[FFmpeg-trac] #9884(avcodec:open): CRF affects the number of produced frames in VP9

[FFmpeg]

#9884: CRF affects the number of produced frames in VP9
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             Reporter:  Athari      |                    Owner:  (none)
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:              |               Blocked By:
             Blocking:              |  Reproduced by developer:  1
Analyzed by developer:  1           |
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Changes (by James):

 * analyzed:  0 => 1
 * version:  unspecified => git-master
 * component:  undetermined => avcodec
 * reproduced:  0 => 1

Comment:

 This happens only when you try to encode a stream with an alpha channel.
 The alpha channel is encoded as a separate stream, and our wrapper is not
 handling it right.
 If you don't care about retaining that from your input images, a
 workaround is to force a pixel format without alpha, using -pix_fmt
 yuv420p or similar.
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Ticket URL: <https://trac.ffmpeg.org/ticket/9884#comment:4>
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