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• Problem compiling ffmpeg with nvenc using visual studio 2015 community edition

  23 février 2020, par Uri Raz

  I’m trying to build ffmpeg w/ nvenc on Windows 10 64 bit and visual studio 2015 community edition. The command from step 10 in the Using FFmpeg with NVIDIA GPU Hardware Acceleration doc :

  ./configure —enable-nonfree —enable-cuda-sdk —enable-libnpp –-toolchain=msvc —extra-cflags=-I../nv_sdk —extraldflags=-libpath :../nv_sdk

  Gives me the error ’Unknown option "–-toolchain=msvc"’

  Background : I’ve executed the commands (changed the path in the first, I’m not sure its right) :

  export PATH="/C/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/Hostx64/x64/" :$PATH
  export PATH="/c/Program Files/NVIDIA GPU Computing Toolkit/CUDA/v10.0/bin/" :$PATH

  And ../nv_sdk has the subdirectories include & bin, copied from the NVIDIA GPU Computing Toolkit directory.

• Vcpkg building FFmpeg with libxml2

  15 décembre 2019, par Subestima

  First off all im a newbie in this area so if im asking something really stupid or non sense im sorry in advance, so lets get right to the point... im trying to add features to the ffmpeg, and by what i know i have to modify CONTROL file and portfile.cmake but as it seems its not enough i dont understand the errors and i cant get more info about this in the internet so if you could give me some info how to do it properly it would allready mean a lot to me ! i will leave the portions of code and error file

  **portfile.cmake:**
  
  if("libxml2" IN_LIST FEATURES)
  
      set(OPTIONS "${OPTIONS} --enable-libxml2")
  
  endif()
  
  
  
  **CONTROL:**
  
  Feature: libxml2
  
  Description: Libxml2 is the XML C parser and toolkit developed for the Gnome project (but usable outside of the Gnome platform)
  
  Build-Depends: zlib, libiconv, liblzma
  
  
  
  **Command Prompt after (vcpkg install ffmpeg[libxml2]:x64-windows)**
  
  CMake Error at scripts/cmake/vcpkg_execute_required_process.cmake:72 (message):
  
      Command failed: C:/vcpkg/downloads/tools/msys2/msys64/usr/bin/bash.exe --noprofile --norc C:/vcpkg/ports/ffmpeg\build.sh C:/vcpkg/buildtrees/ffmpeg/x64-windows-rel C:/vcpkg/buildtrees/ffmpeg/src/n4.2-02d8c63f80 C:/vcpkg/packages/ffmpeg_x64-windows "--enable-asm --enable-yasm --disable-doc --enable-debug --enable-runtime-cpudetect --enable-libxml2 --disable-openssl --disable-ffmpeg --disable-ffplay --disable-ffprobe --disable-libvpx --disable-libx264 --disable-opencl --disable-lzma --disable-bzlib --enable-avresample  --disable-static --enable-shared --extra-cflags=-DHAVE_UNISTD_H=0  --extra-cflags=-MD --extra-cxxflags=-MD"
  
      Working Directory: C:/vcpkg/buildtrees/ffmpeg/x64-windows-rel
  
      Error code: 1
  
      See logs for more information:
  
        C:\vcpkg\buildtrees\ffmpeg\build-x64-windows-rel-out.log
  
  
  
  Call Stack (most recent call first):
  
    ports/ffmpeg/portfile.cmake:197 (vcpkg_execute_required_process)
  
    scripts/ports.cmake:94 (include)
  
  
  
  
  
  Error: Building package ffmpeg:x64-windows failed with: BUILD_FAILED
  
  Please ensure you're using the latest portfiles with `.\vcpkg update`, then
  
  submit an issue at https://github.com/Microsoft/vcpkg/issues including:
  
    Package: ffmpeg:x64-windows
  
    Vcpkg version: 2019.09.12-nohash**strong text**
  
  
  
  **Log Error file:**
  
  === CONFIGURING === ERROR: libxml-2.0 not found using pkg-config
  
  
  
  If you think configure made a mistake, make sure you are using the latest version from Git.  If the latest version fails, report the problem to the ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net. Include the log file "ffbuild/config.log" produced by configure as this will help solve the problem.

  Thank you for your attention,
  Regards Pedro Cunha !

• Programmatically get non-overlapping images from MP4

  16 novembre 2019, par Carlos F

  My ultimate goal is to get meaningful snapshots from MP4 videos that are either 30 min or 1 hour long. "Meaningful" is a bit ambitious, so I have simplified my requirements.

  The image should be crisp - non-overlapping, and ideally not blurry. Initially, I thought getting a keyframe would work, but I had no idea that keyframes could have overlapping images embedded in them like this :

  Of course, some keyframe images look like this and those are much better :

  

  I was wondering if someone might have source code to :

  Take a sequence of say 10-15 continuous keyframes (jpg or png) and identify the best keyframe from all of them.

  This must happen entirely programmatically. I found this paper : http://research.microsoft.com/pubs/68802/blur_determination_compressed.pdf

  and felt that I could "rank" a few images based on the above paper, but then I was dissuaded by this link : Extracting DCT coefficients from encoded images and video given that my source video is an MP4. Of course, this confuses me because the input into the system is just a sequence of jpg images.

  Another link that is interesting is :

  Detection of Blur in Images/Video sequences

  However, I am not sure if this will work for "overlapping" images.