[FFmpeg-trac] #11610(swscale:new): scale with reference prevents video to be scaled with a second scale filter instance

[FFmpeg]

#11610: scale with reference prevents video to be scaled with a second scale filter
instance
-------------------------------------+-------------------------------------
             Reporter:  Alexander    |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  swscale      |                  Version:  7.1
             Keywords:  scale        |               Blocked By:
  scale2ref                          |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 == Summary of the bug:

 A user needs to overlay a logo which is scaled using a reference video as
 input. The reference video should be also scaled in the same command.

 **Result:** Scale filter fails to scale a video that is used as input for
 the reference.

 **Tests:** Logo scaled without reference video does not prevent video to
 be scaled (the video is scaled, logo scaled, logo overlayed).

 == How to reproduce:
 {{{
 % ffmpeg -y -t 10 -i 'input.mp4' -loop 1 -t 13 -i logo.png -filter_complex
 "\
 \
  [0:v]scale=-2:720[prepaired]; \
  [1:v][prepaired]scale=-1:rw/8[logo_scaled]; \
  [prepaired][logo_scaled]overlay=10:10" -c:v libx264 -preset fast
 output.mp4

 ffmpeg version N-119657-gf1b3e51950 [2025-05-22] [7.1.git]

 built with gcc 12 (Debian 12.2.0-14+deb12u1)
 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11610>
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