[FFmpeg-trac] #6755(avcodec:new): corrupt output and rate control issues when using vp9_vaapi encoder in CBR or VBR mode

[FFmpeg]

#6755: corrupt output and rate control issues when using vp9_vaapi encoder in CBR
or VBR mode
---------------------------------+--------------------------------------
             Reporter:  armena   |                     Type:  defect
               Status:  new      |                 Priority:  normal
            Component:  avcodec  |                  Version:  git-master
             Keywords:           |               Blocked By:
             Blocking:           |  Reproduced by developer:  0
Analyzed by developer:  0        |
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 Summary of the bug:

 When using the vp9_vaapi encoder in CBR or VBR mode, the output video may
 be corrupted. At a dissolve from a full-screen logo to video from a
 camera, the output became garbled for several seconds. Also, in VBR mode,
 the output bitrate is approximately 1/2 of the requested value.

 This was found using the i965 vaapi driver on an Intel Kabylake cpu. I
 attempted to reproduce using vp9enc (shipped with vaapi-utils) but was not
 able to do so, so my initial assumption is that this is an ffmpeg issue.
 I've been able to encode the same file successfully using other vaapi
 codecs (vp8, h264, hevc) with similar ffmpeg options.

 How to reproduce:
 {{{
 /usr/local/bin/ffmpeg -vaapi_device /dev/dri/renderD128 -i
 /var/www/html/rpitv_test/20170121_whockey_union_p0.mp4 -vf
 "format=nv12,hwupload,deinterlace_vaapi,scale_vaapi=w=1920:h=1080" -c:v
 vp9_vaapi -b:v 4400k -bufsize 17600k -maxrate 4400k -g 150 -keyint_min 150
 -bf 1 -bsf:v vp9_raw_reorder,vp9_superframe -an -f webm -dash 1 -r 29.97
 20170121_whockey_union_p0-v4400.webm
 ffmpeg version N-87873-g2e94490225 Copyright (c) 2000-2017 the FFmpeg
 developers
   built with gcc 6.3.0 (Debian 6.3.0-18) 20170516
   configuration: --enable-libvorbis --enable-libvpx --enable-vaapi
 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/6755>
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