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• Why does ffmpeg cmake external project is not working

  24 mars 2019, par bottega

  I’m trying to compile ffmpeg with h264 support as an external cmake project. But after compile it, I’m getting libavcodec reference errors.

  The compile problem is occurring on Ubuntu 18.04 machine. I have installed all dependencies for ffmpeg and also libx264-dev.

  Cmake external project

  set( proj ffmpeg )
  
  set( SHARED_FFMPEG )
  
  
  
  
  
  set(BASIC
  
          --extra-ldflags=-L/usr/local/lib
  
          --extra-cflags=-I/usr/local/include
  
          --enable-gpl
  
          --enable-libx264)
  
  
  
  
  
  option( FFMPEG_GPL "Use a GPL version of FFMPEG" OFF )
  
  
  
  set(FFMPEG_INSTALL_DIR  ${CMAKE_BINARY_DIR}/INSTALL )
  
  
  
  ExternalProject_Add(${proj}
  
          # Set up dirs
  
          SOURCE_DIR ${CMAKE_BINARY_DIR}/${proj}
  
          INSTALL_DIR ${FFMPEG_INSTALL_DIR}
  
          # get the project
  
          GIT_REPOSITORY "https://github.com/FFmpeg/FFmpeg.git"
  
          GIT_TAG "n3.2.13"
  
  
  
          # Build the project
  
          BUILD_IN_SOURCE 1
  
  
  
          # Configure step
  
          # DO STH FOR THE ARCHITECTURE...
  
          CONFIGURE_COMMAND /configure --prefix=${FFMPEG_INSTALL_DIR} ${SHARED_FFMPEG} ${FFMPEG_GPL_FLAG} ${BASIC}
  
  
  
          #  BUILD_COMMAND ${CMAKE_MAKE_PROGRAM} -j${NProcessors}
  
          )
  
  
  
  # define the library suffix
  
  if( SUPER_SHARED_LIBS )
  
      if( APPLE )
  
          set(LIBRARY_SUFFIX .dylib)
  
      else( APPLE )
  
          set(LIBRARY_SUFFIX .so)
  
      endif( APPLE )
  
  else( SUPER_SHARED_LIBS )
  
      set(LIBRARY_SUFFIX .a)
  
  endif( SUPER_SHARED_LIBS )
  
  
  
  # ADD DIRECTORIES FOR DEPENDENCIES IN Main/CMakeLists.txt
  
  set( FFMPEG_LIBRARYS libavcodec.a
  
          libavformat.a
  
          libavutil.a
  
          libswscale.a
  
          )
  
  
  
  include_directories(${FFMPEG_INSTALL_DIR}/include)
  
  
  
  set(FFMPEG_LIBRARY_DIRS ${FFMPEG_INSTALL_DIR}/lib/)
  
  link_directories(${FFMPEG_LIBRARY_DIRS})

  C++ Where I used the library

  extern "C" {
  
  #include 
  
  #include 
  
  #include 
  
  
  
  #include "libavcodec/avcodec.h"
  
  #include "libavformat/avformat.h"
  
  #include "libavutil/mathematics.h"
  
  #include "libswscale/swscale.h"
  
  
  
  #define INBUF_SIZE 4096
  
  #define AUDIO_INBUF_SIZE 20480
  
  #define AUDIO_REFILL_THRESH 4096
  
  }
  
  
  
  ...
  
  
  
   fReceiveBuffer = new u_int8_t[DUMMY_SINK_RECEIVE_BUFFER_SIZE];
  
      fReceiveBufferAV = new u_int8_t[DUMMY_SINK_RECEIVE_BUFFER_SIZE+4];
  
      fReceiveBufferAV[0] = 0;
  
      fReceiveBufferAV[1] = 0;
  
      fReceiveBufferAV[2] = 0;
  
      fReceiveBufferAV[3] = 1;
  
  
  
  
  
      av_init_packet(&avpkt);
  
      avpkt.flags |= AV_PKT_FLAG_KEY;
  
      avpkt.pts = avpkt.dts = 0;
  
  
  
      av_init_packet(&avpkt);
  
      avpkt.flags |= AV_PKT_FLAG_KEY;
  
      avpkt.pts = avpkt.dts = 0;
  
  
  
      /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
  
      memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
  
  
  
      //codec = avcodec_find_decoder(CODEC_ID_MPEG1VIDEO);
  
      codec = avcodec_find_decoder(AV_CODEC_ID_H264);
  
  
  
  ...

  Error :

  [100%] Linking CXX executable ../../bin/awesom-o
  
  /home/tiburcio/CLionProjects/awesom-o/cmake-build-debug/INSTALL/lib/libavcodec.a(libx264.o): In function `X264_frame':
  
  /home/tiburcio/CLionProjects/awesom-o/cmake-build-debug/ffmpeg/libavcodec/libx264.c:280: undefined reference to `x264_picture_init'
  
  /home/tiburcio/CLionProjects/awesom-o/cmake-build-debug/INSTALL/lib/libavcodec.a(libx264.o): In function `reconfig_encoder':
  
  /home/tiburcio/CLionProjects/awesom-o/cmake-build-debug/ffmpeg/libavcodec/libx264.c:266: undefined reference to `x264_encoder_reconfig'
  
  /home/tiburcio/CLionProjects/awesom-o/cmake-build-debug/INSTALL/lib/libavcodec.a(libx264.o): In function `X264_frame':
  
  /home/tiburcio/CLionProjects/awesom-o/cmake-build-debug/ffmpeg/libavcodec/libx264.c:340: undefined reference to `x264_encoder_encode'

• Screenshot of video file in Electron Angular project without ffmpeg

  15 juin 2022, par Gary Klasen

  Within my Electron Angular project, I want to preview a video file which is stored locally on Windows / MacOS within a frame, like this :

  


  

  


  On the left side, currently, there is a placeholder image. But i want to have a snapshot out of the video, it is not important at which position of the video this is taken.

  


  Our attempt at the moment is to use fluent-ffmpeg library from npm :

  


  var ffmpeg = require('fluent-ffmpeg');

let command = new ffmpeg({source: "MY_VIDEO_PATH"}).inputOptions('-protocol_whitelist file,http,https,tcp,tls,crypto')

command.takeScreenshots({
    count: 1,
    timemarks: ['5%'],
    filename: "MY_FILENAME"
}, "DESTINATION_FOLDER_PATH_FOR_THUMB");


  


  It takes the screen after 5% of the video would have been played. However, this requires ffmpeg executable to be present, which actually costs more space for the application as we want to use.

  


  So : Can i pick out a screenshot out of a video file without using additional executables like ffmpeg ? If there are some suitable npm libaries, this would be also fine, as they are a lot smaller.

  


• Revision 8fc3ab774f : Enable dual arf with constant q. Add second level arf Q adjustment when using d

  22 octobre 2014, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_encoder.c

  
   Modify /vp9/encoder/vp9_ratectrl.c

  
  
  Enable dual arf with constant q.

  Add second level arf Q adjustment when using dual arfs
  in constant Q mode.

  Previously in constant Q mode enabling dual arf hurt by 5%
  but with this change the average benefit is 1-1.5% with some
  mid range data points up 10%.

  Note however that it still hurts on some clips including
  some very low motion show content.

  Change-Id : I5b7789a2f42a6127d9e801cc010c20a7113bdd9b