[FFmpeg-trac] #10987(avutil:new): Blend video filter *_expr options don't handle store and load functions correctly.

[FFmpeg]

#10987: Blend video filter *_expr options don't handle store and load functions
correctly.
-------------------------------------+-------------------------------------
             Reporter:  Fallan       |                    Owner:  (none)
                 Type:  enhancement  |                   Status:  new
             Priority:  normal       |                Component:  avutil
              Version:  git-master   |               Resolution:
             Keywords:  "blend       |               Blocked By:
  filter" "store and load" st()      |
  ld()                               |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Comment (by Michael Koch):

 I can reproduce the problem.

 This does not work:
 ffmpeg -f lavfi -i color=red -f lavfi -i color=yellow -lavfi
 blend=all_expr='st(0,clip((Y/H-0.5)/0.2,0,1));A*ld(0)+B*(1.0-ld(0))' -t 5
 -y out.mp4

 But the same expression without ld() and st() does work:
 ffmpeg -f lavfi -i color=red -f lavfi -i color=yellow -lavfi
 blend=all_expr='A*clip((Y/H-0.5)/0.2,0,1)+B*(1.0-clip((Y/H-0.5)/0.2,0,1))'
 -t 5 -y out.mp4
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Ticket URL: <https://trac.ffmpeg.org/ticket/10987#comment:1>
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