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• Undefined Reference - ffmpeg on android ndk

  28 décembre 2012, par Gabriel Simões

  I´ve spent many hours trying to figure out why I still get "undefined reference" when trying to link to ffmpeg.
  I´ve already read most if not all posts and sites about the subject, so I think I´m missing something little here and I hope you can help me.

  What I have :

  I´m using windows 7 + cygwin + crystax r4.
  I´ve compiled FFMPEG using RockPlayer's ffmpeg source plus some modifications I did (only to include / exclude demuxes, decoders, encoders, ...)
  After compiling, I get :

  • a new folder named armv5te, which includes :
  • a folder named "include" with all folders for each libs' .h
  • a folder named "lib" which includes all libs' .a
  • a shared library named libffmpeg.so (checked soname and it is libffmpeg)

  The shared library isn´t also placed on project/lib/armeabi/libffmpeg.so

  After compiling I tried to compile my project and link it. While my .cpp compiles ok, I get many undefined references.

  here is my build script :

  NDK=/cygdrive/c/Gabriel/Desenvolvimento/SDKs/Android/android-ndk-r4-crystax
  
  PLATFORM=$NDK/build/platforms/android-8/arch-arm/
  
  PREBUILT=$NDK/build/prebuilt/windows/arm-eabi-4.4.0
  
  
  
  
  
  function build_one
  
  {
  
  
  
  ./configure --target-os=linux \
  
      --prefix=$PREFIX \
  
      --enable-cross-compile \
  
      --extra-libs="-lgcc" \
  
      --arch=arm \
  
      --cc=$PREBUILT/bin/arm-eabi-gcc \
  
      --cross-prefix=$PREBUILT/bin/arm-eabi- \
  
      --nm=$PREBUILT/bin/arm-eabi-nm \
  
      --sysroot=$PLATFORM \
  
      --extra-cflags=" -O2 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 -Dipv6mr_interface=ipv6mr_ifindex -fasm -Wno-psabi -fno-short-enums  -fno-strict-aliasing -finline-limit=300 $OPTIMIZE_CFLAGS " \
  
      --disable-shared \
  
      --enable-static \
  
      --extra-ldflags="-Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -nostdlib -lc -lm -ldl -llog" \
  
      --disable-stripping \
  
      --disable-debug \
  
      --disable-symver \
  
      --disable-ffprobe \
  
      --disable-devices \
  
      --disable-avfilter \
  
      --disable-swscale \
  
      --disable-ffplay \
  
      --disable-ffserver \
  
      --disable-network \
  
          (many more ...)
  
      --enable-asm \
  
      $ADDITIONAL_CONFIGURE_FLAG
  
  
  
  #make clean
  
  make  -j4 install
  
  
  
  $PREBUILT/bin/arm-eabi-ar d libavcodec/libavcodec.a inverse.o
  
  
  
  $PREBUILT/bin/arm-eabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a  -lc -lm -lz -ldl -llog  --warn-once  --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-eabi/4.4.0/libgcc.a
  
  
  
  }
  
  
  
  #arm v5
  
  CPU=armv5te
  
  OPTIMIZE_CFLAGS="-marm -march=$CPU"
  
  PREFIX=./android/$CPU 
  
  ADDITIONAL_CONFIGURE_FLAG=
  
  build_one

  Here is my android.mk :

  LOCAL_PATH := $(call my-dir)
  
  
  
  #declare the prebuilt library
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE := ffmpeg-prebuilt
  
  LOCAL_SRC_FILES := $(LOCAL_PATH)/ffmpeg/android/armv5te/libffmpeg.so
  
  LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/ffmpeg/android/armv5te/include
  
  LOCAL_PRELINK_MODULE := true 
  
  include $(PREBUILT_SHARED_LIBRARY)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE    := audiocodec
  
  LOCAL_SRC_FILES := ffmpeg_audio.cpp
  
  LOCAL_SHARED_LIBRARY := libffmpeg
  
  LOCAL_C_INCLUDES := $(LOCAL_PATH)/ffmpeg/android/armv5te/include
  
  LOCAL_LDLIBS    := -llog -ljnigraphics -lz -lm $(LOCAL_PATH)/ffmpeg/android/armv5te/libffmpeg.so
  
  include $(BUILD_SHARED_LIBRARY)

  The result :

  Compile++ thumb: audiocodec <= /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFM
  
  PEG/jni/ffmpeg_audio.cpp
  
  SharedLibrary  : libaudiocodec.so
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/obj/local/armeabi/objs/audi
  
  ocodec/ffmpeg_audio.o: In function `Java_gabriel_audioslower_pro_ffmpegDecoder_r
  
  eadSamples':
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:172: u
  
  ndefined reference to `avcodec_decode_audio3(AVCodecContext*, short*, int*, AVPa
  
  cket*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:178: u
  
  ndefined reference to `av_read_frame(AVFormatContext*, AVPacket*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/obj/local/armeabi/objs/audi
  
  ocodec/ffmpeg_audio.o: In function `Java_gabriel_audioslower_pro_ffmpegDecoder_s
  
  eekToPosMS':
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:147: u
  
  ndefined reference to `av_rescale_q(long long, AVRational, AVRational)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:150: u
  
  ndefined reference to `av_seek_frame(AVFormatContext*, int, long long, int)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:151: u
  
  ndefined reference to `avcodec_flush_buffers(AVCodecContext*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:152: u
  
  ndefined reference to `av_read_frame(AVFormatContext*, AVPacket*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/obj/local/armeabi/objs/audi
  
  ocodec/ffmpeg_audio.o: In function `Java_gabriel_audioslower_pro_ffmpegDecoder_c
  
  loseFile':
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:82: un
  
  defined reference to `avcodec_close(AVCodecContext*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:83: un
  
  defined reference to `av_free(void*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:84: un
  
  defined reference to `av_close_input_file(AVFormatContext*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/obj/local/armeabi/objs/audi
  
  ocodec/ffmpeg_audio.o: In function `Java_gabriel_audioslower_pro_ffmpegDecoder_o
  
  penAudioFile':
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:37: un
  
  defined reference to `av_open_input_file(AVFormatContext**, char const*, AVInput
  
  Format*, int, AVFormatParameters*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:44: un
  
  defined reference to `av_find_stream_info(AVFormatContext*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:52: un
  
  defined reference to `avcodec_find_decoder(CodecID)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:60: un
  
  defined reference to `avcodec_open(AVCodecContext*, AVCodec*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:67: un
  
  defined reference to `av_malloc(unsigned int)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:70: un
  
  defined reference to `av_read_frame(AVFormatContext*, AVPacket*)'
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/obj/local/armeabi/objs/audi
  
  ocodec/ffmpeg_audio.o: In function `JNI_OnLoad':
  
  /cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/jni/ffmpeg_audio.cpp:25: un
  
  defined reference to `av_register_all()'
  
  collect2: ld returned 1 exit status
  
  make: *** [/cygdrive/c/Gabriel/Desenvolvimento/Workspace/FFMPEG/obj/local/armeab
  
  i/libaudiocodec.so] Error 1

  Something interesting is that some functions from ffmpeg, as av_register_all(), do now show up on the list of undefined references.

  Any ideas on what I can do to fix it ? I´ve spent 3 days trying to make things work ..
  Thanks !

• Splicing two gifs together every other frame using ffmpeg

  30 juillet 2021, par Alexwall

  I have two gifs I want to be combined together in an odd fashion.

  


  If I have gif1.gif and gif2.gif i want one frame of gif2.gif inserted every other frame of gif1.gif, in a sort of zipper like way if that makes sense.

  


  Is this feasible ? Is ffmpeg maybe not the right software to use for this ?

  


• Texai Remote Presence System Using VP8 Video

  19 novembre 2010, par noreply@blogger.com (John Luther)

  Guest blogger Josh Tyler is a member of the Texai team at Willow Garage.

  Willow Garage is busy building the next version of its Texai remote presence platform with VP8, the video codec used in WebM.

  In short, Texai is a two-way videoconferencing app on a tele-operated robotic platform (for more details, see the piece about Texai in the New York Times). Video and audio quality are critical to providing the best user experience on Texai. We’ve evaluated several video codecs and found VP8’s image quality, low latency and tolerance to packet loss far better than anything else we tested.

  The video below shows VP8 running on one of our systems.

  (If you have a WebM-enabled browser and are enrolled in the YouTube HTML5 beta the video will play in WebM HTML5, otherwise it will play in Flash Player.)

  We’re also looking for help ! If you’re interested in helping us create an incredible, high-fidelity user experience, either by joining our team, partnering on development, or by being added to our early customer interest list, please email us at texai-info@willowgarage.com.