[FFmpeg-trac] #9994(undetermined:new): ffmpeg 5.1 cli changed how it interprets percent signs in output file urls

[FFmpeg]

#9994: ffmpeg 5.1 cli changed how it interprets percent signs in output file urls
-------------------------------------+-------------------------------------
             Reporter:  mkhl         |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 in ffmpeg 5.0 one had to "escape" percent signs in output file urls, so
 instead of {{{100%.png}}} one had to pass {{{100%%.png}}}.
 in ffmpeg 5.1 this changed and percent signs are now interpreted
 literally, and i can't find any documentation regarding whether this
 change was intentional or which variant people should use.

 See also:
 [https://github.com/yt-dlp/yt-dlp/issues/4604 yt-dlp issue about how it's
 affected by this bug]

 How to reproduce:
 {{{
 % convert xc:#ffffff -size 1x1 white.png # so there's any image
 % ffmpeg -y -loglevel repeat+info -f image2 -pattern_type none -i
 'file:white.png' -movflags +faststart 'file:x%%.webp'
 ffmpeg version n5.1.2 Copyright (c) 2000-2022 the FFmpeg developers
   built with gcc 12.2.0 (GCC)
   configuration: --prefix=/usr --disable-debug --disable-static --disable-
 stripping --enable-amf --enable-avisynth --enable-cuda-llvm --enable-lto
 --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-
 ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b
 --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi
 --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmfx
 --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb
 --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-
 libpulse --enable-librav1e --enable-librsvg --enable-libsoxr --enable-
 libspeex --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-
 libtheora --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-
 libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-
 libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-libzimg
 --enable-nvdec --enable-nvenc --enable-opencl --enable-opengl --enable-
 shared --enable-version3 --enable-vulkan
   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
 Input #0, image2, from 'file:white.png':
   Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
   Stream #0:0: Video: png, monob(pc), 1x1, 25 fps, 25 tbr, 25 tbn
 Stream mapping:
   Stream #0:0 -> #0:0 (png (native) -> webp (libwebp_anim))
 Press [q] to stop, [?] for help
 Output #0, webp, to 'file:x%%.webp':
   Metadata:
     encoder         : Lavf59.27.100
   Stream #0:0: Video: webp, bgra(pc, gbr/unknown/unknown, progressive),
 1x1, q=2-31, 200 kb/s, 25 fps, 1k tbn
     Metadata:
       encoder         : Lavc59.37.100 libwebp_anim
 [libwebp_anim @ 0x562536100940] Using libwebp for RGB-to-YUV conversion.
 You may want to consider passing in YUV instead for lossy encoding.
 frame=    1 fps=0.0 q=-0.0 Lsize=       0kB time=00:00:00.00 bitrate=
 352.0kbits/s speed=0.177x
 }}}

 with 5.0 this would create a file {{{x%.webp}}}, with 5.1 it creates
 {{{x%%.webp}}} instead
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9994>
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