"Quality-based encoding not supported, please specify a bitrate and VBR setting."

[sebix]

I get this output on the command line:

> green-recorder 
/bin/sh: xdpyinfo: command not found
You are recording on: x11
/home/ele/Videos/.mkv
ffmpeg version 4.0.2 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 8 (SUSE Linux)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --incdir=/usr/include/ffmpeg --extra-cflags='-O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -g' --optflags='-O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -g' --disable-htmlpages --enable-pic --disable-stripping --enable-shared --disable-static --enable-gpl --disable-openssl --enable-avresample --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libcelt --enable-libcdio --enable-libcodec2 --enable-libdc1394 --enable-libdrm --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libssh --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libv4l2 --enable-libvpx --enable-libwebp --enable-libxml2 --enable-libzimg --enable-libzmq --enable-libzvbi --enable-lv2 --enable-vaapi --enable-vdpau --enable-libfdk_aac --enable-nonfree --enable-libx264 --enable-libx265 --enable-librtmp --enable-libxvid
  libavutil      56. 14.100 / 56. 14.100
  libavcodec     58. 18.100 / 58. 18.100
  libavformat    58. 12.100 / 58. 12.100
  libavdevice    58.  3.100 / 58.  3.100
  libavfilter     7. 16.100 /  7. 16.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  1.100 /  5.  1.100
  libswresample   3.  1.100 /  3.  1.100
  libpostproc    55.  1.100 / 55.  1.100
Input #0, x11grab, from ':0.0+785,534':
  Duration: N/A, start: 1542829543.035028, bitrate: N/A
    Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 363x299, 30 fps, 1000k tbr, 1000k tbn, 1000k tbc
Guessed Channel Layout for Input Stream #1.0 : stereo
Input #1, pulse, from 'default':
  Duration: N/A, start: 1542829543.447291, bitrate: 1536 kb/s
    Stream #1:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> vp9 (libvpx-vp9))
  Stream #1:0 -> #0:1 (pcm_s16le (native) -> opus (libopus))
Press [q] to stop, [?] for help
[x11grab @ 0x55baea09dd80] Thread message queue blocking; consider raising the thread_queue_size option (current value: 8)
[libvpx-vp9 @ 0x55baea0c6640] v1.7.0
[libopus @ 0x55baea0c8580] No bit rate set. Defaulting to 96000 bps.
[libopus @ 0x55baea0c8580] Quality-based encoding not supported, please specify a bitrate and VBR setting.
Error initializing output stream 0:1 -- Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height
Conversion failed!

I guess this line:

Quality-based encoding not supported, please specify a bitrate and VBR setting.

contains the actual error message. My ffmpeg is quite new (4.0.2), maybe the parameters changed somehow?

[mhsabbagh]

Probably some changes in the latest version of ffmpeg, dropping support for some options.

I have seen such things myself on bleeding-edge distributions. Sadly, this makes it harder for me to maintain the code so that it works on all distributions on all versions of ffmpeg. It takes more time and effort which I don't have at the moment.