[FFmpeg-trac] #458(swscale:new): Scale filter can create output which scale filter cannot accept on its input

[FFmpeg]

#458: Scale filter can create output which scale filter cannot accept on its
input
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               Reporter:  mdsh        |                  Owner:  michael
                   Type:  defect      |                 Status:  new
               Priority:  normal      |              Component:  swscale
                Version:  git-master  |               Keywords:
             Blocked By:              |               Blocking:
Reproduced by developer:  0           |  Analyzed by developer:  0
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 I know this is a bit of a bizarre filter chain, It's constructed to
 demonstrate the point I'm hoping to make, without using any of my code.

 Clock10.mov is just a PAL DV, but I think any _interlaced_ file will do.

 ./ffmpeg -loglevel debug -i ~/Movies/Clock10.mov -vf
 "slicify=32,scale=0:0:interl=1,format=yuv420p,scale=0:0:interl=1,format=yuv422p,scale=0:0:interl=1,format=yuv420p"
 -pix_fmt yuv420p -vframes 1 -an -f rawvideo -y /dev/null

 Essentially, the 'y' parameter in the slices of the output of the second
 scale is not aligned by 4 (the first slice is, in fact, 26 lines high,
 so the second slice starts at 26) so it is not valid for the input of
 the third scale.

 I don't think the output of this filter chain should throw an assert.

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/458>
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