Recherche avancée

Sur d’autres sites (3520)

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

  8 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.

• Why I became a HTML5 co-editor

  15 août 2012, par silvia

  A few weeks ago, I had the honor to be appointed as part of the editorial team of the W3C HTML5 specification.

  Since Ian Hickson had recently decided to focus solely on editing the WHATWG HTML living standard specification, the W3C started looking for other editors to take the existing HTML5 specification to REC level. REC level is what other standards organizations call a “ratified standard”.

  But what does REC level really mean for HTML ?

  In my probably somewhat subjective view, recommendation level means that a snapshot is taken of the continuously evolving HTML spec, which has a comprehensive feature set, that is implemented in a cross-browser interoperable way, has a complete test set for the features, and has received wide review. The latter implies that other groups in the W3C have had a chance to look at the specification and make sure it satisfies their basic requirements, which include e.g. applicability to all users (accessibility, internationalization), platforms, and devices (mobile, TV).

  Basically it means that we stop for a “moment”, take a deep breath, polish the feature set that we’ve been working on this far, and make sure we all agree on it, before we get back to changing the world with cool new stuff. In a software project we would call it a release branch with feature freeze.

  Now, as productive as that may sound for software – it’s not actually that exciting for a specification. Firstly, the most exciting things happen when writing new features. Secondly, development of browsers doesn’t just magically stop to get the release (REC) happening. And lastly, if we’ve done our specification work well, there should be only little work to do. Basically, it’s the unthankful work of tidying up that we’re looking at here.

  So, why am I doing it ? I am not doing this for money – I’m currently part-time contracting to Google’s accessibility team working on video accessibility and this editor work is not covered by my contract. It wasn’t possible to reconcile polishing work on a specification with the goals of my contract, which include pushing new accessibility features forward. Therefore, when invited, I decided to offer my spare time to the W3C.

  I’m giving this time under the condition that I’d only be looking at accessibility and video related sections. This is where my interest and expertise lie, and where I’m passionate to get things right. I want to make sure that we create accessibility features that will be implemented and that we polish existing video features. I want to make sure we don’t digress from implementations which continue to get updated and may follow the WHATWG spec or HTML.next or other needs.

  I am not yet completely sure what the editorship will entail. Will we look at tests, too ? Will we get involved in HTML.next ? This far we’ve been preparing for our work by setting up adequate version control repositories, building a spec creation process, discussing how to bridge to the WHATWG commits, and analysing the long list of bugs to see how to cope with them. There’s plenty of actual text editing work ahead and the team is shaping up well ! I look forward to the new experiences.

• Why I became a HTML5 co-editor

  1er janvier 2014, par silvia

  A few weeks ago, I had the honor to be appointed as part of the editorial team of the W3C HTML5 specification.

  Since Ian Hickson had recently decided to focus solely on editing the WHATWG HTML living standard specification, the W3C started looking for other editors to take the existing HTML5 specification to REC level. REC level is what other standards organizations call a “ratified standard”.

  But what does REC level really mean for HTML ?

  In my probably somewhat subjective view, recommendation level means that a snapshot is taken of the continuously evolving HTML spec, which has a comprehensive feature set, that is implemented in a cross-browser interoperable way, has a complete test set for the features, and has received wide review. The latter implies that other groups in the W3C have had a chance to look at the specification and make sure it satisfies their basic requirements, which include e.g. applicability to all users (accessibility, internationalization), platforms, and devices (mobile, TV).

  Basically it means that we stop for a “moment”, take a deep breath, polish the feature set that we’ve been working on this far, and make sure we all agree on it, before we get back to changing the world with cool new stuff. In a software project we would call it a release branch with feature freeze.

  Now, as productive as that may sound for software – it’s not actually that exciting for a specification. Firstly, the most exciting things happen when writing new features. Secondly, development of browsers doesn’t just magically stop to get the release (REC) happening. And lastly, if we’ve done our specification work well, there should be only little work to do. Basically, it’s the unthankful work of tidying up that we’re looking at here.

  So, why am I doing it ? I am not doing this for money – I’m currently part-time contracting to Google’s accessibility team working on video accessibility and this editor work is not covered by my contract. It wasn’t possible to reconcile polishing work on a specification with the goals of my contract, which include pushing new accessibility features forward. Therefore, when invited, I decided to offer my spare time to the W3C.

  I’m giving this time under the condition that I’d only be looking at accessibility and video related sections. This is where my interest and expertise lie, and where I’m passionate to get things right. I want to make sure that we create accessibility features that will be implemented and that we polish existing video features. I want to make sure we don’t digress from implementations which continue to get updated and may follow the WHATWG spec or HTML.next or other needs.

  I am not yet completely sure what the editorship will entail. Will we look at tests, too ? Will we get involved in HTML.next ? This far we’ve been preparing for our work by setting up adequate version control repositories, building a spec creation process, discussing how to bridge to the WHATWG commits, and analysing the long list of bugs to see how to cope with them. There’s plenty of actual text editing work ahead and the team is shaping up well ! I look forward to the new experiences.