概述
FFmpeg是一套可以用来记录、转换数字音频、视频，并能将其转换成流的开源程序。它提供了录制、转换以及流化音视频的完整解决方案。
下载NDK
- 通过Android Studio下载
ndk-download.png
下载FFmpeg源码
-
通过git clone
git clone https://github.com/FFmpeg/FFmpeg.git -
到官网下载
配置configure
由于默认configure脚本编译出来的动态库版本号在文件名后缀.so之后，如：libavcodec.so.7
所以需要对configure进行修改：
# SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'
# LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
# SLIB_INSTALL_NAME='$(SLIBNAME_WITH_VERSION)'
# SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'
#
# 将上面四个变量的值改成如下：
SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB)"$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
SLIB_INSTALL_LINKS='$(SLIBNAME)'
使用android-ndk-r15c编译FFmpeg3.3.7
编写编译脚本build-android-ffmpeg.sh
#!/bin/bash
# ndk环境
export NDK=/Users/xch/debug/ndk/android-ndk-r15c
export SYSROOT=$NDK/platforms/android-21/arch-arm
export TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64
CPU=armv7-a
# 要保存动态库的目录，这里保存在源码根目录下的android/armv7-a
export PREFIX=$(pwd)/android/$CPU
ADDI_CFLAGS="-marm"
function build_android
{
echo "开始编译ffmpeg"
./configure \
--target-os=linux \
--prefix=$PREFIX \
--enable-cross-compile \
--enable-shared \
--disable-static \
--disable-doc \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-avdevice \
--disable-doc \
--disable-symver \
--cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
--arch=arm \
--sysroot=$SYSROOT \
--extra-cflags="-Os -fpic $ADDI_CFLAGS" \
--extra-ldflags="$ADDI_LDFLAGS" \
$ADDITIONAL_CONFIGURE_FLAG
make clean
make -j16
make install
echo "编译结束！"
}
build_android
编译结果：
ffmpeg-lib.png
使用android-ndk-r17b编译FFmpeg4.0.2
编译脚本build-android-ffmpeg.sh:
#!/bin/bash
# ndk环境
export NDK=/Users/xch/debug/ndk/android-ndk-r17b
export SYSROOT=$NDK/platforms/android-21/arch-arm
export TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64
CPU=armv7-a
ISYSROOT=$NDK/sysroot
ASM=$ISYSROOT/usr/include/arm-linux-androideabi
# 要保存动态库的目录，这里保存在源码根目录下的android/armv7-a
export PREFIX=$(pwd)/android/$CPU
ADDI_CFLAGS="-marm"
function build_android
{
echo "开始编译ffmpeg"
./configure \
--target-os=linux \
--prefix=$PREFIX \
--enable-cross-compile \
--enable-shared \
--disable-static \
--disable-doc \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-avdevice \
--disable-doc \
--disable-symver \
--cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
--arch=arm \
--sysroot=$SYSROOT \
--extra-cflags="-I$ASM -isysroot $ISYSROOT -D__ANDROID_API__=21 -U_FILE_OFFSET_BITS -Os -fPIC -DANDROID -Wno-deprecated -mfloat-abi=softfp -marm" \
--extra-ldflags="$ADDI_LDFLAGS" \
$ADDITIONAL_CONFIGURE_FLAG
make clean
make -j16
make install
echo "编译结束！"
}
build_android
编译过程错误处理：
错误1：变量名与宏定义冲突
compile-error1.png
解决方法：将B0修改为b0，一共4处。
错误2：
compile-error2.png
解决：将libavcodec/hevc_mvs.c中的B0改为b0。
错误3：
compile-error3.png
解决：将libavcodec/opus_pvq.c中的B0改为b0。
NOTE:
android-ndk-r16b之前版本的头文件位于{NDK_HOME}/platforms/{android-21}/{arch-arm}/usr/include，r16b及之后的版本头文件位于{NDK_HOME}/sysroot/usr/include
使用编译好的so库
Step1: 在Android Studio创建一个工程，并勾选“Include C++ support”；
build-demo-project.png
Step2: 创建一个jniLibs目录，并把编译好的头文件和.so文件都复制到该目录；
demo-project-dir.png
Step3: 配置gradle文件:
externalNativeBuild {
cmake {
cppFlags "-frtti -fexceptions"
abiFilters 'armeabi-v7a'
}
}
sourceSets.main {
jniLibs.srcDirs = ['src/main/jniLibs']
}
Step4: 编辑CMakeLists.txt文件:
cmake_minimum_required(VERSION 3.4.1)
add_library( MyFFmpeg
SHARED
src/main/cpp/native-lib.cpp )
find_library( log-lib
log )
find_library( android-lib
android )
# 设置ffmpeg库所在路径的目录
set(distribution_DIR ${CMAKE_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI})
add_library( avutil-56
SHARED
IMPORTED )
set_target_properties( avutil-56
PROPERTIES IMPORTED_LOCATION
${distribution_DIR}/libavutil-56.so)
add_library( swresample-3
SHARED
IMPORTED )
set_target_properties( swresample-3
PROPERTIES IMPORTED_LOCATION
${distribution_DIR}/libswresample-3.so)
add_library( avfilter-7
SHARED
IMPORTED )
set_target_properties( avfilter-7
PROPERTIES IMPORTED_LOCATION
${distribution_DIR}/libavfilter-7.so)
add_library( avformat-58
SHARED
IMPORTED )
set_target_properties( avformat-58
PROPERTIES IMPORTED_LOCATION
${distribution_DIR}/libavformat-58.so)
add_library( swscale-5
SHARED
IMPORTED )
set_target_properties( swscale-5
PROPERTIES IMPORTED_LOCATION
${distribution_DIR}/libswscale-5.so)
add_library( avcodec-58
SHARED
IMPORTED )
set_target_properties( avcodec-58
PROPERTIES IMPORTED_LOCATION
${distribution_DIR}/libavcodec-58.so)
# 添加ffmpeg头文件路径
include_directories(src/main/jniLibs/include)
target_link_libraries( MyFFmpeg
avcodec-58
avfilter-7
avformat-58
avutil-56
swresample-3
swscale-5
${log-lib}
${android-lib} )
Step5: 编写代码：
Java层：
public class MainActivity extends AppCompatActivity {
static {
System.loadLibrary("MyFFmpeg");
}
public native String avformatInfo();
public native String avcodecInfo();
public native String avfilterInfo();
public native String configurationInfo();
private TextView mInfoView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mInfoView = findViewById(R.id.info);
}
public void format(View view) {
mInfoView.setText(avformatInfo());
}
public void codec(View view) {
mInfoView.setText(avcodecInfo());
}
public void filter(View view) {
mInfoView.setText(avfilterInfo());
}
public void config(View view) {
mInfoView.setText(configurationInfo());
}
}
C++层：
#include <jni.h>
#include <string>
extern "C" {
#include "libavformat/avformat.h"
#include "libavcodec/avcodec.h"
#include "libavutil/avutil.h"
#include "libavfilter/avfilter.h"
JNIEXPORT jstring JNICALL
Java_com_github_xch168_ffmpegdemo_MainActivity_avformatInfo(JNIEnv *env, jobject instance) {
char info[40000] = { 0 };
AVInputFormat *if_temp = av_iformat_next(NULL);
AVOutputFormat *of_temp = av_oformat_next(NULL);
//Input
while (if_temp != NULL){
sprintf(info, "%s[In ][%10s]\n", info, if_temp->name);
if_temp = if_temp->next;
}
//Output
while (of_temp != NULL) {
sprintf(info, "%s[Out][%10s]\n", info, of_temp->name);
of_temp = of_temp->next;
}
return env->NewStringUTF(info);
}
JNIEXPORT jstring JNICALL
Java_com_github_xch168_ffmpegdemo_MainActivity_avcodecInfo(JNIEnv *env, jobject instance) {
char info[40000] = { 0 };
AVCodec *c_temp = av_codec_next(NULL);
while (c_temp!=NULL) {
if (c_temp->decode!=NULL){
sprintf(info, "%s[Dec]", info);
}
else{
sprintf(info, "%s[Enc]", info);
}
switch (c_temp->type) {
case AVMEDIA_TYPE_VIDEO:
sprintf(info, "%s[Video]", info);
break;
case AVMEDIA_TYPE_AUDIO:
sprintf(info, "%s[Audio]", info);
break;
default:
sprintf(info, "%s[Other]", info);
break;
}
sprintf(info, "%s[%10s]\n", info, c_temp->name);
c_temp=c_temp->next;
}
return env->NewStringUTF(info);
}
JNIEXPORT jstring JNICALL
Java_com_github_xch168_ffmpegdemo_MainActivity_avfilterInfo(JNIEnv *env, jobject instance) {
char info[40000] = { 0 };
AVFilter *f_temp = (AVFilter *)avfilter_next(NULL);
while (f_temp != NULL){
sprintf(info, "%s[%10s]\n", info, f_temp->name);
f_temp = f_temp->next;
}
return env->NewStringUTF(info);
}
JNIEXPORT jstring JNICALL
Java_com_github_xch168_ffmpegdemo_MainActivity_configurationInfo(JNIEnv *env, jobject instance) {
char info[10000] = {0};
sprintf(info, "%s\n", avcodec_configuration());
return env->NewStringUTF(info);
}
}
运行结果：
run-result.gif
参考链接
- Android 基于ffmpeg开发简易播放器 - NDK交叉编译ffmpeg
- 在Mac下使用NDK编译FFmpeg3.3.4
- Ubuntu编译Android版本FFmpeg
- Unified Headers
- Android最简单的基于FFmpeg的例子(一)---编译FFmpeg类库
- Android最简单的基于FFmpeg的例子(二)---测试编译好的SO库
编码前线.jpg
