前言
前面我学了编译FFmpeg的Android库,写了一个命令行使用FFmpeg的Android Demo,C文件都在虚拟机实现,然后ndk编译成so库,再导入Android studio使用,Android代码中没有C/C++文件,很纯净的样子。但是,在虚拟机写C代码的时候,没有自动补全功能,很不方便。所以这次用Cmake编译JNI,直接在Android studio中使用代码补全功能!
1、编译Android版FFmpeg并移植到Android studio中
1.1、编译FFmpeg的Android库
见Android FFmpeg JNI开发入门_编译不同ABI的so库
1.2、创建一个支持C++的Android项目
把红框的选项都勾选上
生成之后的项目目录
1.2、将so库移植到Android项目中
在libs目录下新建对应ABI的文件夹,比如armeabi-v7a,然后将编译生成的对应ABI的so库拷贝进去;
再将头文件拷贝进去,就是生成的include目录;
然后修改app的build.gradle文件如下;
再修改CmakeLists.txt文件,指定依赖库:
# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html
# Sets the minimum version of CMake required to build the native library.
cmake_minimum_required(VERSION 3.4.1)
# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.
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).
src/main/cpp/native-lib.cpp)
# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.
find_library( # Sets the name of the path variable.
log-lib
# Specifies the name of the NDK library that
# you want CMake to locate.
log)
include_directories(libs/include)
set(DIR ../../../../libs)
add_library( avcodec-57
SHARED
IMPORTED )
set_target_properties( avcodec-57
PROPERTIES IMPORTED_LOCATION
${DIR}/armeabi-v7a/libavcodec-57.so )
add_library( avdevice-57
SHARED
IMPORTED)
set_target_properties( avdevice-57
PROPERTIES IMPORTED_LOCATION
${DIR}/armeabi-v7a/libavdevice-57.so )
add_library( avfilter-6
SHARED
IMPORTED)
set_target_properties( avfilter-6
PROPERTIES IMPORTED_LOCATION
${DIR}/armeabi-v7a/libavfilter-6.so )
add_library( avformat-57
SHARED
IMPORTED)
set_target_properties( avformat-57
PROPERTIES IMPORTED_LOCATION
${DIR}/armeabi-v7a/libavformat-57.so )
add_library( avutil-55
SHARED
IMPORTED )
set_target_properties( avutil-55
PROPERTIES IMPORTED_LOCATION
${DIR}/armeabi-v7a/libavutil-55.so )
add_library( postproc-54
SHARED
IMPORTED )
set_target_properties( postproc-54
PROPERTIES IMPORTED_LOCATION
${DIR}/armeabi-v7a/libpostproc-54.so )
add_library( swresample-2
SHARED
IMPORTED )
set_target_properties( swresample-2
PROPERTIES IMPORTED_LOCATION
${DIR}/armeabi-v7a/libswresample-2.so )
add_library( swscale-4
SHARED
IMPORTED)
set_target_properties( swscale-4
PROPERTIES IMPORTED_LOCATION
${DIR}/armeabi-v7a/libswscale-4.so )
# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.
target_link_libraries( # Specifies the target library.
native-lib
avutil-55
avcodec-57
avformat-57
avdevice-57
swresample-2
swscale-4
postproc-54
avfilter-6
# Links the target library to the log library
# included in the NDK.
${log-lib})
2、写代码
2.1、布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
</LinearLayout>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="12dp"
android:text=""
android:id="@+id/editText1" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="12dp"
android:text=""
android:id="@+id/editText2" />
<Button
android:text="开始解码为YUV"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/button" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
</ScrollView>
</LinearLayout>
2.2、生成jni头文件
新建FFmpeg.java文件,加载so库,定义native方法;
public class FFmpeg {
static {
System.loadLibrary("avutil-55");
System.loadLibrary("avcodec-57");
System.loadLibrary("avformat-57");
System.loadLibrary("avdevice-57");
System.loadLibrary("swresample-2");
System.loadLibrary("swscale-4");
System.loadLibrary("postproc-54");
System.loadLibrary("avfilter-6");
}
public static native int decode(String inputurl, String outputurl);
}
生成头文件;
命令行:javah 包名.类名
javah com.example.zjf.ffmpegdecoder.FFmpeg
将生成的头文件拖到cpp目录下,然后在native-lib.cpp中实现头文件的方法;
2.3、实现jni方法
添加用到的头文件;
#include <jni.h>
#include <string>
#ifdef __cplusplus
extern "C" {
#include <libavutil/log.h>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
#include "com_example_zjf_ffmpegdecoder_FFmpeg.h"
#include <android/log.h>
#define LOGE(format, ...) __android_log_print(ANDROID_LOG_ERROR, "(>_<)", format, ##__VA_ARGS__)
#define LOGI(format, ...) __android_log_print(ANDROID_LOG_INFO, "(^_^)", format, ##__VA_ARGS__)
#endif
/*
* Class: com_example_zjf_ffmpegdecoder_FFmpeg
* Method: decode
* Signature: (Ljava/lang/String;Ljava/lang/String;)I
*/
JNIEXPORT jint JNICALL Java_com_example_zjf_ffmpegdecoder_FFmpeg_decode
(JNIEnv *evn, jclass clazz, jstring inputurl, jstring outputurl){
}
#ifdef __cplusplus
}
#endif
这样就有了自动补全的功能;
jni代码;
#include <jni.h>
#include <string>
#ifdef __cplusplus
extern "C" {
#include <libavutil/log.h>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
#include "com_example_zjf_ffmpegdecoder_FFmpeg.h"
#include <android/log.h>
#define LOGE(format, ...) __android_log_print(ANDROID_LOG_ERROR, "(>_<)", format, ##__VA_ARGS__)
#define LOGI(format, ...) __android_log_print(ANDROID_LOG_INFO, "(^_^)", format, ##__VA_ARGS__)
#endif
/*
* Class: com_example_zjf_ffmpegdecoder_FFmpeg
* Method: decode
* Signature: (Ljava/lang/String;Ljava/lang/String;)I
*/
JNIEXPORT jint JNICALL Java_com_example_zjf_ffmpegdecoder_FFmpeg_decode
(JNIEnv *env, jclass clazz, jstring input_jstr, jstring output_jstr){
AVFormatContext *pFormatCtx;
int i,videoindex;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFrame *pFrame,*pFrameYUV;
uint8_t *out_buffer;
AVPacket *pPacket;
int y_size;
int ret, got_picture;
struct SwsContext *img_convert_ctx;
FILE *fp_yuv;
int frame_cnt;
clock_t time_start, time_finish;
double time_duration = 0.0;
char input_str[500]={0};
char output_str[500]={0};
char info[1000]={0};
sprintf(input_str,"%s",env->GetStringUTFChars(input_jstr, NULL));
sprintf(output_str,"%s",env->GetStringUTFChars(output_jstr, NULL));
/*初始化avformat并注册编译进avformat库里面所有的复用器(muxers),
解复用器(demuxers)和协议模块*/
av_register_all();
/**网络功能的全局初始化(可选的,在使用网络协议时有必要调用)*/
avformat_network_init();
//初始化一个AVFormatContext
pFormatCtx = avformat_alloc_context();
//打开输入的视频文件
if (avformat_open_input(&pFormatCtx,input_str,NULL,NULL) != 0){
LOGE("Couldn't open input stream.\n");
return -1;
}
//获取视频文件信息
if (avformat_find_stream_info(pFormatCtx,NULL) < 0){
LOGE("Couldn't find stream information.\n");
return -1;
}
videoindex = -1;
///遍历视音频流的个数
for (int i = 0; i < pFormatCtx -> nb_streams; i++) {
if (pFormatCtx->streams[i]/*视音频流*/->codec->codec_type == AVMEDIA_TYPE_VIDEO){
videoindex = i;
break;
}
}
if(videoindex==-1){
LOGE("Couldn't find a video stream.\n");
return -1;
}
//指向AVCodecContext的指针
pCodecCtx = pFormatCtx->streams[videoindex]->codec;
//指向AVCodec的指针.查找解码器
pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
if (pCodec == NULL)
{
LOGE("Couldn't find Codec.\n");
return -1;
}
//打开解码器
if (avcodec_open2(pCodecCtx,pCodec,NULL) < 0){
LOGE("Couldn't open codec.\n");
return -1;
}
//用来保存数据缓存的对像
pFrame = av_frame_alloc();
pFrameYUV = av_frame_alloc();
out_buffer=(unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height,1));
av_image_fill_arrays(pFrameYUV->data, pFrameYUV->linesize,out_buffer,
AV_PIX_FMT_YUV420P,pCodecCtx->width, pCodecCtx->height,1);
pPacket = (AVPacket *)av_malloc(sizeof(AVPacket));
img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
sprintf(info, "[Input ]%s\n", input_str);
sprintf(info, "%s[Output ]%s\n",info,output_str);
sprintf(info, "%s[Format ]%s\n",info, pFormatCtx->iformat->name);
sprintf(info, "%s[Codec ]%s\n",info, pCodecCtx->codec->name);
sprintf(info, "%s[Resolution]%dx%d\n",info, pCodecCtx->width,pCodecCtx->height);
fp_yuv=fopen(output_str,"wb+");
if(fp_yuv==NULL){
printf("Cannot open output file.\n");
return -1;
}
frame_cnt = 0;
time_start = clock();
while(av_read_frame(pFormatCtx, pPacket) >= 0){
if(pPacket->stream_index == videoindex){
ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, pPacket);
if(ret < 0){
LOGE("Decode Error.\n");
return -1;
}
if(got_picture){
sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
pFrameYUV->data, pFrameYUV->linesize);
y_size=pCodecCtx->width*pCodecCtx->height;
fwrite(pFrameYUV->data[0],1,y_size,fp_yuv); //Y
fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv); //U
fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv); //V
//Output info
char pictype_str[10]={0};
switch(pFrame->pict_type){
case AV_PICTURE_TYPE_I:sprintf(pictype_str,"I");break;
case AV_PICTURE_TYPE_P:sprintf(pictype_str,"P");break;
case AV_PICTURE_TYPE_B:sprintf(pictype_str,"B");break;
default:sprintf(pictype_str,"Other");break;
}
LOGI("Frame Index: %5d. Type:%s",frame_cnt,pictype_str);
frame_cnt++;
}
}
av_free_packet(pPacket);
}
while (1) {
ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, pPacket);
if (ret < 0)
break;
if (!got_picture)
break;
sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
pFrameYUV->data, pFrameYUV->linesize);
int y_size=pCodecCtx->width*pCodecCtx->height;
fwrite(pFrameYUV->data[0],1,y_size,fp_yuv); //Y
fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv); //U
fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv); //V
//Output info
char pictype_str[10]={0};
switch(pFrame->pict_type){
case AV_PICTURE_TYPE_I:sprintf(pictype_str,"I");break;
case AV_PICTURE_TYPE_P:sprintf(pictype_str,"P");break;
case AV_PICTURE_TYPE_B:sprintf(pictype_str,"B");break;
default:sprintf(pictype_str,"Other");break;
}
LOGI("Frame Index: %5d. Type:%s",frame_cnt,pictype_str);
frame_cnt++;
}
time_finish = clock();
time_duration=(double)(time_finish - time_start);
sprintf(info, "%s[Time ]%fms\n",info,time_duration);
sprintf(info, "%s[Count ]%d\n",info,frame_cnt);
sws_freeContext(img_convert_ctx);
fclose(fp_yuv);
av_frame_free(&pFrameYUV);
av_frame_free(&pFrame);
avcodec_close(pCodecCtx);
avformat_close_input(&pFormatCtx);
return 0;
}
#ifdef __cplusplus
}
#endif
MainActivity.java
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private Button button;
private EditText editText1,editText2;
private DecodeAsyncTask myTask;
String folderurl;
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("native-lib");
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.button);
editText1 = (EditText) findViewById(R.id.editText1);
editText2 = (EditText) findViewById(R.id.editText2);
folderurl = Environment.getExternalStorageDirectory().getPath();
myTask = new DecodeAsyncTask();
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final String inputurl=folderurl+"/"+editText1.getText().toString();
final String outputurl=folderurl+"/"+editText2.getText().toString();
Log.d(TAG,"" + inputurl + " " + outputurl);
myTask.execute(inputurl,outputurl);
}
});
}
@Override
protected void onPause() {
super.onPause();
//如果异步任务不为空 并且状态是 运行时 ,就把他取消这个加载任务
if(myTask !=null && myTask.getStatus() == AsyncTask.Status.RUNNING){
myTask.cancel(true);
}
}
private class DecodeAsyncTask extends AsyncTask<String,Void,Void>{
@Override
protected Void doInBackground(String... strings) {
FFmpeg.decode(strings[0],strings[1]);
return null;
}
}
}
运行截图
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