[FFmpeg-trac] #9093(undetermined:new): log level debug causes command to work

[FFmpeg]

#9093: log level debug causes command to work
----------------------------------------+----------------------------------
             Reporter:  certaindestiny  |                     Type:  defect
               Status:  new             |                 Priority:  normal
            Component:  undetermined    |                  Version:  4.2
             Keywords:  decklink        |               Blocked By:
             Blocking:                  |  Reproduced by developer:  0
Analyzed by developer:  0               |
----------------------------------------+----------------------------------
 Summary of the bug:
 How to reproduce:
 {{{
 ffmpeg  \
 -loglevel debug \
 -fflags nobuffer \
 -f x11grab \
 -i :$DISPLAY \
 -f alsa \
 -i hw:11,1 \
 -ac 2 \
 -ar 48000 \
 -vf interlace=scan=tff:lowpass=complex,scale=1920:1080 \
 -pix_fmt uyvy422 \
 -format_code Hi50 \
 -f decklink \
 -top 1 \
 -flags:v +ildct+ilme \
 -r 25000/1000 \
   "DeckLink Quad ($SDIO)" #2>1 >/dev/null &
 ffmpeg version
 built on Ubuntu 18.04

 ffmpeg version N-100906-gad2cc0e2f4 Copyright (c) 2000-2021 the FFmpeg
 developers
   built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
   configuration: --prefix=/root/ffmpeg_build --pkg-config-flags=--static
 --extra-cflags='-I/root/ffmpeg_build/include
 -I/root/ffmpeg_sources/BMD_SDK/include' --extra-
 ldflags=-L/root/ffmpeg_build/lib --extra-libs='-lpthread -lm'
 --bindir=/root/bin --enable-gpl --enable-libass --enable-libfdk-aac
 --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-
 libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-
 nonfree --enable-decklink --enable-libxcb
   libavutil      56. 64.100 / 56. 64.100
   libavcodec     58.119.100 / 58.119.100
   libavformat    58. 65.101 / 58. 65.101
   libavdevice    58. 11.103 / 58. 11.103
   libavfilter     7.100.100 /  7.100.100
   libswscale      5.  8.100 /  5.  8.100
   libswresample   3.  8.100 /  3.  8.100
   libpostproc    55.  8.100 / 55.  8.100
 Hyper fast Audio and Video encoder

 }}}


 For some reason whenever i execute the above command without loglevel
 debug the command hangs. when trying to troubleshoot with the debug
 command it is running fine and without any problems except for the
 overhead of the extra logging.
 I am in no way capable to troubleshoot why this might be happening but if
 any information is required id be glad to provide.
 Some extra info:
 SDI card=Decklink Quad2
 happens on all SDI outputs =yes
 happens without audio input =seems not to for some reason.
 $display and $GPIO are pushed from other scripts but can be hardcoded to
 be display :11 and GPIO 1-7.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/9093>
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