NDK R21 compiles ffmpeg 4.2.2 (x86, x86_64, armv7, armv8)

1. compile FFmpeg

Get ready Ununtu、ndk r21（linux）、FFmpeg.

Prepare to compile the script , There are two , One of them is dedicated to armv7 Of .

armv7

#!/bin/bash

API=21
#armv7-a
ARCH=armv7 

PREFIX=./SO/$ARCH

TOOLCHAIN=/home/qwe/android-ndk-r21/toolchains/llvm/prebuilt/linux-x86_64

build()
{
    
./configure \
--prefix=$PREFIX \
--disable-static \
--enable-shared \
--enable-small \
--enable-gpl \
--disable-doc \
--disable-programs \
--disable-avdevice \
--enable-cross-compile \
--target-os=android \
--arch=$ARCH \
--cc=$TOOLCHAIN/bin/armv7a-linux-androideabi$API-clang \
--cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- 

make clean
make -j4
make install

}

build

arm64 x86 x86_64

#!/bin/bash

API=21
#arm64 x86 x86_64  Corresponding  aarch64 i686 x86_64 
ARCH=arm64
ARCH2=aarch64    

PREFIX=./SO/$ARCH

TOOLCHAIN=/home/qwe/android-ndk-r21/toolchains/llvm/prebuilt/linux-x86_64

build()
{
    
./configure \
--prefix=$PREFIX \
--disable-static \
--enable-shared \
--enable-small \
--disable-doc \
--disable-programs \
--disable-avdevice \
--enable-cross-compile \
--target-os=android \
--arch=$ARCH \
--cc=$TOOLCHAIN/bin/$ARCH2-linux-android$API-clang \
--cross-prefix=$TOOLCHAIN/bin/$ARCH2-linux-android- 

make clean
make -j4
make install

}

build

stay FFmpeg Run the script from the root directory of . The initial run will prompt the lack of software , Just follow the prompts to install .

[email protected]:~/FFmpeg-n4.2.2$ sudo su
[sudo] qwe  Password ： 
[email protected]:/home/qwe/FFmpeg-n4.2.2# ./build3.sh 

2. Use FFmpeg Of so library

android studio Create project

take so Copy the file to the following directory .include yes FFmpeg Of .h file ,x86、x86_64、armv7、armv8 Generated .h Same .

edit build.gradle(:app)

android {
    
    .....
    sourceSets {
    
        main {
    //jniLibs
            jniLibs.srcDirs = ['src/main/libs']
        }
    }
}

edit cmakeList.txt

cmake_minimum_required(VERSION 3.4.1)

# Set up two directories ,${
    ANDROID_ABI} It will change according to the equipment 
set(DIR ${
    PROJECT_SOURCE_DIR}/../libs/${
    ANDROID_ABI})
set(DIR2 ${
    PROJECT_SOURCE_DIR}/../libs)
# Appoint h File directory , The compilation process needs to find .h file 
include_directories(${
    DIR2}/include)

add_library( # Sets the name of the library.
        native-lib

        # Sets the library as a shared library.
        SHARED

        # Provides a relative path to your source file(s).
        native-lib.cpp)

# Import FFmpeg The library of 
add_library(libavcodec SHARED IMPORTED)
#so The location of the file 
set_target_properties(libavcodec
        PROPERTIES IMPORTED_LOCATION
        ${
    DIR}/libavcodec.so)


add_library(libavfilter SHARED IMPORTED)
set_target_properties(libavfilter
        PROPERTIES IMPORTED_LOCATION
        ${
    DIR}/libavfilter.so)

add_library(libavformat SHARED IMPORTED)
set_target_properties(libavformat
        PROPERTIES IMPORTED_LOCATION
        ${
    DIR}/libavformat.so)

add_library(libavutil SHARED IMPORTED)
set_target_properties(libavutil
        PROPERTIES IMPORTED_LOCATION
        ${
    DIR}/libavutil.so)

add_library(libswresample SHARED IMPORTED)
set_target_properties(libswresample
        PROPERTIES IMPORTED_LOCATION
        ${
    DIR}/libswresample.so)

add_library(libswscale SHARED IMPORTED)
set_target_properties(libswscale
        PROPERTIES IMPORTED_LOCATION
        ${
    DIR}/libswscale.so)

find_library( # Sets the name of the path variable.
        log-lib

        log)

# Connection Library 
target_link_libraries( # Specifies the target library.
        native-lib

        # Links the target library to the log library
        # included in the NDK.
        ${
    log-lib}
        libavfilter
        libavformat
        libswresample
        libswscale
        libavutil
        libavcodec)

change native-lib.cpp Medium stringFromJNI Method

#include <jni.h>
#include <string>

extern  "C"{
    
#include "libavcodec/avcodec.h"
}


extern "C" JNIEXPORT jstring JNICALL
Java_cn_study_testffmpeg_MainActivity_stringFromJNI(
        JNIEnv *env,
        jobject /* this */) {
    
    std::string hello = avcodec_configuration();
    return env->NewStringUTF(hello.c_str());
}

Running effect