Recherche avancée

Sur d’autres sites (13366)

• Capturing output file of ffmpeg with vid.stab in python into a variable

  24 mars 2019, par M. Valter

  I’m trying to write a python script to stabilize videos using ffmpeg and the vid.stab library.
  My problem is that the output file doesn’t seem to go through stdout, so using subprocess.Popen() returns an empty variable.

  cmd1=["ffmpeg", "-i","./input.MOV", "-vf", "vidstabdetect=stepsize=6:shakiness=10:accuracy=15", "-f","null","pipe:1"]
  
  p = subprocess.Popen(cmd1, stdout=subprocess.PIPE)
  
  vectors, err = p.communicate()

  The issues is that vibstabdetect takes a filter called result, and outputs a file to whatever’s specified there, and stdout remains empty. (If there’s no result specified it defaults to transforms.trf.)

  Is there a way to get the contents of the result file ?
  When running the script with the code above it executes without error, but the file is created with the default name and the variable remains empty.

• PKG_CONFIG_PATH can't be seen by configure

  23 mars 2019, par Hashim

  I’m using Cygwin to compile a MinGW version of FFmpeg (I already use Cygwin so it didn’t make sense to use anything else to build).

  I was originally getting an error that someone on the Doom9 forums suggested might be due to mixing MinGW-64 and Cygwin dependencies. I then compiled or sourced MinGW-64 versions of all of the required dependencies (as some dependencies could not be compiled with Cygwin alone), and FFmpeg still fails to configure, always with the same error.

  This error is always a variation of "package not found using pkg-config" - if libaom is enabled, I get :

  ERROR : aom >= 1.0.0 not found using pkg-config

  If I don’t add —enable-libaom in the configure script, I get :

  ERROR : libass not found using pkg-config

  I’m running the following on the command line, in a single shell, to compile FFmpeg :

  cd /ffmpeg_sources/ffmpeg && export PKG_CONFIG_PATH="/usr/local/lib/pkgconfig" && 
  
  ./configure --arch=x86_64 --cross-prefix=x86_64-w64-mingw32- --target-os=mingw32 \
  
  --prefix="/usr/local" \
  
  --extra-cflags="-I/usr/local/include -static" \
  
  --extra-ldflags="-L/usr/local/lib -static" \
  
  --pkg-config-flags="--static" \
  
  --extra-libs="-pthread -lm" \
  
  --enable-libaom \
  
  --enable-libass \
  
  --enable-libfdk-aac \
  
  --enable-libfreetype \
  
  --enable-libmp3lame \
  
  --enable-libopus \
  
  --enable-libvorbis \
  
  --enable-libvpx \
  
  --enable-libx264 \
  
  --enable-libx265 \
  
  --enable-gpl \
  
  --enable-nonfree \
  
  --enable-static  \
  
  --disable-shared && 
  
  make -j$(nproc) && 
  
  make install

  A similar question [here] indicates that it’s an issue with PKG_CONFIG_PATH not seeing the packages in /usr/local/lib/pkgconfig, but when I do :

  cd /ffmpeg_sources/ffmpeg && PKG_CONFIG_PATH="/usr/local/lib/pkgconfig" && pkg-config --exists --print-errors aom && echo $?

  ...it returns a 0, indicating aom.pc was found in the PKG_CONFIG_PATH - which either rules out an issue with PKG_CONFIG_PATH or makes it a very specific one in which only configure and make aren’t able to see PKG_CONFIG_PATH, despite being run from the same shell just a moment after.

  How can I resolve this ?

  ---

  EDIT

  I did some further investigation by looking into ffbuild/config.log, and noticed that it shows a warning :

  WARNING : x86_64-w64-mingw32-pkg-config not found, library detection
  may fail.

  However, doing apt-cyg search x86_64-w64-mingw32-pkg-config shows that particular package as being installed.

  Sure enough, in the /bin folder, there is an extensionless file called x86_64-w64-mingw32-pkg-config, with the following contents :

  #!/bin/sh
  
  exec pkgconf --personality=x86_64-w64-mingw32 $@

  I’ve also found the following related issues, in case they can help anyone else figure out what’s going on here :

  https://ffmpeg.org/pipermail/ffmpeg-devel/2012-June/126683.html

  Warning "i686-mingw32-pkg-config not found, library detection may fail" while cross compiling ffmpeg

  https://github.com/Microsoft/FFmpegInterop/issues/106

  https://gitlab.gnome.org/GNOME/librsvg/issues/239

  https://ffmpeg.zeranoe.com/forum/viewtopic.php?t=2041

• Banding/ Trailing while resizing GIF with transparency using FFMPEG

  30 septembre 2019, par Arpit Kumar

  I am trying to resize a gif using ffmpeg. link here

  This is the command for resizing GIF

  ffmpeg -i default.gif -filter_complex "[0:v] scale=320:-1:flags=lanczos,split [a][b]; [a] palettegen=reserve_transparent=on:transparency_color=ffffff [p]; [b][p] paletteuse" resize.gif

  The problem is with the output. The output GIF has huge "banding/ trailing" effect

  Sample output of the file is here Output here

  I am not sure what is it that I am doing wrong and how can I fix this banding/ trailing effect.

  I am using FFMPEG on macOS Mojave, ffmpeg version is 4.1.1. Below is the output of the command

  ffmpeg version 4.1.1 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/openjdk-11.0.2.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/openjdk-11.0.2.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  Input #0, gif, from 'ear_s_01.gif':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: gif, bgra, 640x480, 12.50 fps, 12.50 tbr, 100 tbn, 100 tbc
  
  Stream mapping:
  
    Stream #0:0 (gif) -> scale
  
    paletteuse -> Stream #0:0 (gif)
  
  Press [q] to stop, [?] for help
  
  Output #0, gif, to 'resize.gif':
  
    Metadata:
  
      encoder         : Lavf58.20.100
  
      Stream #0:0: Video: gif, pal8, 320x240, q=2-31, 200 kb/s, 12.50 fps, 100 tbn, 12.50 tbc
  
      Metadata:
  
        encoder         : Lavc58.35.100 gif
  
  [Parsed_palettegen_2 @ 0x7f7f19001180] 255(+1) colors generated out of 91324 colors; ratio=0.002792
  
  [Parsed_palettegen_2 @ 0x7f7f19001180] Dupped color: FF100C0A
  
  frame=   37 fps=0.0 q=-0.0 Lsize=     453kB time=00:00:02.89 bitrate=1283.8kbits/s speed=7.33x    
  
  video:452kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.237091%