[FFmpeg-trac] #6971(ffmpeg:new): ffmpeg drops frames after deinterlacing

[FFmpeg]

#6971: ffmpeg drops frames after deinterlacing
-----------------------------------+----------------------------------
             Reporter:  CaryKnoop  |                     Type:  defect
               Status:  new        |                 Priority:  normal
            Component:  ffmpeg     |                  Version:  3.4
             Keywords:             |               Blocked By:
             Blocking:             |  Reproduced by developer:  0
Analyzed by developer:  0          |
-----------------------------------+----------------------------------
 Summary of the bug:

 NVIDIA's encoder supports deinterlacing. This optionally includes
 deinterlacing with frame doubling. In case frame doubling is wanted the
 NVIDIA decoder correctly doubles the frames, however ffmpeg does not pass
 this on to the encoder but instead drops all doubled frames.

 Regardless of the NVIDIA cuvid parameter settings -deint (1, 2) and
 -drop_second_field (0, 1) frames get dropped by ffmpeg.

 How to reproduce:
 {{{
 For full hardware decoding and encoding:
 % ffmpeg -hwaccel cuvid -c:v mpeg2_cuvid -deint 2 -drop_second_field 0 -i
 <interlaced mpeg-2 file> -c:v h264_nvenc -b:v 80M -profile:v high -preset
 slow <out file>

 Or for hardware decoding and encoding but passing the intermediate results
 to system buffers:
 % ffmpeg  -c:v mpeg2_cuvid -deint 2 -drop_second_field 0 -i <interlaced
 mpeg-2 file>  -c:v h264_nvenc -b:v 80M -profile:v high -preset slow <out
 file>

 ffmpeg version N-89825-g1b5d3c08e3 Copyright (c) 2000-2018 the FFmpeg
 developers
   built with gcc 7.2.0 (GCC)
   configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-
 bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass
 --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-
 libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
 --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr
 --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack
 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2
 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-
 libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa
 --enable-libspeex --enable-libmfx --enable-amf --enable-cuda --enable-
 cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth
   libavutil      56.  7.100 / 56.  7.100
   libavcodec     58.  9.100 / 58.  9.100
   libavformat    58.  5.100 / 58.  5.100
   libavdevice    58.  0.100 / 58.  0.100
   libavfilter     7. 11.101 /  7. 11.101
   libswscale      5.  0.101 /  5.  0.101
   libswresample   3.  0.101 /  3.  0.101
   libpostproc    55.  0.100 / 55.  0.100

 CUDA library: 9,1
 NVIDIA Driver: 388.19
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6971>
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