[FFmpeg-user] ffmpeg unexpectedly increases debug level for console messages

[Dmitry Katsubo]

Dear ffmpeg community,

I have ffmpeg for Windows x64 downloaded from https://www.gyan.dev/ffmpeg/builds/

When ffmpeg is started from CygWin or Windows WSL the following happens:

* It reports "error parsing debug value" and increases the debug level (verbosity of the messages printed to screen):

$ ffmpeg.exe -y -v warning -i in.avs -c:v libx264 -crf 28 -c:a libvorbis -q:a 5 out.mkv
Guessed Channel Layout for Input Stream #0.1 : stereo

error parsing debug value
debug=0
debug=1
[rawvideo @ 00000254d77ad040] PACKET SIZE: 3110400, STRIDE: 1620
[libx264 @ 00000254d77aeb40] frame=  46 QP=35.70 NAL=0 Slice:B Poc:88  I:123  P:4215 SKIP:3822 size=9439 bytes
[matroska @ 00000254d77be280] Writing block of size 366 with pts 1455, dts 1455, duration 21 at relative offset 701709 in cluster at offset 5095. TrackNumber 2, keyframe 1
[matroska @ 00000254d77be280] Writing block of size 9439 with pts 1470, dts 1470, duration 33 at relative offset 702082 in cluster at offset 5095. TrackNumber 1, keyframe 0
[rawvideo @ 00000254d77ad040] PACKET SIZE: 3110400, STRIDE: 1620ate=   8.9kbits/s speed=0.105x
...

* After a few frames the log is increased further:

[rawvideo @ 00000254d77ad040] PACKET SIZE: 3110400, STRIDE: 1620
[libx264 @ 00000254d77aeb40] frame=  53 QP=32.45 NAL=2 Slice:P Poc:112 I:1166 P:6007 SKIP:987  size=30394 bytes
[matroska @ 00000254d77be280] Writing block of size 363 with pts 1690, dts 1690, duration 21 at relative offset 802549 in cluster at offset 5095. TrackNumber 2, keyframe 1
[matroska @ 00000254d77be280] Writing block of size 30394 with pts 1870, dts 1703, duration 33 at relative offset 802919 in cluster at offset 5095. TrackNumber 1, keyframe 0
stream #1:
  keyframe=1
  duration=0.033
  dts=4.867  pts=4.867
  size=12800
stream #0:7 fps=2.9 q=34.0 size=       5kB time=00:00:04.83 bitrate=   8.4kbits/s speed=0.0964x
  keyframe=1
  duration=0.033
  dts=4.900  pts=4.900
  size=3110400
[rawvideo @ 00000254d77ad040] PACKET SIZE: 3110400, STRIDE: 1620

* Finally it starts dumping the stream to console:

[rawvideo @ 00000254d77ad040] PACKET SIZE: 3110400, STRIDE: 1620
[libx264 @ 00000254d77aeb40] frame= 138 QP=32.95 NAL=0 Slice:B Poc:272 I:82   P:3476 SKIP:4602 size=6445 bytes
[matroska @ 00000254d77be280] Writing block of size 365 with pts 4516, dts 4516, duration 21 at relative offset 2021003 in cluster at offset 5095. TrackNumber 2, keyframe 1
[matroska @ 00000254d77be280] Writing block of size 6445 with pts 4536, dts 4536, duration 33 at relative offset 2021375 in cluster at offset 5095. TrackNumber 1, keyframe 0
stream #1:
  keyframe=1
  duration=0.033
  dts=7.700  pts=7.700
  size=12800
00000000  56 51 1d 3d f4 7c 21 3d 2c 48 20 3d 05 f3 1d 3d VQ.=.|!=,H =...=
00000010  36 78 22 3d e5 7e 18 3d 1d 52 22 3d 4d 80 11 3d 6x"=.~.=.R"=M..=
00000020  5c b7 1f 3d 8c e1 0b 3d c4 33 1b 3d 12 db 08 3d \..=...=.3.=...=
00000030  86 0a 17 3d d3 08 07 3d 96 85 13 3d 88 e8 06 3d ...=...=...=...=
00000040  ad 1b 0f 3d 38 b5 09 3d 77 09 0c 3d 9d 23 0f 3d ...=8..=w..=.#.=
00000050  7b bb 0b 3d 25 8c 16 3d 8e bd 0a 3d 24 e2 1d 3d {..=%..=...=$..=
00000060  cf dc 08 3d 66 12 24 3d 70 44 06 3d 3c 66 28 3d ...=f.$=pD.=<f(=
...

Is this the expected behaviour or do I miss something? I don't observe the issue when ffmpeg is launched from Windows console.

Version:

$ ffmpeg.exe -version
ffmpeg version 5.1-full_build-www.gyan.dev Copyright (c) 2000-2022 the FFmpeg developers
built with gcc 12.1.0 (Rev2, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libx
ml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enab
le-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libweb
p --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --e
nable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable
-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libshaderc --enable-vulkan --enable-libplacebo --enable
-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --e
nable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-lads
pa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
libavutil      57. 28.100 / 57. 28.100
libavcodec     59. 37.100 / 59. 37.100
libavformat    59. 27.100 / 59. 27.100
libavdevice    59.  7.100 / 59.  7.100
libavfilter     8. 44.100 /  8. 44.100
libswscale      6.  7.100 /  6.  7.100
libswresample   4.  7.100 /  4.  7.100
libpostproc    56.  6.100 / 56.  6.100

Thanks in advance!

-- 
With best regards,
Dmitry