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• Android Java — Using and building FFMPEG library in Android Studio(Cmake)

  12 septembre 2017, par y3k00000

  As title, I’m trying to use the ffmpeg source code as library in Android Studio on Ubuntu Linux, but meeting some trouble in compilation stage. I think I must be missing some compile option but having no idea what I miss, can somebody lend a hand ?

  My codes & settings are below :

  A simple auto-generated .cpp

  #include 
  
  #include <string>
  
  #include "libavcodec/aacenc.h"
  
  
  
  extern "C"
  
  JNIEXPORT jstring JNICALL
  
  Java_y3k_testffmpegnative_MainActivity_stringFromJNI(
  
          JNIEnv *env,
  
          jobject /* this */) {
  
      std::string hello = "Hello from C++";
  
      return env->NewStringUTF(hello.c_str());
  
  }
  
  
  
  AACEncContext * aacEncContext; // Just trying by adding this.
  
  </string>

  I’ve tried these Gradle setting and it didn’t help :

  android {
  
      ....
  
      externalNativeBuild {
  
          cmake {
  
              arguments "-DANDROID_TOOLCHAIN=clang"
  
              cFlags "-std=c99"
  
              cppFlags "-frtti","-fexceptions"
  
          }
  
      }
  
  }
  
  ....

  CMakeLists.txt

  (Android Studio generated)
  
  ....
  
  include_directories( /home/y3k/ffmpeg )

  Error message while compiling :

  /home/y3k/ffmpeg/libavutil/float_dsp.h
  
  Error:(164, 50) error: expected ')'
  
  Information:(164, 30) to match this '('
  
  Error:(164, 50) error: expected ')'
  
  Information:(164, 30) note: to match this '('
  
  /home/y3k/ffmpeg/libavutil/fixed_dsp.h
  
  Error:(153, 44) error: expected ')'
  
  Information:(153, 30) to match this '('
  
  Error:(153, 44) error: expected ')'
  
  Information:(153, 30) note: to match this '('
  
  /home/y3k/ffmpeg/libavcodec/mpeg4audio.h
  
  Error:(44, 8) error: unknown type name 'av_export'
  
  Error:(44, 18) error: expected unqualified-id
  
  Error:(44, 8) error: unknown type name 'av_export'
  
  Error:(44, 18) error: expected unqualified-id
  
  /home/y3k/ffmpeg/libavcodec/aac.h
  
  Error:(294, 21) error: expected member name or ';' after declaration specifiers
  
  Error:(294, 21) error: expected member name or ';' after declaration specifiers

  FFMpeg config.h generated by this script :

  NDK=/home/y3k/Android/Sdk/ndk-bundle
  
  SYSROOT=$NDK/platforms/android-23/arch-arm/
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64
  
  function build_one
  
  {
  
  ./configure \
  
   --prefix=$PREFIX \
  
   --disable-shared \
  
   --enable-static \
  
   --disable-doc \
  
   --disable-ffmpeg \
  
   --disable-ffplay \
  
   --disable-ffprobe \
  
   --disable-ffserver \
  
   --disable-avdevice \
  
   --disable-doc \
  
   --disable-symver \
  
   --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
   --target-os=linux \
  
   --arch=arm \
  
   --enable-cross-compile \
  
   --sysroot=$SYSROOT \
  
   --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
  
   --extra-ldflags="$ADDI_LDFLAGS" \
  
   $ADDITIONAL_CONFIGURE_FLAG
  
  make clean
  
  make
  
  make install
  
  }
  
  CPU=arm
  
  PREFIX=$(pwd)/android/$CPU
  
  ADDI_CFLAGS="-marm"
  
  build_one

  By tracing the errors I found these lines :

  in float_dsp.h, fixed_dsp.h :

  void (*butterflies_float)(float *av_restrict v1, float *av_restrict v2, int len);

  av_restrict defined in config.h

  #define av_restrict restrict

  in aac.h :

  ....
  
  struct AACContext {
  
      AVClass        *class;
  
  ....

  in mpeg4audio.h :

  extern av_export const int avpriv_mpeg4audio_sample_rates[16];

  So I’m guessing it’s because the compiler misrecognized the C code as C++, I tried adding these :

  arguments "-DANDROID_TOOLCHAIN=clang"
  
  cFlags "-std=c99"

  to my build.gradle but didn’t help. Having no idea where to move on. :(

  I’m using the latest stable version of Android Studio on Ubuntu desktop. Please don’t be hesitate to ask if any extra information is required.

  Also I’ve been tried edit my native-lib.cpp into .c (Surely with the code contents changed), but wasn’t working either.

  Appreciate for any help.

• Revision a9a1eac6c7 : tests : fix Continue() signatures they're const member functions, they need to m

  8 août 2012, par James Zern

  Changed Paths : Modify /test/config_test.cc Modify /test/keyframe_test.cc tests : fix Continue() signatures they're const member functions, they need to match the base class to be called Change-Id : Id0580c5078b5876ead6731d95d8b86fef4029c40

• Color Correcting MP4/Webm videos

  2 octobre 2014, par sottenad

  I have a large video that features some animations too complex/long for other methods of embedding (gif, png sequence, etc.) and we are running into an issue with the colors in the video. Essentially we are including the background of the web page as part of the video in order to prevent the appearance of any edges on the video when it plays. We are trying to get the gradient background on the video to match that on the webpage, but the colors are WAY off.

  Are there any recommendations on how to color correct an MP4 video ? Or any html5-safe ways to do video with an alpha channel ?