmpeg -i test.png -lavfi v360=dfisheye:ball:interp=near -y dfish2ball.png

 ffmpeg -i test.png -lavfi
 v360=cylindrical:e:ih_fov=360:iv_fov=120:interp=near -y cyl2eq.png
 ffmpeg -i test.png -lavfi
 v360=cylindrical:flat:ih_fov=360:iv_fov=120:h_fov=120:v_fov=120:interp=near
 -y cyl2flat.png
 ffmpeg -i test.png -lavfi
 v360=cylindrical:fisheye:ih_fov=360:iv_fov=120:w=180:h=180:interp=near -y
 cyl2fish.png
 ffmpeg -i test.png -lavfi
 v360=cylindrical:dfisheye:ih_fov=360:iv_fov=120:w=180:h=90:interp=near -y
 cyl2dfish.png
 ffmpeg -i test.png -lavfi
 v360=cylindrical:cylindrical:ih_fov=360:iv_fov=120:h_fov=360:v_fov=120:interp=near
 -y cyl2cyl.png
 ffmpeg -i test.png -lavfi
 v360=cylindrical:ball:ih_fov=360:iv_fov=120:w=180:h=180:interp=near -y
 cyl2ball.png

 ffmpeg -i test2.png -lavfi v360=ball:e:interp=near -y ball2eq.png
 ffmpeg -i test2.png -lavfi v360=ball:flat:h_fov=120:v_fov=120:interp=near
 -y ball2flat.png
 ffmpeg -i test2.png -lavfi v360=ball:fisheye:interp=near -y ball2fish.png
 ffmpeg -i test2.png -lavfi v360=ball:dfisheye:interp=near -y
 ball2dfish.png
 ffmpeg -i test2.png -lavfi
 v360=ball:cylindrical:h_fov=360:v_fov=120:interp=near -y ball2cyl.png
 ffmpeg -i test2.png -lavfi v360=ball:ball:interp=near -y ball2ball.png

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Ticket URL: <https://trac.ffmpeg.org/ticket/9617#comment:2>
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