[FFmpeg-user] "Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)" error

[Mohammed Bey Ahmed Khernache]

Hello,
I am facing an error when trying to decode HEVC-coded content for some
video sequences.
I varied the video resolution as follows:
2160p: decoded successfully
1600p:  decoded successfully
1080p: error
720p: error

When I try to decode low resolutions (720p and 1080p), ffmpeg outputs the
following error message: "Output file is empty, nothing was encoded (check
-ss / -t / -frames parameters if used)"

Below are the command line and the output.
-------------------------------------------------------------------------------
root at linaro-developer:~# ffmpeg -vcodec hevc_v4l2m2m -i
vary_resolution/kimono/AMP_D_Hisilicon_3_1080p_fps_25.265 -f null out.null
ffmpeg version 4.3 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-nonfree --enable-static
--disable-shared --enable-pthreads --enable-neon --enable-thumb
--enable-optimizations --enable-libv4l2
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, hevc, from
'vary_resolution/kimono/AMP_D_Hisilicon_3_1080p_fps_25.265':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: hevc (Main), yuv420p(tv), 1920x1080, 25 fps, 25
tbr, 1200k tbn, 25 tbc
[hevc_v4l2m2m @ 0xaaaae2112410] Using device /dev/video0
[hevc_v4l2m2m @ 0xaaaae2112410] driver 'qcom-venus' on card 'Qualcomm Venus
video decoder' in mplane mode
[hevc_v4l2m2m @ 0xaaaae2112410] requesting formats: output=HEVC capture=NV12
Stream mapping:
  Stream #0:0 -> #0:0 (hevc (hevc_v4l2m2m) -> wrapped_avframe (native))
Press [q] to stop, [?] for help
[hevc_v4l2m2m @ 0xaaaae2112410] VIDIOC_G_FMT ioctl
    Last message repeated 99 times
Output #0, null, to 'out.null':
  Metadata:
    encoder         : Lavf58.45.100
    Stream #0:0: Video: wrapped_avframe, yuv420p, 1920x1080, q=2-31, 200
kb/s, 25 fps, 25 tbn, 25 tbc
    Metadata:
      encoder         : Lavc58.91.100 wrapped_avframe
frame=    0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=   0x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: unknown
Output file is empty, nothing was encoded (check -ss / -t / -frames
parameters if used)
-------------------------------------------------------------------------------

*Note*: when I drop the "-vcodec hevc_v4l2m2m" option, the decoding is done
successfully. But, that's not what I am lookign for. I need the hardware
acceleration.

Any help is welcome.

Best regards
Mohammed