Unable to use mjpeg_cuvid hardware accelerated decoding

[Andrew Udvare]

Summary of the bug:
When I use ffmpeg -hwaccel cuvid -c:v mjpeg_cuvid ..., I get a strange error regarding filters when no filters are set.

My car dashcam records in this format, and produces up to 3 minute files that I merge together (they are grouped by day). The same error occurs if I use the concat filter.

How to reproduce:

 $ for i in encoders decoders filters; do echo $i:; ffmpeg -hide_banner -${i} | egrep -i "npp|cuvid|nvenc|cuda"; done
encoders:
 V..... h264_nvenc           NVIDIA NVENC H.264 encoder (codec h264)
 V..... nvenc                NVIDIA NVENC H.264 encoder (codec h264)
 V..... nvenc_h264           NVIDIA NVENC H.264 encoder (codec h264)
 V..... nvenc_hevc           NVIDIA NVENC hevc encoder (codec hevc)
 V..... hevc_nvenc           NVIDIA NVENC hevc encoder (codec hevc)
decoders:
 V..... h264_cuvid           Nvidia CUVID H264 decoder (codec h264)
 V..... hevc_cuvid           Nvidia CUVID HEVC decoder (codec hevc)
 V..... mjpeg_cuvid          Nvidia CUVID MJPEG decoder (codec mjpeg)
 V..... mpeg1_cuvid          Nvidia CUVID MPEG1VIDEO decoder (codec mpeg1video)
 V..... mpeg2_cuvid          Nvidia CUVID MPEG2VIDEO decoder (codec mpeg2video)
 V..... mpeg4_cuvid          Nvidia CUVID MPEG4 decoder (codec mpeg4)
 V..... vc1_cuvid            Nvidia CUVID VC1 decoder (codec vc1)
 V..... vp8_cuvid            Nvidia CUVID VP8 decoder (codec vp8)
 V..... vp9_cuvid            Nvidia CUVID VP9 decoder (codec vp9)
filters:
 ... hwupload_cuda     V->V       Upload a system memory frame to a CUDA device.

 $ ffmpeg -hwaccel cuvid -c:v mjpeg_cuvid -i src/10370426/15430025.AVI out.mp4                                                                               
ffmpeg version 3.3 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.0 (Gentoo 5.4.0-r3 p1.3, pie-0.6.5)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --docdir=/usr/share/doc/ffmpeg-3.3/html --mandir=/usr/share/man --enable-shared --cc=x86_64-pc-linux-gnu-gcc --cxx=x86_64-pc-linux-gnu-g++ --ar=x86_64-pc-linux-gnu-ar --optflags='-O2 -pipe -march=native -fomit-frame-pointer -ggdb' --disable-
static --enable-avfilter --enable-avresample --disable-stripping --enable-nonfree --enable-version3 --disable-indev=oss --disable-indev=jack --disable-outdev=oss --enable-version3 --enable-nonfree --enable-bzlib --disable-runtime-cpudetect --disable-debug --disable-gcrypt --disable-gnutls --disable-gmp --enable-g
pl --enable-hardcoded-tables --enable-iconv --disable-lzma --enable-network --enable-openssl --enable-postproc --enable-libsmbclient --enable-ffplay --enable-sdl2 --disable-vaapi --enable-vdpau --enable-xlib --enable-libxcb --enable-libxcb-shm --enable-libxcb-xfixes --enable-zlib --enable-libcdio --enable-libiec6
1883 --disable-libdc1394 --enable-libcaca --disable-openal --enable-opengl --disable-libv4l2 --disable-libpulse --enable-libopencore-amrwb --enable-libopenco
re-amrnb --enable-libfdk-aac --enable-libopenjpeg --enable-libbluray --disable-libcelt --enable-libgme --enable-libgsm --disable-mmal --enable-libmodplug --e
nable-libopus --disable-libilbc --enable-librtmp --enable-libssh --enable-libschroedinger --enable-libspeex --enable-libvorbis --enable-libvpx --enable-libzv
bi --disable-libbs2b --enable-chromaprint --enable-libflite --disable-frei0r --enable-libfribidi --disable-fontconfig --disable-ladspa --enable-libass --enab
le-libfreetype --enable-librubberband --disable-netcdf --disable-libzmq --enable-libzimg --disable-libsoxr --enable-pthreads --disable-libvo-amrwbenc --enabl
e-libmp3lame --disable-libkvazaar --enable-nvenc --disable-libopenh264 --disable-libsnappy --enable-libtheora --enable-libtwolame --enable-libwavpack --enabl
e-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --disable-amd3dnow --disable-amd3dnowext --disable-fma4 --disable-xop --cpu=host --disable-doc -
-disable-htmlpages --enable-manpages
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[avi @ 0x22635e0] sample size (1) != block align (2)
Guessed Channel Layout for Input Stream #0.1 : mono
Input #0, avi, from 'src/10370426/15430025.AVI':
  Duration: 00:03:02.00, start: 0.000000, bitrate: 24610 kb/s
    Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj420p(pc, bt470bg/unknown/unknown), 1920x1080, 23105 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 32000 Hz, mono, s16, 512 kb/s
File 'out.mp4' already exists. Overwrite ? [y/N] y
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg (mjpeg_cuvid) -> h264 (libx264))
  Stream #0:1 -> #0:1 (pcm_s16le (native) -> aac (native))
Press [q] to stop, [?] for help
[mjpeg_cuvid @ 0x2267da0] ignoring invalid SAR: 0/0
Impossible to convert between the formats supported by the filter 'Parsed_null_0' and the filter 'auto_scaler_0'
Error reinitializing filters!
Failed to inject frame into filter network: Function not implemented
Error while processing the decoded data for stream #0:0
Conversion failed!

[Timo R.]

Use a cuda aware encoder, or drop the hwaccel flag.
Not a bug.