目录
- 程序的流程简介
- 编译FFmepg类库
- 编写FFmpeg调用代码
- 编写Android.mk
- 运行输出
参考
- [1] 雷霄骅/最简单的基于FFmpeg的移动端例子：Android HelloWorld
1. 程序的流程简介
Android应用使用FFmpeg类库的流程图如下所示:
FFmpegInAndroid.png
上图的流程可以分为
- “编译FFmpeg类库”
- “编写Java代码”
- “编写native代码”
- “编写Android.mk”。
2. 编译FFmepg类库
参照：FFmpeg编译-Android平台
3. 编写FFmepg调用代码
编写获取FFmpeg支持信息的方法：
//FFmpeger.h
#ifndef HELLOJNI_FFMPEGER_H
#define HELLOJNI_FFMPEGER_H
class FFmpeger {
public:
/**
* FFmpeg类库支持的封装格式
*/
static void avformat_info(char *);
/**
* FFmpeg类库支持的编解码器
*/
static void avcodec_info(char *);
/**
* FFmpeg类库支持的滤镜
*/
static void avfilter_info(char *);
/**
* FFmpeg类库的配置信息
*/
static void avcodec_config(char *);
};
#endif //HELLOJNI_FFMPEGER_H
//FFmpeger.cpp
#include "FFmpeger.h"
extern "C"
{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libavfilter/avfilter.h"
}
void FFmpeger::avformat_info(char *info) {
av_register_all();
AVInputFormat *avInputFormat = av_iformat_next(NULL);
AVOutputFormat *avOutputFormat = av_oformat_next(NULL);
while(avInputFormat != NULL) {
sprintf(info, "%s[In ][%10s]\n", info, avInputFormat->name);
avInputFormat = avInputFormat->next;
}
while(avOutputFormat != NULL) {
sprintf(info, "%s[Out][%10s]\n", info, avOutputFormat->name);
avOutputFormat = avOutputFormat->next;
}
}
void FFmpeger::avcodec_info(char *info) {
av_register_all();
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;
}
}
void FFmpeger::avfilter_info(char *info) {
avfilter_register_all();
AVFilter *avFilter = (AVFilter *) avfilter_next(NULL);
while (avFilter != NULL) {
sprintf(info, "%s[%10s]\n", info, avFilter->name);
avFilter = avFilter->next;
}
}
void FFmpeger::avcodec_config(char *info) {
av_register_all();
sprintf(info, "%s[%10s]\n", avcodec_configuration());
}
使用的方法和数据结构说明
- AVInputFormat,AVOutputFormat：描述支持的输入/输出格式的结构体。
- AVCodec：存储编解码器信息的结构体。
- AVFilter：滤镜信息结构体。
- av_register_all()：初始化所有组件，只有调用了该函数，才能使用复用器和编解码器。
- av_iformat_next，av_oformat_next()：用来递归获取所有已注册的输入/输出格式。
- av_codec_next：获取指向链表下一个解码器的指针，如果想要获得指向第一个解码器的指针，则将该函数的参数设置为NULL。
- avfilter_register_all：注册所有内置AVFilter。
- avcodec_configuration：获取FFmpeg类库的配置信息。
//MainActivity.java
package com.smallest.test.hellojni;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import android.text.method.ScrollingMovementMethod;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Example of a call to a native method
TextView tv = (TextView) findViewById(R.id.sample_text);
tv.setText(stringFromJNI());
tv.setMovementMethod(ScrollingMovementMethod.getInstance());
}
/**
* A native method that is implemented by the 'native-lib' native library,
* which is packaged with this application.
*/
public native String stringFromJNI();
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("avutil");
System.loadLibrary("swresample");
System.loadLibrary("avcodec");
System.loadLibrary("avformat");
System.loadLibrary("swscale");
System.loadLibrary("avfilter");
System.loadLibrary("avdevice");
System.loadLibrary("hello-jni");
}
}
JNI层的调用代码：
//
#include
#include
#include
#include "com_smallest_test_hellojni_MainActivity.h"
#include "FFmpeger.h"
#include
JNIEXPORT jstring JNICALL Java_com_smallest_test_hellojni_MainActivity_stringFromJNI(JNIEnv *env, jobject thiz)
{
char info[60000] = {0};
FFmpeger::avformat_info(info);
__android_log_print(ANDROID_LOG_INFO,"myTag","avformatInfo:\n%s", info);
char info2[60000] = {0};
FFmpeger::avcodec_info(info2);
__android_log_print(ANDROID_LOG_INFO,"myTag","avcodecInfo:\n%s", info2);
char info3[60000] = {0};
FFmpeger::avfilter_info(info3);
__android_log_print(ANDROID_LOG_INFO,"myTag","avfilterInfo:\n%s", info3);
char info4[60000] = {0};
FFmpeger::avcodec_config(info4);
__android_log_print(ANDROID_LOG_INFO,"myTag","avcodecConfiguration:\n%s", info4);
char infoTotal[300000] = {0};
sprintf(infoTotal, "avformatInfo:\n%s avcodecInfo:\n%s avfilterInfo:\n%s avcodecConfiguration:\n%s", info, info2, info3, info4);
return (*env).NewStringUTF(infoTotal);
}
4. 编写Android.mk文件
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
#FFmpeg 库的路径
FFMPEG_LIB_PATH:=$(LOCAL_PATH)/../libs
include $(CLEAR_VARS)
LOCAL_MODULE:= libavcodec
LOCAL_SRC_FILES:= $(FFMPEG_LIB_PATH)/libavcodec.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE:= libavformat
LOCAL_SRC_FILES:= $(FFMPEG_LIB_PATH)/libavformat.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE:= libswscale
LOCAL_SRC_FILES:= $(FFMPEG_LIB_PATH)/libswscale.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE:= libavutil
LOCAL_SRC_FILES:= $(FFMPEG_LIB_PATH)/libavutil.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE:= libavfilter
LOCAL_SRC_FILES:= $(FFMPEG_LIB_PATH)/libavfilter.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE:= libswresample
LOCAL_SRC_FILES:= $(FFMPEG_LIB_PATH)/libswresample.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE:= libavdevice
LOCAL_SRC_FILES:= $(FFMPEG_LIB_PATH)/libavdevice.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := hello-jni
LOCAL_C_INCLUDES := $(LOCAL_PATH)/../include
LOCAL_SRC_FILES := $(wildcard $(LOCAL_PATH)/../src/*.cpp)
LOCAL_LDLIBS := -llog
LOCAL_SHARED_LIBRARIES := libavcodec libavfilter libavformat libavutil libswresample libswscale libavdevice
include $(BUILD_SHARED_LIBRARY)
Application.mk如下：
APP_BUILD_SCRIPT := Android.mk
APP_ABI := armeabi
5. 运行输出
ffmpeg_hh.jpg