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• compiling ffmpeg 2.3 for android with NDK r10 on windows [duplicate]

  25 août 2014, par L.Grillo

  This question already has an answer here :

  • How to compile ffmpeg-2.2.2 on windows with cygwin and android ndk r9c
    
    1 answer
    

  After a week i’m trying to compile ffmpeg for android.
  I can’t find a static build in the entire web exept for https://github.com/guardianproject/android-ffmpeg-java/tree/master/res/raw but is 0.11 version one.

  This is my build.sh

  #!/usr/bin/env bash
  
  
  
  NDK=C:/Android/android-ndk-r10
  
  SYSROOT=$NDK/platforms/android-18/arch-arm/
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64
  
  
  
  function build_one
  
  {
  
  ./configure \
  
      --arch=arm \
  
      --target-os=linux \
  
      --enable-runtime-cpudetect \
  
      --enable-pic \
  
      --disable-shared \
  
      --enable-static \
  
      --extra-cflags='-march=armv6' \
  
      --extra-ldflags="$ADDI_LDFLAGS" \
  
      --enable-ffmpeg \
  
      --disable-ffplay \
  
      --disable-ffprobe \
  
      --disable-ffserver\
  
      --disable-network \
  
      --enable-cross-compile \
  
      --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
      --sysroot=$SYSROOT \
  
      $ADDITIONAL_CONFIGURE_FLAG
  
  make clean
  
  make -j4
  
  make install
  
  }
  
  
  
  CPU=arm
  
  PREFIX=$(pwd)/android/$CPU
  
  ADDI_CFLAGS="-marm"
  
  
  
  build_one

  It seems everything works good except the compilation stopped after 4 files :

  

  It seems to stay here forever. After 4 hours nothing is moving.
  the process "make.exe (32 bit)" is running with 18% of cpu

  Any help will be precious.
  Thank u

• OpenCV VideoWriter will not open

  21 février 2015, par ChrisC

  I’m having trouble instantiating and opening an OpenCV VideoWriter for recording video on a Raspberry Pi (Raspbian Weezy).

  My project is written in C++, but I’ve written a minimal Python program that demonstrates the problem.

  https://gist.github.com/chriscollins/11ff2f43852e1c93dae8

  Both my C++ code and the Python code above run without problem on my Windows machine. Sometimes the writer does not open, but that’s to be expected - I don’t have all of the listed codecs installed (the list of codecs comes from the Open CV source), but a good number of them work correctly. However, on a Raspberry Pi, both the C++ code and the Python code fail with the VideoWriter never being opened. In the above Python code, writer.isOpened() returns false for every single codec, when run on a Raspberry Pi.

  I’ve chowned the destination directory to the user I’m running the Python script as, and chmodded it to 777 so I don’t believe that it is a permissions problem. I think it may be connected with how I’ve installed OpenCV or some of its dependencies, but I’m not sure how to rectify it.

  The install process I’ve used is as follows :

  1. Update firmware/packages via rpi-update, apt-get update and apt-get upgrade.

  2. Install the following dependencies via apt-get :

     libjpeg8
libjpeg8-dev
libjpeg8-dbg
libjpeg-progs
ffmpeg
libavcodec-dev
libavcodec53
libavformat53
libavformat-dev
libgstreamer0.10-0-dbg
libgstreamer0.10-0
libgstreamer0.10-dev
libxine1-ffmpeg
libxine-dev
libxine1-bin
libunicap2
libunicap2-dev
swig
libv4l-0
libv4l-dev
python-numpy
libpython2.6
python-dev
python2.6-dev
libgtk2.0-dev

  3. Download and unzip http://sourceforge.net/projects/opencvlibrary/files/opencv-unix/2.4.9/opencv-2.4.9.zip to /root/opencv-2.4.9.

  4. cd /root/opencv-2.4.9 and run cmake -DCMAKE_BUILD_TYPE=RELEASE -DCMAKE_INSTALL_PREFIX=/usr/local -DBUILD_PERF_TESTS=OFF -DBUILD_opencv_gpu=OFF -DBUILD_opencv_ocl=OFF. Output of cmake is available at https://gist.github.com/chriscollins/d8060e03a6acd6d4336c

  5. make and make install from the same directory.

  Various other OpenCV functionality works correctly on the Raspberry Pi (in C++ or in Python) - e.g. viewing a webcam via VideoCapture, but I can’t get the VideoWriter to work. I’m tempted to try installing FFMPEG from source instead of via apt-get, but as make takes 5+ hours to run on a Raspberry Pi, I was hoping I’d find the answer here, rather than proceeding with a trial and error approach !

  Any advice on how to solve (or debug) this is appreciated.

  EDIT : Added output of cmake command (https://gist.github.com/chriscollins/d8060e03a6acd6d4336c)

• FFMPEG video output size is too long

  12 mars 2021, par fahad

  I am trying to merge videos in FFmpeg reading through a .txt file, it merges the videos but increases the total timeline. Expected timeline is 2 minutes but after merging the videos the output file has a timeline of 18 hours.I am using the following command in my cmd :

  


  ffmpeg -f concat -i mylist.txt -c copy output.mp4