[FFmpeg-trac] #7177(undetermined:closed): crash when using scale with dst_format on 10 bit HEVC source file

[FFmpeg]

#7177: crash when using scale with dst_format on 10 bit HEVC source file
-------------------------------------+-------------------------------------
             Reporter:  Rollinnn     |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:  libx264      |               Resolution:  invalid
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
-------------------------------------+-------------------------------------
Changes (by cehoyos):

 * keywords:   => libx264
 * status:  new => closed
 * resolution:   => invalid


Comment:

 Replying to [ticket:7177 Rollinnn]:
 > Summary of the bug: I was trying to convert from HEVC 10 bit to x264 8
 bit and found that with '''-vf
 "scale=1280:534:flags=lanczos:dst_format=yuv420p" -vcodec libx264 -crf 18
 -preset ultrafast''' ffmpeg crashes.
 > ffmpeg is static 32 bit windows build from Zeranoe.
 > I guess that using dst_format in such way can be wrong, but with some
 files it works aithout any warnings.

 Are you indicating that the following command line does not cause the
 crash?
 {{{
 $ ffmpeg -i "hevc10bit -dst_format yuv420p crash.mkv" -vf
 "scale=1280:534:flags=lanczos" -pix_fmt yuv420p -vcodec libx264 -f null -
 }}}

 > {{{
 > Assertion failed!
 >
 > Program: d:\ffmpeg.exe
 > File: ../src/x264-20180118-7d0ff22/encoder/slicetype.c, Line 1988
 >
 > Expression: cost >= 0
 >
 > This application has requested the Runtime to terminate it in an unusual
 way.
 > Please contact the application's support team for more information.
 > }}}
 This indicates that the bug cannot be fixed in FFmpeg.

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Ticket URL: <https://trac.ffmpeg.org/ticket/7177#comment:1>
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