[FFmpeg-trac] #7818(avfilter:closed): crop filter can't do single pixel width

FFmpeg trac at avcodec.org
Thu Mar 28 19:47:52 EET 2019


#7818: crop filter can't do single pixel width
-------------------------------------+------------------------------------
             Reporter:  adaerr       |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  minor        |                Component:  avfilter
              Version:  git-master   |               Resolution:  invalid
             Keywords:  crop filter  |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+------------------------------------
Changes (by Gyan):

 * priority:  normal => minor
 * resolution:   => invalid
 * status:  new => closed
 * component:  ffmpeg => avfilter


Comment:

 The crop filter, by default, constrains output dimensions, taking into
 account the chroma subsampling scheme of the input. For the common 4:2:0
 format, each dimension needs to be even, so, crop will round down odd
 values. For the case of width 1, that's rounded to 0, which is, of course,
 invalid. Your input is probably 4:2:2, for which there is no constraint on
 values for height.

 To override this behaviour, set option exact to 1 i.e.

 `-vf "crop=1:70:exact=1"`

 Although you'll get an error from encoders like x264 which require even
 dimensions for 4:2:0 input. JPEG output should be fine.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7818#comment:1>
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