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• MLT framework windows build melt failed to load avformat

  22 juillet 2015, par Philip

  I build mlt framework on windows following the official guide http://www.mltframework.org/bin/view/MLT/WindowsBuild and the solution of Error building MLT framework on Windows for the errors.

  But when I call the command melt it doesn’t work correctly. (melt noise does work)

  Using melt -query "video_codecs" I get # No video codecs - failed to load avformat consumer.

  So it cannot load ffmpeg. Is there a problem with the compilation or is something related to Windows ?

• failed to set frame number in opencv in cpp

  28 février 2018, par Madhu Nadendla

  I am trying to set frame position of opened videofile using OpenCV in C++ but it returns 0.

  solution 1

  bool success = capture.set(CV_CAP_PROP_POS_FRAMES, noFrame);
  
  
  
  double frameRate = capture.get(CV_CAP_PROP_FPS);

• clang++ : error : linker command failed with exit code 1 (use -v to see invocation) in cpp with ffmpeg

  6 avril 2020, par Pradeep Simba

  clang++: error: linker command failed with exit code 1 (use -v to see invocation)


  



  I saw this link and link2. But, it not done.

  



  My jni folder :

  



  

  



  Android.mk file

  



  LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_C_INCLUDES += ./include
LOCAL_MODULE     := native-lib
LOCAL_CFLAGS := -DSTDC_HEADERS -std=c99
LOCAL_CFLAGS := -Wno-pointer-sign
LOCAL_ARM_MODE := arm
APP_OPTIM := release
LOCAL_SRC_FILES  := \
./native-lib.cpp
LOCAL_LDLIBS := -llog
include $(BUILD_SHARED_LIBRARY)


  



  native-lib.cpp file

  



  #include &#xA;#include <string>&#xA;&#xA;extern "C"&#xA;{&#xA;#include "libavcodec/avcodec.h"&#xA;#include "libavformat/avformat.h"&#xA;#include "libavutil/opt.h"&#xA;}&#xA;&#xA;extern "C" JNIEXPORT jstring JNICALL&#xA;Java_com_example_m_MainActivity_stringFromJNI(&#xA;JNIEnv* env,&#xA;jobject /* this */) {&#xA;std::string hello = "Hello from C&#x2B;&#x2B;";&#xA;av_register_all();&#xA;return env->NewStringUTF(hello.c_str());&#xA;}&#xA;</string>

  



  When I build ndk this error occurs.

  



  D:\Github\n>ndk-build
Android NDK: APP_PLATFORM not set. Defaulting to minimum supported version android-16.
[arm64-v8a] Compile++      : native-lib <= native-lib.cpp
[arm64-v8a] SharedLibrary  : libnative-lib.so
./obj/local/arm64-v8a/objs/native-lib/./libmp3lame/native-lib.o: In function `Java_com_example_m_MainActivity_stringFromJNI':
D:\Github\n/jni/./libmp3lame/native-lib.cpp:16: undefined reference to `av_register_all'
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [D:/install/sdk/ndk/21.0.6113669/build//../build/core/build-binary.mk:725: obj/local/arm64-v8a/libnative-lib.so] Error 1

D:\Github\n>ndk-build -v
GNU Make 4.2.1
Built for x86_64-w64-mingw32
Copyright (C) 1988-2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later /gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

D:\Github\n>


  



  why it comes like this native-lib.cpp:16: undefined reference av_register_all ?

  



  I added all the required libs in my jni folder but, why this error and this native-lib.cpp:16: undefined reference av_register_all comes ?
How can I solve this ?