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• Building and using OpenCV as a static library with Ffmpeg

  11 octobre 2016, par Matt Hammond

  I’m trying write an OpenCV application. I’ve statically built OpenCV from source as I don’t want dll files and my project compiles as long as I don’t use cv::VideoCapture, in which case I get a link error LNK2019 unresolved external symbol.

  I think this is because the cv::VideoCapture uses ffmpeg to work with video, which, because of it’s license, cannot be statically linked in my project. I would be ok with linking the ffmpeg dynamically but I’m having trouble doing this. There is a opencv_ffmpeg310_64.dll file in the %OpenCV_DIR%\bin folder, but I’m clueless about how to dynamically link it to my project. Usually I have .lib files that come with the .dll but I can’t find them anywhere.

  Is it possible to statically link OpenCV and dynamically link ffmpeg, and how should I go about doing this ?

  Additional info :

  • Windows 10
  • Visual Studio 2015
  • OpenCV 3.1.0 x64 build

• FFMPEG : Writing raw planar sample format into a file

  24 juin 2013, par user2439801

  i've started using ffmpeg on Visual Studio 2010 and encounter some problem on writing planar audio samples into a file.

  For packed sample format i just use :

  fwrite(audio_data[0], 1, audio_bufsize, audio_file); 

  where audio_data[0] is my buffer and audio_buffsize is the size of my buffer and audio_file is the pointer to my file.

  When i use this line to write packed sample format everything seems to be fine, but when i try to write planar sample format i got the sound but with a lot of noises.

  So is there better (or correct) way to write planar sample format or do i have to resample it into packed sample format ?

  Thanks

• Need help to compile FFmpeg with MSVC tools

  30 janvier 2018, par Antwane

  I need to compile FFmpeg on Windows 10 using MSVC 2017 compiler. I followed some guides from :

  • https://trac.ffmpeg.org/wiki/CompilationGuide/MSVC
  • https://www.ffmpeg.org/platform.html#Microsoft-Visual-C_002b_002b-or-Intel-C_002b_002b-Compiler-for-Windows
  • https://pracucci.com/compile-ffmpeg-on-windows-with-visual-studio-compiler.html

  I installed current stable version of MSYS, fixed link.exe and use of PATH environment, installed make diffutils gcc pkg-config and downloaded c99-to-c89, nasm, and inttypes.h

  I think my environment is now correctly set up, I ran MSYS shell from MSVC Command prompt and have everything reachable.

  $ which cl
  
  /c/Program Files (x86)/Microsoft Visual Studio/2017/Professional/VC/Tools/MSVC/14.12.25827/bin/HostX64/x64/cl
  
  
  
  $ which link
  
  /c/Program Files (x86)/Microsoft Visual Studio/2017/Professional/VC/Tools/MSVC/14.12.25827/bin/HostX64/x64/link
  
  
  
  $ which yasm
  
  /home/Antoine/bin/yasm
  
  
  
  $ which c99conv
  
  /home/Antoine/bin/c99conv
  
  
  
  $ which c99wrap
  
  /home/Antoine/bin/c99wrap

  Now I configure the build

  $ ./configure --toolchain=msvc
  
  install prefix            /usr/local
  
  source path               .
  
  C compiler                cl
  
  C library                 msvcrt
  
  ARCH                      x86 (generic)
  
  big-endian                no
  
  runtime cpu detection     yes
  
  standalone assembly       yes
  
  x86 assembler             nasm
  
  MMX enabled               yes
  
  MMXEXT enabled            yes
  
  3DNow! enabled            yes
  
  3DNow! extended enabled   yes
  
  SSE enabled               yes
  
  SSSE3 enabled             yes
  
  AESNI enabled             yes
  
  AVX enabled               yes
  
  AVX2 enabled              yes
  
  XOP enabled               yes
  
  FMA3 enabled              yes
  
  FMA4 enabled              yes
  
  i686 features enabled     yes
  
  CMOV is fast              yes
  
  EBX available             no
  
  EBP available             no
  
  debug symbols             yes
  
  strip symbols             no
  
  optimize for size         no
  
  optimizations             yes
  
  static                    yes
  
  shared                    no
  
  postprocessing support    no
  
  network support           yes
  
  threading support         w32threads
  
  safe bitstream reader     yes
  
  texi2html enabled         no
  
  perl enabled              no
  
  pod2man enabled           no
  
  makeinfo enabled          no
  
  makeinfo supports HTML    no
  
  
  
  External libraries:
  
  schannel                 xlib
  
  
  
  External libraries providing hardware acceleration:
  
  cuda                     cuvid                    d3d11va                  dxva2                    nvenc
  
  
  
  Libraries:
  
  avcodec                  avdevice                 avfilter                 avformat                 avutil                   swresample               swscale
  
  
  
  Programs:
  
  ffmpeg                   ffprobe
  
  
  
  [...]
  
  Hundreds of modules, library, etc.
  
  [...]
  
  
  
  License: LGPL version 2.1 or later
  
  Creating configuration files ...
  
  config.h is unchanged
  
  config.asm is unchanged
  
  libavutil/avconfig.h is unchanged
  
  libavcodec/bsf_list.c is unchanged
  
  libavformat/protocol_list.c is unchanged

  But when I run make it stops very quickly

  $ make
  
  Makefile:47: la cible « qt-faststart » ne correspond pas au motif de cible
  
  Makefile:47: la cible « trasher » ne correspond pas au motif de cible
  
  Makefile:47: la cible « uncoded_frame » ne correspond pas au motif de cible
  
  Makefile:91: ffbuild/library.mak: No such file or directory
  
  make: *** Aucune règle pour fabriquer la cible « ffbuild/library.mak ». Arrêt.

  Sorry for the french wording, I don’t know how to tell MSVC print its output in english. Basically, the error means :

  Makefile:47: target « qt-faststart » doesn't match the target pattern
  
  make: *** No rule to make target « ffbuild/library.mak ». Stopped.

  Side notes :

  $ tree ffbuild
  
  ffbuild
  
  ├── config.fate
  
  ├── config.log
  
  ├── config.mak
  
  └── config.sh

  That’s right, library.mak were not generated into ffbuild, but I don’t know why, and configure script didn’t output any error message...

  Does anybody can help me to find out what am I doing wrong ?

  Edit :

  make distclean doesn’t help

  $ make distclean
  
  Makefile:47: la cible « qt-faststart » ne correspond pas au motif de cible
  
  Makefile:47: la cible « trasher » ne correspond pas au motif de cible
  
  Makefile:47: la cible « uncoded_frame » ne correspond pas au motif de cible
  
  Makefile:91: ffbuild/library.mak: No such file or directory
  
  make: *** Aucune règle pour fabriquer la cible « ffbuild/library.mak ». Arrêt.