交叉编译多平台 FFmpeg 库并提取视频帧
转 https://www.cnblogs.com/leviatan/p/11142579.html
本文档适用于 x86 平台编译 armeabi、armeabi-v7a、arm64-v8a、x86、x86_64 平台的 ffmpeg 运行库
开发环境
编译环境: Ubuntu 1810 x64
开发环境: Windows 10
IDE: Android Studio 3.4.1
Android: 7.1
FFmpeg: 3.4.6
编译流程
下载 FFmpeg 源码: Download FFmpeg
解压后进入源码包，创建 build.sh 文件，并赋予执行权限
tar zxvf ffmpeg-3.4.6.tar.gz
cd ffmpeg-3.4.6
touch build.sh
chmod +x build.sh将以下脚本写入 build.sh
NDK_PATH 建议下载 Revision 15C 版本
根据实际情况修改 NDK_PATH，TOOLCHAIN_VERSION 及 ANDROID_VERSION
#!/bin/sh
MY_LIBS_NAME=ffmpeg-3.4.6
# 编译产生的中间件目录
MY_BUILD_DIR=binary
# NDK 目录
NDK_PATH=/usr/android-sdk-linux/android-ndk-r15c
# 编译平台
BUILD_PLATFORM=linux-x86_64
# NDK 中交叉编译工具版本
TOOLCHAIN_VERSION=4.9
# Android API Level
ANDROID_VERSION=26
ANDROID_ARMV5_CFLAGS="-march=armv5te"
ANDROID_ARMV7_CFLAGS="-march=armv7-a -mfloat-abi=softfp -mfpu=neon"
ANDROID_ARMV8_CFLAGS="-march=armv8-a"
ANDROID_X86_CFLAGS="-march=i686 -mtune=intel -mssse3 -mfpmath=sse -m32"
ANDROID_X86_64_CFLAGS="-march=x86-64 -msse4.2 -mpopcnt -m64 -mtune=intel"
# params($1: arch, $2: arch_abi, $3: host, $4: cross_prefix, $5: cflags)
build_bin() {
echo "------------------- Start build $2 -------------------------"
ARCH=$1 # arm arm64 x86 x86_64
ANDROID_ARCH_ABI=$2 # armeabi armeabi-v7a x86 mips
PREFIX=$(pwd)/dist/${MY_LIBS_NAME}/${ANDROID_ARCH_ABI}/
HOST=$3
SYSROOT=${NDK_PATH}/platforms/android-${ANDROID_VERSION}/arch-${ARCH}
CFALGS=$5
TOOLCHAIN=${NDK_PATH}/toolchains/${HOST}-${TOOLCHAIN_VERSION}/prebuilt/${BUILD_PLATFORM}
CROSS_PREFIX=${TOOLCHAIN}/bin/$4-
# build 中间件
mkdir -p ${MY_BUILD_DIR}/${ANDROID_ARCH_ABI}
BUILD_DIR=./${MY_BUILD_DIR}/${ANDROID_ARCH_ABI}
echo "pwd==$(pwd)"
echo "ARCH==${ARCH}"
echo "PREFIX==${PREFIX}"
echo "HOST==${HOST}"
echo "SYSROOT=${SYSROOT}"
echo "CFALGS=$5"
echo "CFALGS=${CFALGS}"
echo "TOOLCHAIN==${TOOLCHAIN}"
echo "CROSS_PREFIX=${CROSS_PREFIX}"
mkdir -p ${BUILD_DIR}
cd ${BUILD_DIR}
sh ../../configure \
--prefix=${PREFIX} \
--target-os=linux \
--arch=${ARCH} \
--sysroot=$SYSROOT \
--enable-cross-compile \
--cross-prefix=${CROSS_PREFIX} \
--extra-cflags="$CFALGS -Os -fPIC -DANDROID -Wfatal-errors -Wno-deprecated" \
--extra-cxxflags="-D__thumb__ -fexceptions -frtti" \
--extra-ldflags="-L${SYSROOT}/usr/lib" \
--enable-shared \
--enable-asm \
--enable-neon \
--disable-encoders \
--enable-encoder=aac \
--enable-encoder=mjpeg \
--enable-encoder=png \
--disable-decoders \
--enable-decoder=aac \
--enable-decoder=aac_latm \
--enable-decoder=h264 \
--enable-decoder=mpeg4 \
--enable-decoder=mjpeg \
--enable-decoder=png \
--disable-demuxers \
--enable-demuxer=image2 \
--enable-demuxer=h264 \
--enable-demuxer=aac \
--disable-parsers \
--enable-parser=aac \
--enable-parser=ac3 \
--enable-parser=h264 \
--enable-gpl \
--disable-doc \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-symver \
--disable-debug \
--enable-small
make clean
make
make install
cd ../../
echo "------------------- $2 Build finish -------------------------"
}
# build for armeabi
#build_bin arm armeabi arm-linux-androideabi arm-linux-androideabi "$ANDROID_ARMV5_CFLAGS"
# build for armeabi-v7a
#build_bin arm armeabi-v7a arm-linux-androideabi arm-linux-androideabi "$ANDROID_ARMV7_CFLAGS"
# build for arm64-v8a
build_bin arm64 arm64-v8a aarch64-linux-android aarch64-linux-android "$ANDROID_ARMV8_CFLAGS"
# build for x86
#build_bin x86 x86 x86 i686-linux-android "$ANDROID_X86_CFLAGS"
# build for x86_64
#build_bin x86_64 x86_64 x86_64 x86_64-linux-android "$ANDROID_X86_64_CFLAGS"根据需要选择脚本最后的编译命令，直接运行脚本即可自动编译
编译成功后目录结构
ffmpeg-3.4.6
├─ binary # 编译产生的中间件
├─ build.sh # 编译脚本
├─ Changelog
├─ compat
├─ configure
├─ CONTRIBUTING.md
├─ COPYING.GPLv2
├─ COPYING.GPLv3
├─ COPYING.LGPLv2.1
├─ COPYING.LGPLv3
├─ CREDITS
├─ dist # 编译输出的库和头文件目录
│ └─ ffmpeg-3.4.6 # 该文件夹名由 MY_LIBS_NAME 指定
│ └─ arm64-v8a # 与编译的目标平台 ABI 名称相同
│ ├─ bin
│ ├─ include # 头文件目录
│ │ ├─ libavcodec
│ │ ├─ libavdevice
│ │ ├─ libavfilter
│ │ ├─ libavformat
│ │ ├─ libavutil
│ │ ├─ libpostproc
│ │ ├─ libswresample
│ │ └─ libswscale
│ ├─ lib # 库目录，包含动态库和静态库
│ │ ├─ libavcodec-57.so
│ │ ├─ libavcodec.a
│ │ ├─ libavcodec.so -> libavcodec-57.so
│ │ ├─ libavdevice-57.so
│ │ ├─ libavdevice.a
│ │ ├─ libavdevice.so -> libavdevice-57.so
│ │ ├─ libavfilter-6.so
│ │ ├─ libavfilter.a
│ │ ├─ libavfilter.so -> libavfilter-6.so
│ │ ├─ libavformat-57.so
│ │ ├─ libavformat.a
│ │ ├─ libavformat.so -> libavformat-57.so
│ │ ├─ libavutil-55.so
│ │ ├─ libavutil.a
│ │ ├─ libavutil.so -> libavutil-55.so
│ │ ├─ libpostproc-54.so
│ │ ├─ libpostproc.a
│ │ ├─ libpostproc.so -> libpostproc-54.so
│ │ ├─ libswresample-2.so
│ │ ├─ libswresample.a
│ │ ├─ libswresample.so -> libswresample-2.so
│ │ ├─ libswscale-4.so
│ │ ├─ libswscale.a
│ │ ├─ libswscale.so -> libswscale-4.so
│ │ └─ pkgconfig
│ └─ share
├─ doc
├─ ffbuild
├─ fftools
├─ INSTALL.md
├─ libavcodec
├─ libavdevice
├─ libavfilter
├─ libavformat
├─ libavresample
├─ libavutil
├─ libpostproc
├─ libswresample
├─ libswscale
├─ LICENSE.md
├─ MAINTAINERS
├─ Makefile
├─ presets
├─ README.md
├─ RELEASE
├─ RELEASE_NOTES
├─ tests
├─ tools
└─ VERSION将运行库导入到项目中
目录结构
ffmpegtest
├─ app
│ ├─ build
│ ├─ libs
│ └─ src
│ ├─ androidTest
│ ├─ main
│ │ ├─ java
│ │ │ └─ com
│ │ │ └─ example
│ │ │ └─ ffmpegtest
│ │ │ MainActivity.java
│ │ ├─ jni # C/C++ 源码目录
│ │ │ └─ include # 需要导入的头文件
│ │ │ ├─ libavcodec
│ │ │ ├─ libavdevice
│ │ │ ├─ libavfilter
│ │ │ ├─ libavformat
│ │ │ ├─ libavutil
│ │ │ ├─ libpostproc
│ │ │ ├─ libswresample
│ │ │ └─ libswscale
│ │ ├─ jniLibs # JNI 需要调用的运行库
│ │ │ └─ arm64-v8a # 对应 ABI 版本建立文件夹
│ │ │ ├─ libavcodec-57.so
│ │ │ ├─ libavdevice-57.so
│ │ │ ├─ libavfilter-6.so
│ │ │ ├─ libavformat-57.so
│ │ │ ├─ libavutil-55.so
│ │ │ ├─ libpostproc-54.so
│ │ │ ├─ libswresample-2.so
│ │ │ ├─ libswscale-4.so
│ │ │ └─ libswscale-4.so
│ │ └─ res
│ └─ test
└─ gradleCMakeLists.txt 添加以下配置
include_directories(${PROJECT_SOURCE_DIR}/src/main/jni/include)
add_library(ffmpegTest
SHARED
src/main/jni/ffmpegTest.cpp )
add_library(avcodec-57 SHARED IMPORTED)
set_target_properties(avcodec-57
PROPERTIES
IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libavcodec-57.so )
add_library(avfilter-6 SHARED IMPORTED)
set_target_properties(avfilter-6
PROPERTIES
IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libavfilter-6.so )
add_library(avformat-57 SHARED IMPORTED)
set_target_properties(avformat-57
PROPERTIES
IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libavformat-57.so )
add_library(avutil-55 SHARED IMPORTED)
set_target_properties(avutil-55
PROPERTIES
IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libavutil-55.so )
add_library(postproc-54 SHARED IMPORTED)
set_target_properties(postproc-54
PROPERTIES
IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libpostproc-54.so )
add_library(avdevice-57 SHARED IMPORTED)
set_target_properties(avdevice-57
PROPERTIES
IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libavdevice-57.so )
add_library(swscale-4 SHARED IMPORTED)
set_target_properties(swscale-4
PROPERTIES
IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libswscale-4.so )
add_library(swresample-2 SHARED IMPORTED)
set_target_properties(swresample-2
PROPERTIES
IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libswresample-2.so )
target_link_libraries(ffmpegTest
${log-lib}
avcodec-57 avfilter-6 avformat-57 avutil-55 postproc-54 avdevice-57 swscale-4 swresample-2)提取视频帧并保存为图片
#include <jni.h>
#include <android/log.h>
extern "C" {
#include <libavformat/avformat.h>
}
#define DEBUG
#ifdef DEBUG
#define LOG "ffmpegLOG"
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, LOG, __VA_ARGS__)
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, LOG, __VA_ARGS__)
#define LOGW(...) __android_log_print(ANDROID_LOG_WARN, LOG, __VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, LOG, __VA_ARGS__)
#define LOGF(...) __android_log_print(ANDROID_LOG_FATAL, LOG, __VA_ARGS__)
#else
#define LOG
#define LOGD(...)
#define LOGI(...)
#define LOGW(...)
#define LOGE(...)
#define LOGF(...)
#endif
int writeJPEG(AVFrame* frame, int width, int height, char* output_ath, int image_index);
extern "C"
JNIEXPORT jint JNICALL
Java_com_example_ffmpegtest_MainActivity_videoFrame(JNIEnv *env, jobject instance,
jstring filePath_, jstring outputPath_) {
const char *filePath = env->GetStringUTFChars(filePath_, 0);
const char *outputPath = env->GetStringUTFChars(outputPath_, 0);
LOGE("======================= ffmpeg start =======================");
clock_t time_start, time_finish;
double total_time;
time_start = clock();
// 注册所有模块
av_register_all();
AVFormatContext *formatContext = nullptr;
int ret = 0;
LOGD("Video path: [%s]", filePath);
// 打开媒体
ret = avformat_open_input(&formatContext, filePath, nullptr, nullptr);
if (ret < 0) {
LOGE("Cannot open file, error code: [%d]", ret);
return -1;
}
// 获取媒体信息
ret = avformat_find_stream_info(formatContext, nullptr);
if (ret < 0) {
LOGE("Cannot find stream, error code: [%d]", ret);
return -1;
}
int video_index = -1;
// 遍历媒体流
for (int i = 0; i < formatContext->nb_streams; i++) {
if (formatContext->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
video_index = i;
break;
}
}
if (video_index == -1) {
LOGE("Cannot find video stream");
return -1;
}
// 找出一个有效码流的 AVCodecID，根据标准寻找对应的解码器
AVCodecContext *codecContext = formatContext->streams[video_index]->codec;
enum AVCodecID codecId = codecContext->codec_id;
AVCodec *codec = avcodec_find_decoder(codecId);
if(!codec){
LOGE("Cannot find decoder");
return -1;
}
// 初始化解码器
ret = avcodec_open2(codecContext, codec, nullptr);
if (ret < 0) {
LOGE("Cannot open decoder, error code: [%d]", ret);
return -1;
}
// 分配内存
AVPacket *packet = av_packet_alloc();
AVFrame *frame = av_frame_alloc();
int image_index = 0;
// 当剩余帧数大于 0 时
while (av_read_frame(formatContext, packet) >= 0) {
if (packet && packet->stream_index == video_index) {
int gotFrame = 0;
// 将 AVPacket 中的数据解码为原始数据（YUV、RGB 以及 PCM），存储在 AVFrame 上
avcodec_decode_video2(codecContext, frame, &gotFrame, packet);
if (gotFrame) {
image_index++;
// 将视频帧保存在本地
ret = writeJPEG(frame, codecContext->width, codecContext->height, (char*)outputPath, image_index);
if(ret == 0){
LOGI("Save frame in %s and rename to video_frame_%d.jpg", outputPath, image_index);
}
}
}
}
time_finish = clock();
total_time = (double)(time_finish - time_start);
LOGE("Total time: [%f]ms --- ffmpeg", total_time);
LOGE("======================= ffmpeg finish =======================");
env->ReleaseStringUTFChars(filePath_, filePath);
env->ReleaseStringUTFChars(outputPath_, outputPath);
av_frame_free(&frame);
avcodec_close(codecContext);
avformat_free_context(formatContext);
return 0;
}
int writeJPEG(AVFrame *frame, int width, int height,char* output_path, int image_index) {
char *out_file;
sprintf(out_file, "%s/video_frame_%d.jpg", output_path, image_index);
// 分配内存空间
AVFormatContext *formatContext = avformat_alloc_context();
// 初始化 AVFormatContext 结构体
avformat_alloc_output_context2(&formatContext, nullptr, "singlejpeg", out_file);
// 指定图片格式
formatContext->oformat = av_guess_format("mjpeg", nullptr, nullptr);
// 打开(创建?)要写入的文件
if (avio_open(&formatContext->pb, out_file, AVIO_FLAG_READ_WRITE) < 0) {
LOGE("Open file failed---write JPEG");
return -1;
}
// 创建流通道，例如 Video - H.264, Audio - AAC
AVStream *stream = avformat_new_stream(formatContext, nullptr);
if (stream == nullptr) {
LOGE("Create stream failed---write JPEG");
return -1;
}
AVCodecContext *codecContext = stream->codec;
// 保存文件头信息（帧信息）
codecContext->codec_id = formatContext->oformat->video_codec;
codecContext->codec_type = AVMEDIA_TYPE_VIDEO;
codecContext->pix_fmt = AV_PIX_FMT_YUVJ420P;
codecContext->height = height;
codecContext->width = width;
codecContext->time_base.num = 1;
codecContext->time_base.den = 25;
// 寻找解码器
AVCodec* codec = avcodec_find_encoder(codecContext->codec_id);
if (!codec) {
LOGE("Cannot find encoder---write JPEG");
return -1;
}
// 初始化解码器
if (avcodec_open2(codecContext, codec, nullptr) < 0) {
LOGE("Cannot open encoder---write JPEG");
return -1;
}
// 将文件头保存到 codecpar 中
avcodec_parameters_from_context(stream->codecpar, codecContext);
// 写入头数据
avformat_write_header(formatContext, nullptr);
// 创建并初始化 ACPacket 内存空间
int size = codecContext->width * codecContext->height;
AVPacket *writePacket = av_packet_alloc();
av_new_packet(writePacket, size * 3);
int got_image = 0;
// 调用编码器，编码为指定格式
int result = avcodec_encode_video2(codecContext, writePacket, frame, &got_image);
if (result < 0) {
LOGE("Encode failed---write JPEG");
return -1;
}
if (got_image == 1) {
// 输出一帧数据
av_write_frame(formatContext, writePacket);
}
// 释放内存
av_free_packet(writePacket);
// 写文件尾
av_write_trailer(formatContext);
// 将 AVFrame 归零
if (frame) {
av_frame_unref(frame);
}
// 关闭文件
avio_close(formatContext->pb);
// 释放内存
avformat_free_context(formatContext);
return 0;
}在 Activity 中调用
public class MainActivity extends AppCompatActivity {
// 导入运行库
static {
System.loadLibrary("ffmpegTest");
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 获取存储设备路径
String storagePath = Environment.getExternalStorageDirectory().getPath();
File videoPath = new File(storagePath + "/Download/testVideo.mp4");
videoFrame(videoPath.toString(), storagePath + "/Download/video_frames/");
}
}
// 实例化运行库中的方法
public native int videoFrame(String filePath, String outputPath);